A new study by Eugénie Joltreau and Luis Sarmiento, researchers at the CMCC Foundation – Euro-Mediterranean Center on Climate Change, published in the Journal of Applied Economics, sets out to change that. The research combines a theoretical model of international waste markets with trade data covering plastics, paper, aluminium, glass, and iron and steel. Its central finding is striking: global trade in recyclable waste has held steady at roughly 170 to 200 million tonnes per year since 2010, and between 2018 and 2021 an average of 10 to 13 percent of European Union packaging recycling actually took place outside the bloc.

The scale and concentration of this market are remarkable. In 2022, high-income countries exported up to 72 million tonnes more recyclable waste than they imported, effectively shipping their surplus discards to the rest of the world. The market is also highly concentrated: the ten largest exporting countries account for 67 percent of global exports. Recycling, in other words, is not a purely local activity but a global commodity trade with its own economics, price signals and policy distortions.

At the heart of the study lies a concept the authors call material imbalance: the mismatch between the materials a country needs for production and the waste it generates through consumption. A service-based economy may import many manufactured products and generate large volumes of waste while requiring relatively few raw materials for its own industry. A rapidly industrialising economy presents the opposite profile, with strong demand for materials but less locally available waste. These complementary differences make international trade economically attractive, with waste flowing from countries that generate relatively more of a material to those that need it more. Transport costs, along with the costs of collecting, recycling and disposing of waste, determine whether such trade actually takes place.

The researchers tested this relationship empirically using international trade data, and the results support the idea that material imbalances are a significant driver of global waste flows. The fact that waste was being directed towards countries with high material needs, such as China at the time, led us to think more deeply about the relationship between the waste countries generate and the materials they need for production, Joltreau explains. This led us to introduce the concept of material imbalance into the theoretical model and then test it empirically. We found that these imbalances do indeed play a role in explaining international trade in recyclable waste.

The theoretical model also reveals why recyclable waste does not behave like an ordinary product. Depending on demand, transport and processing costs, its price can be positive or negative. An importer may pay for waste as a useful source of materials, or an exporter may pay another country to take it away. This dual nature explains the conflicting narratives that emerged when China, then the world’s leading importer of waste, drastically reduced its imports. Some observers claimed that wealthy nations were simply exporting their trash, while others insisted that importing countries were buying valuable recyclable materials. The research shows that both narratives can contain part of the truth: recyclable waste is simultaneously an unwanted by-product that is costly to manage and a potential input for production, and its value can shift as market conditions and public policies change.

One of the insights from the model is that the price of waste traded for recycling can shift from positive to negative, depending on demand and costs, which are themselves influenced by recycling policies, Joltreau notes. This insight has direct policy consequences. Recycling and waste-management policies influence not only how much material is recycled but also where that recycling takes place. Collection and recycling subsidies, disposal taxes and recycling targets can increase or reduce the incentive to export, depending on how they are designed. Some policies can lower the cost of preparing waste for export, making it attractive to ship recyclable materials abroad rather than process them domestically.

The European Union illustrates this connection vividly. Waste exported for recycling can count towards national packaging recycling targets, which means that a higher reported recycling rate does not necessarily reflect more domestic recycling. According to the model, for countries that tend to export waste, targets requiring recycled materials to be used in domestic production may do more to support local recycling than targets focused only on the share of waste recycled. In effect, a country can appear to be recycling successfully while the actual processing, and its environmental burden, happens elsewhere.

The findings do not imply that international waste trade is inherently harmful. Trade can connect available recyclable materials with industries that genuinely need them, improving efficiency across the global economy. However, the study warns that poorly designed policies may encourage exports without strengthening domestic recycling systems, while shifting environmental pressures towards importing countries that may have lower environmental standards or weaker collection infrastructure. The environmental benefits of recycling, in such cases, may be partially offset by the impacts of transport and by substandard processing abroad.

By placing international trade at the centre of circular-economy analysis, the research highlights the need for policymakers to look beyond national recycling rates. Effective policies must consider where waste is processed, where recycled materials are used and how incentives affect global flows, while continuing to reduce overall resource use and waste generation. As the world’s waste markets continue to evolve, understanding the hidden economics of recyclable waste will be essential for building a circular economy that delivers real environmental benefits rather than simply relocating them.

Subject of Research: International trade in recyclable waste and the policy design of recycling systems

Article Title: The hidden global market behind recycling

Article References: The hidden global market behind recycling. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: recycling, waste trade, circular economy, material imbalance, EU packaging recycling, waste exports, recycling policy, CMCC, Journal of Applied Economics, plastics, global waste market, environmental policy

Materials scientist Athina Anastasaki has spent years pursuing the dream of efficiently unmaking acrylic glass. Her group previously demonstrated that depolymerisation of the polymer was possible in principle, but only under restrictive conditions. In earlier work, the polymer chains had to be chemically modified to introduce deliberate weak points that would snap under heat. Other strategies demanded large volumes of solvents, substantial quantities of catalysts, or ultraviolet light to initiate or sustain the reaction. Each of these requirements added cost, complexity and environmental burden, keeping the process firmly in the laboratory rather than the factory.

The new approach, published in the journal Nature Chemistry, strips away nearly all of that complexity. Using a single commercially available and inexpensive reagent belonging to a class of compounds known as N-hydroxyimides, the researchers can break acrylic glass polymer chains apart and release the constituent monomers with yields as high as 98 percent. Once the reagent is added, the reaction proceeds on its own, with no need for external energy inputs beyond modest heating. The recovered monomers are extremely pure, even when the starting material contains dyes or other contaminants, and they can be repolymerised into new acrylic glass of the same quality as virgin material produced from fossil feedstocks.

The energy savings are equally striking. Depolymerisation with the new method begins at just over 200 degrees Celsius, whereas conventional approaches require a minimum of 400 degrees. The process also uses no solvents whatsoever, eliminating an entire category of cost, handling and waste management. Richard Whitfield, lead author of the study and a former research associate in Anastasaki’s group, emphasised that the simplicity of the approach is what makes it so exciting. In a field where chemical recycling schemes often collapse under the weight of their own operational demands, a one-reagent, solvent-free, low-temperature process stands out as a genuine departure.

The choice of reagent was the product of systematic searching rather than luck. Anastasaki’s group collaborated with ETH chemistry professors Tae-Lim Choi and Gunnar Jeschke to screen and understand candidate compounds, work that Anastasaki credits as essential to resolving many of the questions that would otherwise have remained unanswered. Even so, the team was startled by how clean the final answer turned out to be. Anastasaki noted that the only thing that surprised the researchers was that a single chemical really was sufficient to drive the reaction, a result that defies the intuition that complex polymer breakdown requires equally complex chemistry.

To appreciate why this matters, it helps to compare the new method with the dominant form of chemical plastics recycling, pyrolysis. In pyrolysis, plastic polymers are broken down at high temperatures, usually above 400 degrees Celsius, an energy-intensive process that accounts for a large share of its operating cost. Moreover, the monomers recovered from pyrolysis are often relatively impure, with impurity levels reaching as high as 3 percent. Those contaminants propagate into the next generation of plastic, degrading its quality and limiting the applications for which recycled material can be used. The ETH process, by contrast, delivers monomers of exceptional purity from a reaction that starts more than 200 degrees cooler, in bulk, without solvents.

The commercial implications have not gone unnoticed. ETH Zurich has filed a patent application for the method and is now seeking licensees, and the chemical industry has already expressed interest. A key selling point is compatibility: the process can be implemented using existing infrastructure and standard industrial processes. Anastasaki explained that the drawback of her group’s previous approaches was that companies would have had to modify their processes and equipment to implement them, an expense that most companies would find prohibitive. By fitting into the reactors and workflows that manufacturers already operate, the new method removes the single largest barrier that has kept laboratory advances in polymer recycling from reaching production lines.

