A team led by Xuejiao Tang at Nankai University has now reported a solution that takes aim at one of the most persistent practical obstacles in this field: the difficulty of using highly active cobalt-based catalysts without losing them to the water being treated. Powdered cobalt catalysts are exceptionally effective at activating peroxymonosulfate, a common oxidant precursor used in advanced oxidation processes, but their fine particle size makes them nearly impossible to separate after treatment and raises the prospect of dissolved cobalt escaping into the environment. The researchers’ answer is a millimeter-scale magnetic carbon bead designated CoNC@cPAN/rGO-800, a material engineered to combine catalytic performance with physical recoverability.

The beads are built from three complementary components. A polyacrylonitrile-derived carbon framework forms the structural backbone, giving each bead its mechanical integrity and millimeter dimensions. Reduced graphene oxide is woven into this framework, contributing electrical conductivity and a distinctive internal architecture. Finally, cobalt-containing active sites, derived from a cobalt-containing zeolitic imidazolate framework precursor, are distributed throughout the material. The precursor mixture of the zeolitic imidazolate framework, polyacrylonitrile, and graphene oxide was calcined under nitrogen at several different temperatures, and the resulting products were screened to identify the optimal synthesis conditions.

Characterization played a central role in understanding why the final material performs so well. The researchers deployed a full analytical arsenal, including electron microscopy, spectroscopic techniques, X-ray diffraction, surface-area analysis, electrochemical measurements, and density functional theory calculations. Together these methods revealed that the graphene-derived component generates a hierarchical honeycomb-like pore structure throughout each bead. This architecture serves two purposes at once: it exposes a large internal surface area populated by accessible cobalt sites, and it reduces electronic impedance across the material, facilitating the rapid electron transfer that peroxymonosulfate activation demands.

The degradation performance reported in the study is striking. Under optimized conditions, using just 0.1 grams per liter of catalyst and 0.1 grams per liter of peroxymonosulfate, the beads removed 100 percent of sulfamethoxazole present at 10 milligrams per liter within 20 minutes at neutral pH. Perhaps more importantly for real-world application, the catalyst retained complete degradation of the antibiotic across an exceptionally broad pH range from 2 to 11, all within 30 minutes. Reaction rates did slow somewhat under strongly acidic and strongly alkaline conditions compared with neutral or mildly alkaline settings, but the system never lost its capacity to fully eliminate the target compound.

Natural water constituents are often the downfall of laboratory-optimized oxidation systems, since dissolved organic matter and inorganic ions can scavenge reactive species before they reach their targets. The Nankai team tested this vulnerability directly. Humic acid and several common inorganic anions caused only modest inhibition of sulfamethoxazole degradation, suggesting a meaningful degree of resilience against the chemical complexity of actual wastewater. Bicarbonate, however, exerted a noticeably stronger suppressive effect, a finding the authors note should inform deployment planning in waters with high alkalinity. Encouragingly, additional experiments conducted in campus lake water, river water, and a laboratory-scale flow reactor indicated that the system retains practical activity beyond ultrapure laboratory solutions.

To uncover the chemistry driving such efficient oxidation, the researchers performed quenching experiments and electron paramagnetic resonance measurements. These identified four reactive species contributing to pollutant removal: hydroxyl radicals, sulfate radicals, superoxide radicals, and singlet oxygen. Probe-based quantification assigned contribution ratios of 36.3 percent for hydroxyl radicals, 27.3 percent for sulfate radicals, 19.5 percent for superoxide radicals, and 16.9 percent for singlet oxygen. The mechanistic picture that emerges is unusual and elegant: oxygen vacancies within the material convert dissolved oxygen into superoxide radicals, and these superoxide species then serve as a chemical bridge, activating peroxymonosulfate to generate additional radical species or combining with one another to produce singlet oxygen.

This superoxide-mediated pathway gives the beads a form of built-in synergy, linking abundant atmospheric oxygen directly into the oxidation cycle and reducing sole dependence on the added oxidant. The team also found evidence of spatially differentiated reactivity within each bead. Cobalt nanoparticles located near the outer shell activate peroxymonosulfate directly during the early stage of the reaction, while oxygen-vacancy-rich cobalt oxide in the bead core contributes increasingly during the later stage as reactants penetrate inward. Reduced graphene oxide underpins both phases by supporting electron transport and promoting the formation of the oxygen vacancies on which the acceleration strategy depends, explaining the markedly faster second-stage kinetics observed for the graphene-containing material.