Anastasaki is under no illusions about the competitive landscape. Competition in chemical plastics recycling is fierce, she noted, particularly in the United States, where large and well-funded research groups are working in the same field. What allows her to hold her own, she said, is the solid core funding provided by ETH Zurich, and this time her team is even one step ahead of its American competitors. That head start, combined with a pending patent and active industry interest, positions the N-hydroxyimide approach as one of the most immediately translatable advances in polymer chemistry to emerge from an academic laboratory in recent years.

There is, however, one small catch. The method works only with acrylic glass; different approaches are needed to break down other plastics into their constituent building blocks. Acrylic glass, chemically a polymethacrylate, possesses chain structures that respond to the N-hydroxyimide reagent in a way that other common polymers do not. This specificity is both a strength and a limitation. It guarantees the purity and efficiency that make the process economically viable, but it means the method cannot simply be extended to the broader plastic waste stream without further innovation.

Anastasaki’s next steps are to scale up the method and to gain a detailed understanding of the reaction mechanisms at work. Building on that knowledge, the ETH researchers aim to develop substances that will further accelerate polymer breakdown and improve the monomer yield even beyond the already impressive 98 percent. The materials scientist remains optimistic about extending the principle beyond acrylic glass, stating that the team will try to apply the same approach to polystyrene, one of the most widely used plastics in the world. If that effort succeeds, the single-reagent strategy that just made acrylic glass recycling economically viable could become a template for dismantling the plastic waste problem one polymer at a time.

Subject of Research: Chemical recycling of acrylic glass using a single N-hydroxyimide reagent

Article Title: New method makes acrylic glass recycling economically viable

Article References: New method makes acrylic glass recycling economically viable. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: acrylic glass, recycling, depolymerisation, polymers, ETH Zurich, Nature Chemistry, N-hydroxyimides, chemical recycling, monomers, plastic waste, sustainability, materials science

The research team, led by A. K. M. Mohsin of the University of Applied Sciences Upper Austria and the Supply Chain Intelligence Institute Austria, compiled a balanced country-year panel covering 2010 to 2023, yielding 126 observations from Eurostat, the European Alternative Fuels Observatory, the International Energy Agency, the World Bank Logistics Performance Index, BloombergNEF, and publicly disclosed corporate sustainability reports. The dependent variable, cost efficiency, was measured as the average production cost of lithium-ion batteries in euros per kilowatt-hour after accounting for the economic benefits of circular resource recovery. Across the sample, this figure averaged 86.65 euros per kilowatt-hour with a standard deviation of just 4.66, indicating that production costs were remarkably similar across countries even though the underlying technological, operational, and policy conditions varied enormously.

That heterogeneity is striking. Production capacity ranged from 29 to 148 gigawatt-hours, research and development investment spanned from 22.08 to 498.86 million euros, and logistics costs varied from 100.56 to 982.99 euros per unit. Recycling efficiency, by contrast, was already well developed, averaging 82.09 percent with values between 70 and 93 percent. The pattern suggests that broadly comparable cost outcomes can be reached through very different combinations of industrial scale, innovation spending, logistics coordination, and policy support, a possibility the authors set out to test formally rather than assume.

To do so, the team deployed an unusually rich methodological arsenal. Panel autoregressive distributed lag models estimated short-run and long-run relationships between cost efficiency and its operational, technological, and policy determinants. Nonlinear ARDL models then examined whether positive and negative changes in logistics costs and government subsidies produce asymmetric responses. Necessary Condition Analysis identified minimum constraint levels associated with higher cost efficiency, and fuzzy-set Qualitative Comparative Analysis explored alternative configurations through which conditions jointly contribute to efficient circular supply chain outcomes. The combination is novel in the battery circularity literature, where most prior work has relied on static regression techniques or small-scale case studies.

The econometric results are technically revealing. In the long run, a 1 percent increase in recycling efficiency leads to a 0.019 percent rise in cost efficiency, while a 1 percent increase in production capacity produces a 0.128 percent gain, reflecting economies of scale in manufacturing. Counterintuitively, logistics costs also show a positive long-run effect, with a 1 percent increase associated with a 0.016 percent improvement in cost efficiency. The authors interpret this as evidence that higher logistics expenditure often reflects strategic investment in reverse logistics infrastructure, digital traceability systems, and battery collection networks rather than operational waste. In the short run, research and development investment shows a significant positive effect, with a 1 percent increase yielding a 0.024 percent cost efficiency gain, and the error correction term of negative 0.726 indicates that roughly 72.6 percent of any disequilibrium is corrected each period, a relatively fast adaptation.

The nonlinear analysis confirms that these relationships are asymmetric. A positive shock in logistics costs produces a 0.028 percent long-run gain in cost efficiency, while a positive shock in government subsidies delivers a much larger 0.218 percent improvement, underscoring the outsized role of public financial support. Wald tests reveal long-run asymmetry for logistics costs, meaning efficiency gains from logistics investment persist and are not reversible, and short-run asymmetry for subsidies, meaning cost efficiencies achieved through government incentives remain intact even if subsidies later decline. Granger causality tests, using heteroskedasticity-robust estimation, provide comparatively stronger evidence that changes in government support precede changes in cost efficiency, though the authors caution this reflects predictive temporal precedence rather than proof of direct causation.

The Necessary Condition Analysis adds a crucial structural insight: government subsidies are the only condition whose necessity effect exceeds the minimum threshold, establishing that adequate financial backing is an indispensable enabler of cost efficiency. Bottleneck analysis shows that achieving cost efficiency outcomes above 60 percent requires minimum threshold levels of 1.626 percent for government subsidies, 4.065 percent for logistics cost, 0.813 percent for production capacity, and 0.813 percent for research and development investment. To gain an additional 10 percent in cost efficiency, subsidies must rise from 1.626 to 7.317 percent, and for outcomes above 80 percent, the model recommends combinations of 28.45 to 34.959 percent subsidies, 8.13 to 12.195 percent logistics cost, and 0.813 percent each for capacity and research investment. Recycling efficiency, logistics cost, production capacity, and research investment all contribute, but none functions as an absolute constraint on its own.

The fuzzy-set Qualitative Comparative Analysis then reveals that there is no universal pathway to cost-efficient circularity. Multiple configurations, each with high consistency scores, lead to favorable outcomes. One solution combines high recycling efficiency with optimized logistics cost, with subsidies as a peripheral factor. Another pairs production capacity, research investment, and logistics optimization. A third places government subsidies at the core, amplified when combined with recycling efficiency or research investment. The analysis also identifies configurations associated with low cost efficiency, such as overinvestment in production capacity and research without sufficient recycling integration, or subsidies paired with excessive logistics costs and no optimization. The authors note that battery chemistry matters, since chemistries rich in nickel, cobalt, and manganese provide stronger economic incentives for material recovery than those with lower recovery values.

Interpreted through Resource-Based Theory, Institutional Theory, and Dynamic Capabilities Theory, the findings suggest that supportive institutional environments encourage firms to invest in technological innovation and circular practices, while dynamic capabilities enable organizations to transform those investments into sustained economic performance. The authors also developed a causal loop diagram showing how reinforcing loops of innovation and efficiency, scale and learning, and policy support interact with balancing constraints such as logistics cost drag, framing circular cost efficiency as a continuously evolving equilibrium maintained by technological innovation, institutional stability, and adaptive market behavior.

For policymakers, the study offers a prioritized roadmap. The highest priority is to establish stable and predictable financial incentive frameworks, since subsidies emerged as the fundamental enabler. The second is to strengthen intelligent reverse logistics infrastructure and digital traceability systems to improve battery collection and material recovery. Finally, policy measures should operate synergistically, simultaneously supporting recycling technology innovation, research investment, and logistics network development. The authors caution that the findings are based on the European Union, where comprehensive battery regulations and strong policy support provide a mature institutional environment, and should be generalized to other regions with appropriate care. Future research, they suggest, could extend the analysis to firm-level data, comparative studies across China and the United States, and emerging technologies such as solid-state and sodium-ion batteries, which may substantially alter recycling requirements and circular supply chain configurations.

Subject of Research: Cost efficiency in circular lithium-ion battery supply chains under circular economy and policy synergies in Europe

Article Title: Integrating circular economy and policy synergies for cost-efficient lithium-ion battery supply chains

Article References: Mohsin, A. K. M., Rashed, M., Gerschberger, M., Ahmed, S. F., Bartuska, L., Schwarz, C., & Kamal Uddin, M. (2026). Integrating circular economy and policy synergies for cost-efficient lithium-ion battery supply chains. Clean Technologies and Environmental Policy, 28(11), Article 282. https://doi.org/10.1007/s10098-026-03613-6

Image Credits: AI Generated

DOI: 10.1007/s10098-026-03613-6

Keywords: lithium-ion batteries, circular economy, supply chains, recycling, government subsidies, reverse logistics, cost efficiency, electric vehicles, panel ARDL, Necessary Condition Analysis, fsQCA, EU Battery Regulation

The review, led by Shruthi Yerraju and Sumana Chenna of CSIR-IICT in Hyderabad together with Karunakaran Venugopal and C. Anandharamakrishnan of CSIR-NIIST in Thiruvananthapuram, was conducted as a structured literature analysis using defined search terms, explicit inclusion and exclusion criteria, and PRISMA-based screening, the standard protocol for systematic reviews. Rather than treating packaging design, recycling technologies, biodegradable materials, environmental assessment, and policy as separate silos, the authors deliberately integrated them into a single analytical framework, a move they argue distinguishes their work from earlier reviews that examined these dimensions independently.

At the heart of the analysis is a sobering comparison of recycling pathways. The researchers critically evaluated mechanical recycling, chemical recycling, and energy recovery against four yardsticks: environmental performance, technology readiness, scalability, and suitability for different waste streams. Their conclusion is deliberately unsentimental. No single pathway wins outright, because effectiveness varies with polymer type, feedstock quality, energy demand, technology maturity, and the regional infrastructure available to process the waste. Mechanical recycling, which shreds, washes, and remelts plastics like polyethylene terephthalate and high-density polyethylene, remains the most mature option but falters on contaminated, multilayer, or mixed waste. Chemical recycling, including pyrolysis and depolymerization, can break polymers back down to monomers or feedstocks, offering a route for plastics that mechanical systems cannot handle, but it typically demands more energy and sits at lower technology readiness levels.

The polymer chemistry itself complicates matters. The review catalogs an extensive range of packaging plastics, from commodity polyolefins such as polyethylene and polypropylene to engineering polymers like polycarbonate and polyvinyl chloride, alongside a growing roster of biodegradable alternatives. Among the latter, polylactic acid, polyhydroxyalkanoates, polybutylene succinate, and polycaprolactone are the most prominent, each with distinct degradation kinetics, mechanical properties, and end-of-life requirements. Polylactic acid, derived from fermented plant starch, composts under industrial conditions but degrades slowly in ambient landfills. Polyhydroxyalkanoates, synthesized by bacteria, offer genuine marine biodegradability but remain expensive to produce at scale. The authors stress that biodegradability is not a universal escape hatch: without the composting or anaerobic digestion infrastructure to process these materials, they can end up contaminating conventional recycling streams, where even small amounts of PLA can compromise the quality of recycled PET.

Emerging feedstocks are also reshaping the materials landscape. The review highlights agricultural and agro-industrial waste as a promising source of biopolymers, including cellulose nanofibers extracted from wheat straw and orange peel, chitosan from crustacean shells, and pectin from fruit processing residues. These materials can form edible films and coatings, active packaging with antimicrobial properties, and barrier layers that reduce reliance on fossil-derived polymers. Nanocellulose films, in particular, have shown enhanced barrier and antioxidant performance in coating applications, while lignin, an abundant byproduct of papermaking, is being repurposed as a functional material for active packaging. The circular logic is appealing: waste from one industry becomes feedstock for another, reducing both disposal burdens and virgin material demand.

On the assessment side, the review examines two complementary analytical tools. Life cycle assessment quantifies environmental impacts across a product’s entire existence, from raw material extraction through manufacturing, use, and disposal, typically reporting metrics such as global warming potential. Material flow analysis, by contrast, tracks the physical stocks and flows of materials through an economy, revealing where plastics accumulate, leak, or cycle. The authors argue that neither tool alone is sufficient: LCA can identify that a reusable packaging system outperforms a single-use equivalent, but only after a certain number of reuse cycles, a threshold that depends on transport distances and washing energy. MFA can expose the sheer scale of material leakage, such as the finding that more than 1,000 rivers account for 80 percent of global riverine plastic emissions into the ocean. Used together, they provide both the environmental scorecard and the material balance sheet needed to steer policy.

Policy instruments receive equally close scrutiny. The review evaluates extended producer responsibility, deposit-return systems, and recycled-content mandates as the three principal levers for promoting resource circulation. Extended producer responsibility shifts the financial and operational burden of managing packaging waste from municipalities to the producers who put packaging on the market, creating an economic incentive to design for recyclability. Deposit-return systems, which charge consumers a small refundable fee at purchase, have demonstrated high collection rates for beverage containers in multiple jurisdictions. Recycled-content mandates, such as those embedded in the European Union’s Packaging and Packaging Waste Regulation, force demand for secondary materials, giving recyclers a guaranteed market. The authors note that these instruments work best in combination, and that their effectiveness depends heavily on regional governance capacity and enforcement.

The digital dimension may prove the most transformative frontier. The review surveys artificial intelligence-assisted sorting, which uses machine learning and near-infrared spectroscopy to identify polymer types on conveyor belts with increasing speed and accuracy, blockchain-enabled traceability that can verify the provenance of recycled content across supply chains, digital product passports that encode a package’s material composition and recycling instructions in a machine-readable format, and smart monitoring systems based on the Internet of Things and radio frequency identification. These technologies promise to enhance segregation, recycling efficiency, and supply-chain transparency, but the authors are candid about the barriers: cost, data availability, interoperability between systems, and the underlying infrastructure required to deploy them at scale remain significant hurdles, particularly in developing economies where informal waste sectors handle a large share of collection.

What emerges from the synthesis is not a blueprint but a decision framework. The authors argue that circular business models, from refill-and-reuse systems to product-as-service arrangements, must be matched to the specific technological and infrastructural context of each region. A deposit-return scheme that works in a European city with mature collection infrastructure may fail in a rapidly urbanizing region where waste collection itself is unreliable. Similarly, the choice between mechanical and chemical recycling should be driven by the local waste stream composition, energy prices, and the availability of markets for recycled outputs. The review’s contribution lies in making these trade-offs explicit, offering researchers, industry, and decision-makers a holistic roadmap for prioritizing innovation, accelerating technology adoption, and enabling the large-scale deployment of sustainable circular packaging systems. As plastic waste generation continues to outpace recycling capacity, the window for incremental fixes is closing; the authors suggest that only an integrated strategy, one that treats materials, technology, policy, and digitalization as a single system, can bend the curve.

Subject of Research: Circular economy roadmap for packaging waste: recycling, bioplastics, and digital tools converge

Article Title: Sustainable packaging waste management: circular economy strategies, technological innovations, and future perspectives

Article References: Yerraju, S., Venugopal, K., Anandharamakrishnan, C., & Chenna, S. (2026). Sustainable packaging waste management: circular economy strategies, technological innovations, and future perspectives. Clean Technologies and Environmental Policy, 28(11), Article 281. https://doi.org/10.1007/s10098-026-03628-z

Image Credits: AI Generated

DOI: 10.1007/s10098-026-03628-z

Keywords: circular economy, plastic packaging, recycling, biodegradable plastics, extended producer responsibility, life cycle assessment, AI sorting, digital product passport, sustainable packaging, plastic waste, Sustainable, packaging

The scale of the challenge is enormous. Electronic waste is among the fastest-growing waste categories globally, and plastics loaded with brominated flame retardants represent a substantial fraction of it. These plastics, typically acrylonitrile butadiene styrene or high-impact polystyrene, are deliberately engineered to resist fire, which makes them nearly impossible to recycle safely. When heated through conventional pyrolysis, the brominated compounds release toxic organic species, including brominated dioxins and furans, while the antimony tends to volatilize or become trapped in ash, escaping recovery entirely. Existing recycling routes cause metal losses and toxic emissions, and antimony itself is classified as a critical metal with constrained supply, mined predominantly in a handful of countries.