Stability and recoverability, the very weaknesses that have limited powdered cobalt catalysts, are where the new material distinguishes itself most clearly. The beads maintained 82.4 percent sulfamethoxazole degradation after eight consecutive batch cycles, demonstrating robust reusability. Their saturation magnetization of 34.45 emu per gram allows straightforward magnetic recovery from aqueous suspensions with an external magnet, eliminating the filtration burdens associated with nanoparticle slurries. Cobalt leaching peaked at just 0.28 milligrams per liter during degradation, substantially below the leaching measured for a powdered cobalt control prepared from the same precursor, confirming that the carbon framework immobilizes the metal effectively. In a fixed-bed column configuration, the system maintained complete degradation over five cycles at a flow rate of 1 milliliter per minute, a result with direct implications for continuous-flow engineering.

Environmental safety considerations extended beyond the parent compound. The researchers detected degradation intermediates and applied ECOSAR predictive modeling to assess their aquatic toxicity, finding that most intermediates carry lower predicted acute and chronic toxicity than sulfamethoxazole itself. The authors are careful to note that such computational predictions do not replace direct toxicity testing. They are equally candid about the road ahead: long-term performance, regeneration requirements, the ultimate fate of cobalt, and treatment behavior in diverse full-scale wastewater matrices remain to be established. Future work is expected to examine extended continuous-flow operation, catalyst regeneration, treatment of mixed antibiotic contaminants, and direct biological assessment of transformation products. By optimizing bead dimensions, pore architecture, peroxymonosulfate consumption, and cobalt immobilization, the team hopes to demonstrate a practical balance between rapid oxidation, low secondary pollution, and scalable operation, bringing a laboratory breakthrough closer to the water treatment facilities where it could one day matter most.

Subject of Research: Graphene- and cobalt-doped magnetic carbon beads for peroxymonosulfate-activated degradation of sulfamethoxazole in water

Article Title: Magnetic carbon beads accelerate the breakdown of sulfamethoxazole

Article References: Magnetic carbon beads accelerate the breakdown of sulfamethoxazole. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: sulfamethoxazole, magnetic carbon beads, peroxymonosulfate, graphene, cobalt catalyst, superoxide radicals, water treatment, antibiotic degradation, oxygen vacancies, catalyst recovery, advanced oxidation, biochar

The research, published in Cleaner Engineering and Technology by a team from the Tecnológico Nacional de México led by Bethsabet Jaramillo-Sierra, tackles a contamination problem that spans the globe. Acetaminophen has been detected in wastewater and surface waters on nearly every continent, at concentrations ranging from tens of nanograms per liter in France and Canada to hundreds of micrograms per liter in Colombia and northern Mexico. Although each individual measurement may seem small, the compound’s sheer consumption volume, its availability over the counter, and its resistance to biological degradation mean it accumulates persistently in rivers, drinking water sources, and even treated effluents.

The concern is not merely the presence of the parent molecule. Acetaminophen is poorly biodegradable, so it passes through conventional treatment largely intact, and it has been linked in laboratory studies to genetic damage, oxidative lipid degradation, and liver injury in living organisms. Worse still, during some tertiary treatment steps the compound can transform into by-products that are more dangerous than the original drug, including 1,4-benzoquinone and N-acetyl-p-benzoquinone imine, a hepatotoxic metabolite capable of causing hepatic failure and necrosis. Any credible remediation strategy must therefore do more than hide the molecule; it must destroy it or convert it into harmless end products.

The Mexican team turned to advanced oxidation processes, or AOPs, a family of water treatment methods that operate at ambient temperature and pressure and rely on the generation of highly reactive chemical species, most notably the hydroxyl radical. This radical carries a higher oxidation potential than chlorine and reacts non-selectively with a broad range of organic pollutants, which makes it attractive for treating trace contaminants of many kinds. AOPs also avoid sludge production, do not require adsorbents that need controlled disposal, and can be driven by easily handled reagents such as ozone and hydrogen peroxide, with ozone generated on site from atmospheric air to reduce storage and transport costs.

The experimental apparatus was deliberately simple: a cylindrical stainless-steel reactor with an 11-watt ultraviolet lamp emitting at 200 to 280 nanometers, housed in a quartz tube, coupled to a 12-watt ozone generator and a recirculating reservoir. Synthetic solutions of acetaminophen at 100 milligrams per liter were treated for 60 minutes in 500-milliliter batches, with hydrogen peroxide added at doses of 5, 10, and 15 milligrams per liter. Degradation was tracked by ultraviolet-visible spectrophotometry, chemical oxygen demand was measured colorimetrically, and oxidation by-products were identified using gas chromatography-mass spectrometry following solid-phase extraction.

The results revealed a clear hierarchy of effectiveness. Ultraviolet light alone managed only about 11 percent degradation in an hour, primarily by photolyzing water molecules into hydroxyl radicals and hydrogen atoms, a process that accelerates around the 254-nanometer wavelength. Hydrogen peroxide alone reached roughly 27 percent at the highest dose. Ozone alone, attacking through both direct molecular oxidation and indirect decomposition into hydroxyl radicals, achieved 73 percent. Pairing ozone with ultraviolet light pushed the figure to 84 percent, because photolysis of dissolved ozone generates additional atomic oxygen, hydroxyl radicals, and even hydrogen peroxide in solution, creating multiple parallel destruction pathways.