The Rice team’s answer is a technique they call isothermal-clamped flash Joule heating, or IC-FJH. Flash Joule heating has already gained attention in recent years for its ability to convert waste materials into valuable products in seconds, from turning plastic into graphene to regenerating spent battery cathodes. The new variant clamps the reaction zone isothermally, creating a spatially uniform high-temperature environment within seconds rather than the slow, uneven heating that conventional furnaces produce. This uniformity is not merely a technical nicety; it fundamentally changes the chemistry that unfolds inside the plastic.

When the researchers applied IC-FJH to flame-retardant ABS plastic, three key chemical effects emerged. First, the ultrafast heating suppressed volatilization of brominated organic intermediates, preventing them from escaping into the gas stream as toxic pollutants. Second, the process promoted hydrogen-assisted hydrodebromination, a reaction in which hydrogen strips bromine atoms from the organic flame retardant molecules and converts them into hydrogen bromide, a capturable and industrially useful acid. Third, the intense reductive environment drove the formation of elemental antimony, Sb(0), from the antimony trioxide synergist, transforming a widely dispersed oxide into a concentrated metallic phase that can be physically separated.

The performance numbers are striking. IC-FJH recovered approximately 90 percent of the antimony from the plastic at over 97 percent purity, a level of selectivity that conventional thermal treatments cannot approach. At the same time, 83 percent of the bromine was captured as HBr rather than released as hazardous organic species. Compared with slow heating, the flash process reduced toxic brominated organic species by 34 to 51 percent, meaning that even the fraction of bromine not converted to HBr was far less likely to end up as dioxin-forming intermediates. The recovered antimony emerges as a metallic resource that can re-enter the supply chain for new flame retardants, semiconductors or other antimony-dependent technologies.

To understand why the flash process works so differently from conventional heating, the team combined experimental characterization with computational modeling. Density functional theory calculations, using climbing-image nudged elastic band methods to map reaction pathways, revealed how the reductive environment and rapid thermal cycling favor Sb(0) formation over antimony volatilization. Heat-transfer simulations confirmed that the isothermal clamping produces a uniform temperature field across the plastic sample, eliminating the cold zones where brominated intermediates would otherwise survive and later escape. Machine learning analyses helped the researchers correlate process parameters with product outcomes, providing a data-driven framework for optimizing the reaction.

The generality and scalability of the approach were tested across different plastic formulations and batch sizes, with the results documented in figures showing Sb recovery performance under different heating rates and debromination behavior under IC-FJH conditions. The team also examined how bromine partitions between gas, liquid and solid phases during the process, and how antimony transforms through successive oxidation states as the reaction proceeds. These mechanistic insights into ABS plastic pyrolysis suggest the method is not a narrow trick tuned to one specific waste stream but a robust platform applicable to the broader family of halogenated flame-retardant plastics found in real electronic waste.

Perhaps the most consequential findings come from the life-cycle assessment and techno-economic analysis that accompanied the experimental work. The LCA indicates reductions of 72 percent in resource consumption, 65 percent in climate-change burdens, 80 percent in water use and 100 percent in polycyclic aromatic hydrocarbon formation relative to conventional antimony recovery and plastic treatment pathways. The complete elimination of PAH formation is particularly significant, as these carcinogenic compounds are a persistent byproduct of slow pyrolysis of halogenated plastics. The techno-economic analysis, whose source code is publicly available on GitHub, suggests the process could be economically viable, supported in part by the fact that flash Joule heating consumes electricity rather than fossil fuel heat and operates on timescales of seconds rather than hours.

The research builds on a growing body of work from the Tour laboratory demonstrating that electrothermal processing can transform waste management across multiple domains. Previous studies from the group have shown flash Joule heating converting waste plastic into graphene at zero net cost, regenerating spent lithium cobalt oxide cathodes, separating rare earth elements in seconds, and removing iron and heavy metals from bauxite residues through flash chlorination. The common thread is that passing current directly through a waste material, rather than heating it externally, enables reaction chemistries that are inaccessible to conventional thermal processing. The new antimony and debromination work extends this paradigm to one of the most toxic and economically fraught corners of the recycling world.

The implications reach beyond the laboratory. Antimony supply is concentrated in a few countries, and the metal is essential not only for flame retardants but also for semiconductors, photovoltaics and military applications. Recovering it from e-waste at high purity could reduce dependence on primary mining while simultaneously detoxifying a waste stream that currently ends up in landfills or informal recycling operations where brominated pollutants threaten workers and ecosystems. A US provisional patent application on the Sb and Br recovery process has been filed by Rice University, and the team notes that the approach provides a rapid, integrated route for sustainable end-of-life management of flame-retardant plastics. As electronic waste volumes continue to climb worldwideFlash Joule heating turns toxic e-waste plastics into antimony resource in seconds.{

Subject of Research: Simultaneous antimony recovery from and debromination of flame-retardant electronic-waste plastics

Article Title: Simultaneous antimony recovery from and debromination of flame-retardant electronic-waste plastics

Article References: Ye, L. H., Cheng, Y., Silva, K. J., Xu, S., Zhu, H., Aina, O., Viscomi, N. L., Chen, S., Seguron, P., Liu, Q., Sharp, J., Cheng, L., Tang, J. C., Abdel Nour, R. S., Li, B., Si, T., West, J. G., Yakobson, B. I., Zhao, Y., & Tour, J. M. (2026). Simultaneous antimony recovery from and debromination of flame-retardant electronic-waste plastics. Nature Chemical Engineering. https://doi.org/10.1038/s44286-026-00455-3

Image Credits: AI Generated

DOI: 10.1038/s44286-026-00455-3

Keywords: flash Joule heating, antimony recovery, debromination, electronic waste, flame retardants, ABS plastics, critical metals, recycling, life-cycle assessment, hydrodebromination, Nature Chemical Engineering, Rice University

The study addresses a persistent blind spot in climate accounting. While many countries have detailed inventories for energy, transport, and industry, the waste sector in developing economies is often assessed only through fragmented local studies. Rapid population growth, accelerating urbanization, and industrial expansion have driven municipal solid waste generation sharply upward in such countries, and the waste stream itself is typically rich in organic material. When that organic fraction decomposes in landfills under anaerobic conditions, methanogenic bacteria convert it into methane, a greenhouse gas with a global warming potential far exceeding that of carbon dioxide over a century-long horizon. Under landfill-dominant disposal systems, the authors note, this methane formation becomes the single largest driver of the sector’s climate footprint.

To capture how policy choices ripple through decades of waste infrastructure, the researchers constructed four alternative scenarios spanning 2020 to 2040. The baseline scenario assumes continuation of current practice, with landfill disposal remaining the dominant route for municipal waste. The alternatives progressively layer in the interventions that dominate modern waste policy debates: landfill gas recovery systems that capture methane before it escapes, expanded recycling and composting programs that divert biodegradable material away from disposal altogether, and controlled waste-to-energy implementation that burns residual waste under regulated conditions while generating electricity. Each scenario was evaluated not only for its emissions trajectory but also for its economic and environmental implications, allowing the authors to weigh mitigation against cost.

The technical backbone of the analysis draws on internationally standardized estimation methods, including the 2006 IPCC guidelines for national greenhouse gas inventories and the supplementary guidance developed under the Kyoto Protocol. Methane generation from landfills depends on the quantity and composition of deposited waste, the moisture conditions within the landfill, and the decay rate of the organic fraction, all of which the model tracks over time. Emissions are expressed in tonnes of CO2 equivalent, the common currency of climate accounting that converts methane, nitrous oxide, and other gases into the amount of carbon dioxide that would produce the same warming effect. The authors also incorporated national statistics, including data from Iran’s Statistical Yearbook, alongside population projections to drive waste generation estimates across the study period.

The headline finding is the sheer spread of possible futures. Under the baseline, in which landfill disposal continues unchallenged, annual emissions from the waste sector climb toward the upper end of the range, roughly 21 million tonnes of CO2 equivalent per year, because uncontrolled methane generation from decomposing organic waste continues unchecked. At the opposite extreme, the integrated mitigation scenario, labeled S4 in the study, delivers the greatest reduction of any pathway, cutting approximately 1.8 million tonnes of CO2 equivalent relative to the alternatives. S4 achieves this by combining diversion of biodegradable waste away from landfills with improved recycling, expanded composting, and energy recovery systems, effectively attacking methane formation at its source while extracting value from the residual stream.

Perhaps the most consequential result, however, lies beneath the national totals. When the researchers disaggregated their projections to the provincial scale, they found that mitigation effectiveness varies substantially across Iran’s territory. Provinces with high waste generation achieve the largest absolute reductions under the intervention scenarios, simply because there is more material available to divert, capture, or convert. This spatial heterogeneity carries a direct policy implication: a uniform national strategy would leave significant reductions unrealized in some regions while over-investing in others. The authors argue that region-specific implementation, calibrated to local waste volumes, composition, and infrastructure, is essential for maximizing the climate return on mitigation spending.

The findings sit within a growing international literature on waste-sector climate mitigation. Comparable scenario studies have been conducted for Attica in Greece, for South Korea, for Chinese cities, and for Turkish landfill systems, each confirming that the choice between disposal and diversion dominates the sector’s emissions trajectory. Research on Chinese cities has documented decreasing greenhouse gas emissions from the municipal solid waste sector where diversion policies took hold, while assessments of Thai waste-to-energy facilities and São Paulo’s energy recovery potential illustrate how middle-income economies have monetized waste as a fuel. The Iranian study extends this evidence base by pairing national-scale forecasting with provincial granularity, a combination the authors identify as a clear gap in the existing literature.

The economic dimension of the analysis matters as much as the environmental one. Landfill gas recovery, composting, and waste-to-energy are not merely emission controls; they are revenue-generating infrastructure. Captured landfill gas can fuel electricity generation, compost displaces synthetic fertilizer demand, and energy-from-waste plants feed power grids. Studies cited in the paper, including assessments of landfill gas electricity generation in Korea using the Long-range Energy Alternative Planning model and comparative reviews of electricity generation potential across waste management technologies, underscore that the most effective climate strategies for the waste sector are frequently those that also produce marketable outputs. The Iranian results reinforce this pattern, with the integrated scenario delivering both the deepest emission cuts and enhanced energy recovery potential.

For Iran specifically, the stakes are amplified by the country’s broader climate commitments and its exposure to the impacts of a warming region. The waste sector represents one of the more tractable emission sources, since the underlying chemistry of methane formation is well understood and the intervention technologies are mature and widely deployed elsewhere. What the study demonstrates is that the difference between a passive future and an active one is enormous: a factor of roughly fifteen separates the high-emission baseline from the low-emission integrated pathway. Closing that gap requires diverting biodegradable waste from landfills at scale, building out composting and recycling capacity, deploying landfill gas capture, and introducing controlled waste-to-energy where appropriate, all tailored to the waste profile of each province.

The study’s provincial results offer a roadmap for that tailoring. High-waste provinces, which contribute the largest absolute emission reductions under the integrated scenario, are natural candidates for early infrastructure investment, while regions with smaller waste streams may achieve better returns through targeted composting and recycling programs rather than capital-intensive energy facilities. As developing economies worldwide grapple with rising waste volumes and tightening climate targets, the Iranian case study provides a quantified template: the emissions trajectory of a nation’s waste sector is not an inevitability of growth, but a direct consequence of the management choices made today.

Subject of Research: Forecasting greenhouse gas emissions from municipal solid waste management in Iran under alternative scenarios from 2020 to 2040

Article Title: Forecasting greenhouse gas emissions from municipal waste management under alternative scenarios: a country-level study

Article References: Abbasi, M., & Mehrdad, S. M. (2026). Forecasting greenhouse gas emissions from municipal waste management under alternative scenarios: a country-level study. Clean Technologies and Environmental Policy, 28(11), Article 274. https://doi.org/10.1007/s10098-026-03571-z

Image Credits: AI Generated

DOI: 10.1007/s10098-026-03571-z

Keywords: greenhouse gas emissions, municipal solid waste, methane, landfill gas recovery, waste-to-energy, composting, recycling, Iran, climate mitigation, scenario analysis, CO2 equivalent, waste management

The study is grounded in the Social Ecological Model, a framework that holds that individual behavior is shaped not only by personal knowledge but also by interpersonal, community, institutional, and policy-level factors. In the context of plastic waste, this means that household recycling is not simply a matter of personal willingness but depends on enabling conditions such as segregation bins, educational campaigns, incentive programs, and regulatory enforcement. The researchers argue that understanding these multiple interacting levels is essential for designing interventions that actually work, rather than relying on awareness campaigns alone.

Plastic pollution is a particularly acute problem in the region. Sub-Saharan Africa’s annual plastic importation and production are estimated at 117.6 million metric tons, with roughly 80 percent ending up as solid waste. In Ghana alone, about 8.2 billion sachets of drinking water are consumed each year, and improper disposal has resulted in approximately 86 percent of the country’s plastic waste clogging stormwater drains, rivers, and streams, with an estimated 250,000 metric tons eventually reaching the Atlantic Ocean. Sierra Leone imported 9 million kilograms of plastic in 2019 alone, 92 percent of which came from Ghana, illustrating the regional nature of the problem.

The survey found that households across all three countries generate similar forms of plastic waste, dominated by sachet bags, plastic bottles, shopping bags, food packaging, and detergent packs. In Ghana, more than half of respondents reported generating all five waste types, reflecting the country’s high consumption of packaged goods. When asked how they dispose of plastic waste, the most common practice in all three countries was dumping it in bins, with burning as the second most frequent method. The persistence of open burning, the researchers note, has serious implications for air quality, greenhouse gas emissions, and human health, and reflects deficiencies in waste collection services and the absence of alternative disposal mechanisms.

One of the most striking findings concerns knowledge of plastic recycling symbols. The Society of the Plastics Industry introduced a coding system in 1988 that places a numbered triangle on most plastic products to indicate the type of polymer, ranging from PETE (polyethylene terephthalate) used in beverage bottles to HDPE, PVC, LDPE, PP, PS, and a miscellaneous category labeled OTHER. Despite the high educational attainment of the sample, with 96.3 percent of respondents holding tertiary qualifications, awareness of these symbols was generally low. Knowledge of the PETE symbol was comparatively higher, particularly in Zambia at 51.35 percent and Ghana at 34.45 percent, while Sierra Leone recorded just 12.28 percent. Awareness of PS and OTHER symbols was particularly poor, with roughly one-tenth of respondents reporting knowledge of these classifications.

Chi-square analysis revealed statistically significant differences among the three countries in knowledge of the PETE and HDPE symbols, suggesting that exposure to recycling activities and public awareness campaigns varies across national contexts. However, knowledge of PVC, LDPE, PP, PS, and OTHER symbols did not differ significantly, indicating that poor awareness of less common polymer classifications is a shared challenge across the region. The researchers interpret this as evidence that formal education does not necessarily translate into technical understanding of recycling systems, and that environmental literacy depends more on exposure to recycling information than on educational attainment alone.