The real breakthrough came when all three agents were applied simultaneously. The ozone-hydrogen peroxide combination, known as peroxone, promotes hydroxyl radical formation through the mutual reaction of the two oxidants, and adding ultraviolet irradiation on top of this triggered photolysis of both peroxide and dissolved ozone. Under these conditions, with an initial hydrogen peroxide concentration of just 5 milligrams per liter, the team achieved 99 percent acetaminophen degradation in 60 minutes. Notably, the study found an optimal peroxide dose: higher concentrations of 10 and 15 milligrams per liter actually performed worse over time, because excess peroxide and the hydroperoxyl radical it forms act as scavengers, consuming the very hydroxyl radicals that destroy the pollutant.

Chemical analysis confirmed that the combined treatment went beyond mere transformation. Carbon dioxide production rose steadily across the treatment combinations, peaking at 37 milligrams per liter for the triple system, evidence of genuine mineralization rather than simple conversion to other organics. Chemical oxygen demand removal reached 74 percent in the same configuration, compared with just 9 percent for ultraviolet light alone. Color measurements told a parallel story: untreated solutions stayed clear, ultraviolet treatment alone produced a pale carmine tint at 150 platinum-cobalt units as aromatic ring breakdown products accumulated, while the triple system yielded only a faint yellow at 5 units, indicating that even the colored intermediates were being further oxidized. Gas chromatography-mass spectrometry identified by-products dominated by carboxylic acid, ester, and alcohol structures arising from aromatic ring cleavage and recombination, and crucially, the team did not detect hydroquinone or 1,4-benzoquinone, suggesting these hazardous intermediates were themselves degraded during the process.

Energetically, the triple treatment also proved competitive. The researchers calculated the electrical energy per order, a standard metric describing the kilowatt-hours needed to reduce pollutant concentration by one order of magnitude per cubic meter, and obtained 23.00 kilowatt-hours per cubic meter for the peroxide-ozone-UV system, well below the 537 kilowatt-hours per cubic meter required for ultraviolet treatment alone and below several values reported in comparable literature. The estimated operating cost of the best configuration came to 5.04 US dollars per cubic meter, with ultraviolet irradiation dominating the energy bill, ozone generation second, and hydrogen peroxide contributing least. The degradation kinetics followed a pseudo first-order model, with rate constants rising as processes were combined, consistent with the theory that degradation depends primarily on pollutant concentration while oxidant doses remain effectively constant.

Finally, the team assessed whether the treated water was actually safer, using the germination of lettuce seeds as a biological toxicity screen. Untreated and lightly treated samples showed moderate toxicity, with ozone alone inhibiting germination by 40 percent, a sign that oxidative intermediates can be more harmful than the parent drug. But the full triple treatment reduced inhibition to 15 percent, close to the control level, demonstrating that synergistic oxidation both destroys the pollutant and neutralizes its residual toxic footprint. Taken together, the findings position the combined peroxide-ozone-UV process as an operationally simple, reproducible, and relatively inexpensive route to eliminating one of the world’s most ubiquitous pharmaceutical pollutants, though the authors note that complete mineralization would likely require longer treatment times or more intensified oxidative conditions to drive the remaining low-complexity organic by-products all the way to inorganic carbon.

Subject of Research: Degradation of the pharmaceutical pollutant acetaminophen in water using combined advanced oxidation processes involving ozone, hydrogen peroxide, and ultraviolet radiation.

Article Title: Acetaminophen degradation process applying a combination of oxidizing agents and ultraviolet radiation

Article References: Jaramillo-Sierra, B., Mercado-Cabrera, A., Ibañez-Olvera, M., Peña-Eguíluz, R., Rodríguez-Méndez, B. G., & López-Callejas, R. (2026). Acetaminophen degradation process applying a combination of oxidizing agents and ultraviolet radiation. Cleaner Engineering and Technology, 34, Article 101301. https://doi.org/10.1016/j.clet.2026.101301

Image Credits: AI Generated

DOI: 10.1016/j.clet.2026.101301

Keywords: acetaminophen, paracetamol, advanced oxidation processes, ozone, hydrogen peroxide, ultraviolet radiation, hydroxyl radicals, wastewater treatment, pharmaceutical pollution, water purification, mineralization, chemical oxygen demand

PFAS are synthetic chemicals that have been widely utilized since the 1940s in an array of consumer products, including waterproof clothing, Teflon cookware, and food packaging. Their unique properties, such as resistance to heat, grease, and water, have rendered them valuable for various applications. However, these same characteristics contribute to their environmental persistence, leading to their notorious nickname as “forever chemicals.” The cumulative presence of PFAS in our environment—including soil, water, and air—is alarming, as studies link these substances to serious health risks such as liver damage, developmental disorders, immune system disruption, and increased cancer risk.