The study also examined the role of economic incentives and institutional support. A significant majority of respondents, 77.31 percent, had never received rewards in the form of money or household goods in exchange for their plastic waste, and only 8.33 percent had been given dustbins by authorities for plastic waste segregation. Furthermore, 85.19 percent of respondents had never received visits from regulators or officials to educate them about waste segregation. These findings point to weak institutional engagement and largely absent incentive mechanisms within household recycling systems across all three countries.

Despite these barriers, respondents expressed broad support for potential interventions. Overall, 74.54 percent believed that measures such as household goods exchange programs, provision of segregation buckets, and periodic visits by officials would effectively increase household waste segregation. Notably, the Kruskal-Wallis H test found no statistically significant difference among the three countries in perceptions of intervention effectiveness, suggesting that households across different national contexts share broadly similar views on what would help. The researchers cite previous work in Mozambique, where providing sorting bins and conducting periodic home visits significantly boosted household waste segregation, as evidence that such approaches can succeed when implemented.

The study’s authors conclude that improving household plastic waste segregation in Ghana, Sierra Leone, and Zambia requires integrated interventions that combine public education, provision of segregation facilities, incentive schemes, and strengthened regulatory support. They argue that policies aimed at improving plastic waste management should be tailored to country-specific conditions rather than adopting a uniform approach across Sub-Saharan Africa, given the variations in socio-economic and institutional contexts observed. They also note that introducing deposit-refund systems, plastic buy-back schemes, and household goods exchange programs could increase the supply of recyclable materials and strengthen the circular economy in the region.

The research contributes to a growing body of literature on household plastic waste management in developing countries and provides empirical evidence to support the design of sustainable waste management policies. By demonstrating that household behavior is shaped by interactions between individual awareness and institutional support systems rather than by personal attitudes alone, the findings underscore the need for coordinated efforts addressing behavioral, institutional, and infrastructural barriers simultaneously if Sub-Saharan Africa is to transition from a linear take-make-dispose model toward a functioning circular plastic economy.

Subject of Research: Household plastic waste segregation, disposal practices, and recycling awareness in Ghana, Sierra Leone, and Zambia

Article Title: Comparative assessment of household plastic waste segregation, disposal practices, and recycling awareness in Ghana, Sierra Leone, and Zambia

Article References: Afeliga, E., Essuman, M. A., Hamidu, I., Asamoah, K., Munyenyembe, H., Odis, A. I., & Lavalie, E. D. M. (2026). Comparative assessment of household plastic waste segregation, disposal practices, and recycling awareness in Ghana, Sierra Leone, and Zambia. Frontiers in Sustainability, 7, Article 1816953. https://doi.org/10.3389/frsus.2026.1816953

Image Credits: AI Generated

DOI: 10.3389/frsus.2026.1816953

Keywords: plastic waste, recycling, household segregation, Sub-Saharan Africa, circular economy, waste management, Ghana, Sierra Leone, Zambia, recycling symbols, economic incentives, Social Ecological Model

The research, led by Qindong Yang of Tsinghua University with colleagues from the National Institute for Environmental Studies in Japan, the University of Southern Denmark and Tianjin and Nankai Universities, is the first to couple province-resolved fleet projections for China with explicit battery degradation modelling and dynamic material flow analysis. That combination matters, because most previous assessments of shared mobility’s resource benefits assumed batteries simply last a fixed number of years. In reality, a shared electric car can be on the road for many more hours a day than a privately owned one, racking up charge cycles and deep discharges that age its cells far faster than the average owner’s vehicle would.

The team’s modelling shows just how consequential that distinction is. For vehicles equipped with lithium nickel manganese cobalt oxide batteries, the high-energy chemistry known as NMC811 that many manufacturers favour for long-range driving, shared mobility was expected to save between 5.3 and 8.1 million tonnes of cumulative lithium demand by 2060 under static lifetime assumptions. When degradation was factored in realistically, those savings shrank to between 2.6 and 4.7 million tonnes. In other words, the faster turnover of degraded shared-fleet batteries could consume a large share of the raw material reductions that car sharing was supposed to deliver.

Not every chemistry suffers equally, however. The study finds that more durable batteries, notably lithium iron phosphate, the chemistry that dominates China’s mass-market electric fleet, and lithium nickel cobalt aluminium oxide cells, can preserve or even amplify the material savings of shared mobility. This creates what the authors describe as a chemistry-dependent dividend: the environmental case for sharing vehicles is only as strong as the longevity of the batteries inside them. A shared fleet built on robust, degradation-resistant packs delivers genuine resource relief, while one built on energy-dense but fragile cells may simply burn through minerals at nearly the same pace as private ownership.

Behind these numbers lies a subtle temporal trap that the researchers call a trade-off in timing. Intensive use accelerates battery retirement, which sounds bad but has a hidden benefit: retired packs feed the recycling stream sooner, boosting the supply of secondary materials recovered from end-of-life batteries. At the same time, many circular-economy strategies route retired electric vehicle batteries into second-life applications, typically stationary grid storage, before they are finally recycled. The study shows that this detour delays recycling, locks secondary material supply to vehicle manufacturing timelines, and increases near-term demand for newly mined lithium and other critical minerals. The very strategy designed to squeeze extra value from spent batteries can, paradoxically, deepen short-term dependence on primary resources.

The scale of the analysis is one of its distinguishing strengths. Rather than treating China as a single homogeneous market, the team resolved their projections at the provincial level, capturing the enormous variation in climate, driving conditions and use intensity across the country. Batteries in hot southern provinces degrade faster than those in cooler northern regions, and the duty cycles of ride-hailing fleets in megacities differ sharply from those of private cars in smaller urban areas. By overlaying these regional degradation patterns on dynamic material flow models, the researchers could track how lithium, cobalt and nickel circulate through the Chinese fleet year by year, distinguishing between material locked in operating vehicles, material awaiting recycling and material returning from the scrap stream.

Dynamic material flow analysis, the methodological backbone of the study, treats the vehicle fleet as a kind of reservoir of embodied metals. Batteries enter that reservoir at manufacturing and exit at end of life, where they can either be recycled back into the production loop or diverted into second-life storage before eventual recovery. The timing of these flows determines whether a closed-loop system, in which recycled material fully satisfies new battery demand, arrives in time to relieve mining pressure. The study maps the conditions under which China’s battery system achieves that closed loop, and finds that degradation assumptions shift the timing substantially. Shared mobility with fast-degrading NMC811 packs floods the recycling pipeline earlier but with a much larger total volume of batteries that must be replaced, while durable chemistries slow the flow but reduce cumulative demand overall.

The findings carry immediate relevance for policy and industry strategy, both in China and beyond. China’s Ministry of Industry and Information Technology has already established standards for the comprehensive utilisation of waste electric vehicle batteries, and the country’s dominance in lithium-ion battery recycling gives it a head start on circular supply chains. But this study suggests that policy cannot treat recycling, second-life deployment, battery chemistry selection and mobility models as independent levers. A fleet-planning decision as mundane as whether ride-hailing vehicles use lithium iron phosphate or NMC811 cells propagates through decades of material demand, recycling capacity needs and import dependence. The authors argue that accounting for battery degradation is therefore critical to aligning shared mobility, battery choice and circular strategies with transport decarbonization goals.

There is also a broader lesson about how the clean energy transition is modelled. Life cycle assessments and material demand projections frequently rely on static assumptions about product lifetimes, an approach that is computationally simpler but can misrepresent systems in which usage intensity fundamentally alters durability. The battery community has made rapid progress on the science of degradation, from physics-based ageing models to machine-learning approaches that can predict cycle life from early discharge data, and this study demonstrates how powerful it is to embed that understanding directly into resource assessments. The same logic likely applies to other heavily used clean technologies, from grid-scale storage batteries to hydrogen fuel cells in commercial fleets, where duty cycles differ dramatically from laboratory baselines.

For consumers and investors watching the electric vehicle market, the takeaways are tangible. Durable chemistry choices, thoughtful thermal management and realistic usage projections all shape how much mining the mobility transition ultimately requires. Shared mobility remains a valuable tool for cutting emissions and materials demand, but the new analysis makes clear that it is not automatically a resource panacea. Whether car sharing delivers its promised material dividend depends on batteries that can endure the punishing schedules of shared fleets, on recycling systems timed to collect retired packs without unnecessary detours, and on planners who treat degradation not as an afterthought but as a first-order variable in the circular economy of transport.

Subject of Research: Material demand and circularity implications of battery degradation in shared electric mobility in China

Article Title: Material circularity implications of battery degradation in shared electric mobility

Article References: Yang, Q., Xu, G., Chen, W., Tong, D., & Cao, Z. (2026). Material circularity implications of battery degradation in shared electric mobility. Nature Sustainability. https://doi.org/10.1038/s41893-026-01969-7

Image Credits: AI Generated

DOI: 10.1038/s41893-026-01969-7

Keywords: shared mobility, battery degradation, lithium, NMC811, lithium iron phosphate, recycling, second-life batteries, material flow analysis, critical minerals, China, electric vehicles, circular economy

The technology, called Wax Foam 3D Printing (WF3DP), deliberately fuses additive and subtractive manufacturing rather than choosing between them. A robotic extrusion system deposits wax foam close to the final geometry, exploiting the material efficiency of 3D printing, while a five-axis CNC milling machine then cuts the printed preform to the precise contour and surface quality that concrete casting demands. The key innovation lies in the material itself: a wax-air composite in which roughly 20 percent of the volume is air, foamed mechanically without any chemical change. Because the wax can be remelted, filtered, and re-foamed indefinitely, the approach supports a closed-loop material cycle at the process level, not merely as an aspiration.

The hardware is substantial. The custom WF3DP unit integrates a heated reservoir holding molten wax at about 90 degrees Celsius, a mechanical foaming unit that whips filtered wax together with air and pre-cools the mixture into a homogeneous semi-solid foam, and a temperature-controlled delivery hose feeding a 12-millimetre extrusion nozzle. The print head is carried by an industrial six-axis KUKA robot with a working volume of 1.6 by 1.2 by 2 metres. Immediately before extrusion, the foam passes through a localized cooling stage regulated to within one degree Celsius, bringing it slightly below its freezing point so that a partially crystallized microstructure gives the extrudate dimensional stability and clean layer formation.

Throughput is impressive for a feasibility study. Stable deposition was achieved at rates of up to 28.5 kilograms per hour, and in the case study roughly 250 kilograms of wax foam were deposited in a continuous print lasting 8 hours and 45 minutes. The printed block measured about 1050 by 1550 by 500 millimetres, including a 20-millimetre offset for milling. Cooling from 65 to 25 degrees Celsius took 3 days and 21 hours, a dramatic improvement over the more than two weeks expected for a comparable solid wax block, whose enormous thermal mass must dissipate its heat slowly.

The material choice proved decisive. The team characterized a new formulation, Tudastar wax, against the ConFormWax (CFW) used in a decade of earlier wax formwork research at Braunschweig. CFW wax has a freezing range of only 62 to 66 degrees Celsius and begins softening well below it; in earlier trials with massive elements up to 1.5 tonnes, hydration heat from curing concrete had softened and partially melted the formwork surface, preventing reuse. Tudastar wax freezes at approximately 81 degrees Celsius, providing a much larger thermal margin. In compressive tests, solid Tudastar wax reached 4.69 newtons per square millimetre, and foaming with 20 percent air reduced its strength by only 6 percent, to 4.40, whereas foamed CFW wax lost 48 percent of its strength. Foamed Tudastar wax therefore carried 2.7 times the load of foamed CFW wax.

Temperature-dependent testing revealed how much of that strength evaporates as the wax warms. Printed Tudastar foam specimens softened from 3.59 newtons per square millimetre at room temperature to 3.03 at 35 degrees and 1.72 at 45 degrees, less than half the room-temperature value, with the failure mode shifting from partly brittle cracking to ductile deformation. Yet even at 45 degrees, the printed foam retained the room-temperature strength of foamed CFW wax, and the measured formwork temperatures during the case study, peaking at 40 to 47 degrees near the wax-concrete interface, stayed well within Tudastar’s thermal margin. Surface-energy measurements using the Owens-Wendt-Rabel-Kaelble method showed Tudastar wax to be almost entirely nonpolar, with a polar component of just 0.25 millinewtons per metre, suggesting favourable demoulding behaviour without release agents.

The full-scale case study put these properties to the test. A cooperating precast manufacturer commissioned a customized radial seating step, a two-step double-curved element with an inner radius of 115 centimetres and an outer radius of 155 centimetres, specified in fair-faced concrete class SB3, a demanding architectural surface standard. The conventional reference formwork had been built manually by a single carpenter in about 1.5 days from plywood and modelling foam, designed for up to 15 casting cycles but reused for only seven before being discarded as non-recyclable waste. The wax route instead printed a near-net-shape preform, scanned it in 3D, and finish-milled it in about 1.5 hours on a five-axis machine.

The print was not flawless. Edges warped upward by as much as 50 millimetres, producing a bowl-shaped deformation, and cracks developed between deposited strands where interlayer bonding proved insufficient. During machining, delamination occurred along layer interfaces, requiring local repair with molten wax, infrared reheating to densify the surface, and remachining. These defects matter because fine gaps between printed layers allowed cement paste and mixing water to penetrate by capillary action during casting, causing localized discoloration and an alternating rough and smooth texture on the demoulded concrete. The element reproduced its complex radial geometry accurately with sharply defined edges and no adhesion damage, but it met the SB3 surface requirements only in part and would need remedial treatment to comply fully.

Demoulding after roughly 23 hours of curing confirmed the expected release behaviour: no release agent was applied to the wax, and no concrete residue or adhesion was detected, though wooden wedges and mechanical force were needed to initiate separation, causing localized surface damage that prevented direct reuse of the formwork for a second casting. The team instead closed the material loop at process level: the used formwork was completely remelted in an 8-kilowatt tank, pumped through fine filtration units to remove concrete particles, re-foamed, and printed into new formwork elements for ongoing research. Earlier investigations had already shown CFW wax withstanding more than 200 remelting cycles without noticeable property changes, and comparable behaviour is expected for Tudastar wax provided oxidation is avoided.

The resource accounting is striking. Producing a formwork element of comparable size by the solid wax block route would have required roughly 1.13 tonnes of wax, most of it machined away without ever contributing to the casting surface. The near-net-shape printed route consumed about 250 kilograms, an approximately 80 percent reduction. The authors estimate that with structural infill patterns and dedicated slicing software, printing time could fall to about 2.5 hours and cooling to roughly one day, cutting the waiting time until the formwork is available to about one-tenth of the solid-block route. Labour input, currently high at around 17 hours including path planning and repair, is expected to become comparable to conventional routes once automation matures. The study identifies interlayer bonding, warpage control, geometric accuracy, surface quality, and damage-free demoulding as the principal hurdles between this prototype and an industrial-ready technology, but it establishes something concrete: a formwork that is printed, milled, cast, and melted down again, within a largely digital process chain powered by on-site solar energy.

Subject of Research: Materials science

Article Title: A novel formwork technology based on wax foam 3D printing and CNC milling

Article References: Jonischkies, S., Mainka, J., Kloft, H., Diesslin, R., & Hack, N. (2026). A novel formwork technology based on wax foam 3D printing and CNC milling. Frontiers in Built Environment, 12, Article 1934051. https://doi.org/10.3389/fbuil.2026.1934051

Image Credits: AI Generated

DOI: 10.3389/fbuil.2026.1934051

Keywords: 3D printing, concrete, formwork, recycling, CNC milling, circular economy, novel, technology, based, foam, printing, milling

The study, conducted by Sibongangani Khonelihle Mngomezulu of the Department of Built Environment at Central University of Technology in Bloemfontein, surveyed 255 households across three deliberately contrasting neighbourhoods: Walmer-E as an informal, low-income township; Summerstrand as a relatively affluent, formally serviced suburb; and Gqeberha Central as a mixed residential-commercial urban core. With an 84 percent response rate from 303 targeted households, the survey achieved unusually strong participation for household-level waste research. Respondents were asked about how often they generated different waste types, how they stored and disposed of materials, what challenges they perceived in their local waste systems, and whether they were aware of existing municipal policies.