As awareness of PFAS contamination grows, traditional cleanup methods have come under scrutiny for being inadequate and inefficient. The most common approaches often involve adsorption techniques where PFAS molecules adhere to materials like activated carbon or ion-exchange resins. However, these existing technologies suffer from significant limitations, including slow processing times, low removal efficiency, and the generation of secondary waste that necessitates further management. These deficiencies underscore the urgent need for alternative solutions that not only address contamination effectively but also minimize resultant waste.

The Rice University team, led by postdoctoral fellow Youngkun Chung and guided by distinguished professor Michael S. Wong, has responded to this challenge with an innovative solution: a remarkable layered double hydroxide (LDH) material composed of copper and aluminum. This novel compound, initially identified by Professor Keon-Ham Kim at Korea Advanced Institute of Science and Technology (KAIST), was further refined in Chung’s experiments, which revealed its unprecedented efficiency in capturing PFAS.

Surprisingly, this specific formulation of LDH has demonstrated PFAS adsorption capabilities surpassing those of traditional materials by over 1,000 times. By binding PFAS molecules rapidly and securely—removing them within minutes—the team has addressed one of the critical drawbacks of contemporary purification techniques. Furthermore, their LDH system functions at speeds approximately 100 times faster than commercial carbon filters, positioning it as a game changer in the realm of water treatment technologies.

The effectiveness of the LDH material can be attributed to its unique structural properties. The organized layers of copper and aluminum in conjunction with charge imbalances create an optimal environment for the binding of PFAS molecules. This intricate design facilitates not only swift capture but also the potential for large-scale application across various water treatment contexts, including municipal wastewater processing and remediation of contaminated industrial sites.

Testing the practicality of this technology, the research team evaluated the LDH in diverse water samples, including river water, tap water, and wastewater. The promising results from these assessments confirm the LDH material’s robust performance in multiple scenarios, paving the way for its implementation in real-world applications. The accomplished researchers have laid the groundwork for a sustainable solution that could revolutionize how PFAS-contaminated water is treated globally.

However, successfully capturing PFAS is only one side of the equation; the decomposition of these resilient chemicals is equally crucial for a comprehensive solution. To tackle this aspect, Chung worked alongside Rice’s professors Pedro Alvarez and James Tour to develop an effective technique that thermally decomposes the PFAS once they are captured by the LDH material. This method involves heating the saturated material with calcium carbonate, eliminating over half of the trapped PFAS while generating no harmful by-products. Significantly, this process also enables the regeneration of the LDH material, allowing it to be reused repeatedly without loss of efficacy.

Remarkably, preliminary evaluations indicate that this innovative system can successfully complete at least six cycles of capture and destruction, establishing it as the first known eco-friendly, sustainable method for PFAS remediation. The potential impact of such technology is monumental, not only providing a viable solution to the PFAS crisis but also exemplifying the power of scientific collaboration.

The research findings, published in the prestigious journal Advanced Materials, highlight the concerted efforts of a diverse team of scientists hailing from various institutions worldwide. The project has received invaluable support from multiple funding sources, including grants from the National Research Foundation of Korea and collaborations with noted organizations such as Saudi Aramco and the U.S. Army Corps of Engineers.

The excitement surrounding this breakthrough is palpable, as the researchers envision a future where their LDH-based technology could fundamentally change the approach to treating PFAS-contaminated water sources. The project’s success underscores the importance of international collaboration and innovation in the field of environmental science. Moving forward, further research and optimization of this technology may unlock even greater capabilities for ensuring safe and clean water for communities globally.

Given the current environmental landscape, a sustained focus on the challenges posed by PFAS is imperative. The development of economical, efficient, and sustainable technologies like the LDH system is critical in advancing our ability to confront these complex pollution challenges comprehensively. As research in this field evolves, the potential for transformative shifts in how we manage water quality and environmental health must remain a priority.

In conclusion, Rice University’s pioneering technology to capture and deconstruct PFAS signals a significant leap towards safeguarding our ecosystems and public health. The fusion of ingenuity and collaborative spirit displayed by the research team is an inspiring reminder of the capacity for science to address pressing global challenges and make a meaningful difference in our world.

Subject of Research: Eco-friendly Technology for Capturing and Destroying PFAS
Article Title: Regenerable Water Remediation Platform for Ultrafast Capture and Mineralization of Per- and Polyfluoroalkyl Substances
News Publication Date: 25-Sep-2025
Web References: https://doi.org/10.1002/adma.202509842
References: Detailed references are outlined in the article.
Image Credits: Advanced Materials and Rice University.

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