The statistical architecture of the study was rigorous. Mngomezulu applied Pearson’s chi-square tests to check whether differences in waste-generation frequency across the three areas were real or merely sampling noise, reporting effect sizes with Cramér’s V. For perception data, Welch’s analysis of variance was used because group variances and sample sizes differed, followed by Games-Howell post hoc comparisons to pinpoint which area pairs differed significantly. Principal component analysis, with a Kaiser-Meyer-Olkin value of 0.936 and a highly significant Bartlett’s test, distilled 26 Likert-scale items into four underlying dimensions of sustainable waste management: governance, social behaviour, economic feasibility, and education and knowledge.

The waste-generation findings are striking in their specificity. In Gqeberha Central, 80 percent of respondents reported generating plastics daily — the highest single frequency recorded anywhere in the study. Organic waste was also generated daily by 57.6 percent of Central residents and 53.7 percent of Summerstrand residents. Walmer-E showed a fundamentally different rhythm: plastics were generated monthly by 54.5 percent of respondents, old clothes by 59.1 percent, glass by 60.2 percent, and metal cans by 52.3 percent. This monthly concentration of durable and recyclable streams suggests that Walmer households consume and discard differently, potentially reflecting lower purchasing frequency, different storage capacity, or distinct patterns of reuse before disposal.

Chi-square tests confirmed that these cross-area differences were statistically robust for the four waste streams that met expected-frequency criteria. Plastics produced a chi-square value of 188.28 with a Cramér’s V of 0.609; nappies and wipes reached 216.25 with a V of 0.652; glass scored 179.59 with V = 0.597; and cans and metals registered 164.17 with V = 0.568. All four exceeded the conventional threshold of 0.5 for a large effect, meaning that residential area alone explains a substantial portion of the variation in how often households generate these materials. Sparse cells prevented reliable testing for specialised streams such as hazardous waste, e-waste, garden waste, and construction debris, which the study treats descriptively rather than inferentially.

Collection systems told a more nuanced story. Routine household waste was generally well served: 69.4 percent of respondents reported weekly collection, 22.0 percent daily, and only 1.2 percent said their waste was never collected. When collections were missed, service typically resumed within a week (32.5 percent of respondents) or a fortnight (31.0 percent). But the picture changed dramatically for specialised waste. In both Walmer and Summerstrand, identical numbers of respondents — 38 for hazardous waste, 61 for batteries, 63 for electronic waste, 58 each for garden and construction waste — reported using alternative disposal methods outside the formal municipal system. In Gqeberha Central, old clothes (68 respondents), garden waste (58), and construction waste (58) were similarly diverted into informal channels.

Perceived challenges varied enormously by area, and the pattern is telling. Gqeberha Central recorded the highest mean scores across nearly every challenge dimension: diminished tourism at 4.62 on a five-point scale, clogged drains at 4.46, dust and litter at 4.31, inadequate awareness programmes at 4.28, and cultural and traditional practices at 4.27. Walmer followed with clogged drains at 4.43 and dust and litter at 4.28. Summerstrand, by contrast, reported greenhouse gas emissions as its top concern at just 2.73, with clogged drains scoring a mere 1.84 and diminished tourism 1.45. The gap between Central’s 4.62 and Summerstrand’s 1.45 on tourism impacts — a spread of more than three full scale points — illustrates how differently the same municipal waste system is experienced depending on where one lives.

Perhaps the most alarming finding concerns public awareness. When asked whether they knew about existing waste-management systems or policies in Nelson Mandela Bay, 68.2 percent of respondents said they were unaware. Only 30.2 percent reported any awareness, and 1.6 percent of responses were missing. This knowledge gap persisted across all three areas regardless of income or education level, suggesting that the problem lies not in individual households but in the communication infrastructure connecting municipal authorities to residents. The study links this awareness deficit to reduced participation in recycling, waste separation, and compliance with regulations, and points to South African research showing that indiscriminate dumping correlates strongly with low awareness and limited service access.

The four-factor model derived from principal component analysis revealed that governance dominates the sustainable waste-management landscape, explaining 51.68 percent of variance with an eigenvalue of 13.437 and a Cronbach’s alpha of 0.933 — exceptional internal consistency for a social science construct. Social behaviour followed at 8.25 percent of variance, economic feasibility at 7.57 percent, and education and knowledge at 4.44 percent. Welch’s ANOVA confirmed that all four factors differed significantly across the three areas, with eta-squared values of 0.397 for governance, 0.494 for social behaviour, 0.455 for economic feasibility, and 0.347 for education and knowledge — all large effects. Games-Howell comparisons showed that every pair of areas differed significantly on governance and economic feasibility, while for social behaviour, Walmer and Summerstrand did not differ significantly from each other (p = 0.294), indicating that area differences are construct-specific rather than uniform.

The study’s five-year review of municipal waste-quantity data exposed a deeper governance crisis beneath the household findings. Published figures for Nelson Mandela Bay are not comparable across years: the 2019/20 estimate of 571,482 tonnes was a planning figure for two landfill sites, while the 2020/21 figure of 285,652 tonnes reflected waste received at licensed landfills. No comparable figure exists for 2021/22 because no landfill audit was conducted during the COVID-19 outbreak. The 2022/23 total of 191,670 tonnes covers only seven months due to non-functional weighbridges and a backlog in manual records. Reported waste diversion collapsed from 1,463 tonnes in 2022/23 to just 463 tonnes in 2023/24 — a 68.4 percent decline — though the absence of a comparable landfill denominator makes it impossible to determine whether this reflects genuine contraction in recovery activity or simply deteriorating record-keeping. Either interpretation, the study argues, demands urgent attention: weak recovery means valuable organic material, plastics, paper, glass, and metals are lost to disposal, while weak recording makes it impossible to recognise the contributions of informal reclaimers and private-sector recyclers.

Mngomezulu’s recommendations are deliberately area-specific rather than uniform. For Walmer-E, the study proposes scheduled dry-recyclables collection, neighbourhood buy-back and repair hubs, community composting, and accessible drop-off points, with indicators tracking kilograms of recyclables per household per month and income flowing to local enterprises. For Summerstrand, two-stream kerbside separation of dry recyclables and residual waste, home and community composting, and extended producer responsibility-supported collection of packaging and e-waste are recommended. For Gqeberha Central, the study calls for high-frequency separate collection, organics services for food businesses, staffed recovery points, and formal integration of informal reclaimers, with indicators measuring tonnes recovered per day, overflow incidents, drain blockages, and reclaimer income and safety compliance. Across all three areas, the study urges the municipality to adopt a current Integrated Waste Management Plan with ward-level targets, repair and calibrate landfill weighbridges, digitise daily tonnage records, publish comparable annual data, and respond to the 68.2 percent awareness gap through multilingual campaigns, schools, ward committees, and clear service calendars.

Subject of Research: Comparative analysis of household municipal solid waste management practices and perceptions across income groups in Nelson Mandela Bay Municipality, South Africa

Article Title: Municipal solid waste management systems in Nelson Mandela Bay Municipality: a comparative analysis across diverse income groups

Article References: Mngomezulu, S. K. (2026). Municipal solid waste management systems in Nelson Mandela Bay Municipality: a comparative analysis across diverse income groups. Frontiers in Sustainability, 7, Article 1941833. https://doi.org/10.3389/frsus.2026.1941833

Image Credits: AI Generated

DOI: 10.3389/frsus.2026.1941833

Keywords: municipal solid waste, circular economy, Nelson Mandela Bay, South Africa, waste management, recycling, income inequality, governance, public awareness, waste generation, urban sustainability, household survey