Pharmaceutical residues such as acetaminophen, cephalexin and levofloxacin are increasingly detected as emerging contaminants in aquatic environments. These compounds can enter wastewater through human use, disposal and excretion, while many treatment facilities are not specifically designed to eliminate them completely. Even when concentrations are low, persistent pharmaceutical molecules and their biologically active transformation products may contribute to ecological stress and the spread of antimicrobial activity in the environment. Photocatalysis offers one possible solution. In this process, a semiconductor absorbs light and generates energetic electrons and positively charged holes. These charge carriers can react with water and dissolved oxygen to produce highly reactive species, including hydroxyl radicals and superoxide radicals, which attack complex organic molecules and progressively break them into smaller compounds.

For the new study, researchers from the University of Technology and Applied Sciences and Sultan Qaboos University in Oman collaborated with scientists at Hokkaido University in Japan and the University of South Africa. The team synthesized three forms of graphitic carbon nitride using melamine, urea and thiourea as starting materials. All three materials were produced under the same thermal conditions, allowing the researchers to compare the influence of the precursor rather than differences in manufacturing temperature or treatment time. Graphitic carbon nitride is a metal-free polymeric semiconductor built primarily from carbon and nitrogen. Its layered structure, chemical stability and ability to respond to light have made it an attractive candidate for environmental photocatalysis, although its performance depends strongly on how it is prepared.

The researchers examined the resulting materials using techniques designed to reveal their crystal structure, surface morphology and optical and electronic behavior. They then tested each catalyst in model water solutions containing acetaminophen, cephalexin and levofloxacin at a concentration of five milligrams per liter. The experiments were performed under a controlled artificial light source, with light-only samples serving as a comparison. This setup allowed the team to determine whether pollutant removal resulted from direct photolysis or from the additional catalytic activity of graphitic carbon nitride. The same experimental framework was used for the three materials, creating a controlled comparison of their degradation performance.

One of the clearest differences appeared in manufacturing yield. The melamine-derived material achieved a yield of 31.14%, while the urea-derived catalyst produced a yield of only 8.62%. Yield is more than an industrial accounting figure: it affects the amount of raw material required, the energy and cost associated with production, and the practicality of scaling a catalyst beyond the laboratory. A process that creates a larger quantity of active material under the same conditions may be easier to adapt for future water-treatment systems. The results therefore identify melamine as advantageous not only because of the performance of the final catalyst, but also because it generated substantially more product during synthesis.

The melamine-based graphitic carbon nitride also delivered the strongest overall photocatalytic performance against the three pharmaceuticals, whereas the thiourea-derived material showed the weakest activity. The researchers linked the difference to several interacting properties rather than to a single structural feature. The melamine-derived catalyst displayed greater structural uniformity and crystallinity, characteristics that can help electrons move through the material with fewer losses. It also showed more effective charge separation, reducing the likelihood that light-generated electrons and holes would rapidly recombine before participating in chemical reactions. In addition, its band gap appeared to provide a suitable balance between light absorption and the energetic force required to generate reactive species.

All three catalysts accelerated pharmaceutical degradation compared with the light-only control, demonstrating that the materials contributed actively to the process. When light reaches graphitic carbon nitride, electrons can be promoted from the valence band to the conduction band, leaving holes behind. If these charges remain separated long enough, they can initiate oxidation and reduction reactions at the catalyst surface. The holes may oxidize water or hydroxide ions, while conduction-band electrons can reduce oxygen dissolved in the solution. The resulting reactive oxygen species can attack aromatic rings, amide groups and other chemical structures found in pharmaceutical molecules. The exact reaction pathways are likely to involve multiple intermediate compounds rather than a single step, making it important to evaluate not only the disappearance of the original contaminant but also what happens to the products formed along the way.

To investigate that broader question, the researchers measured total organic carbon, a general indicator of the amount of carbon-based material remaining in the treated water. The observed decline in total organic carbon suggested that the treatment did more than transform the pharmaceuticals into other organic molecules that might remain biologically active. It contributed to the breakdown of the parent compounds and at least some of their degradation products into simpler substances. The team also examined residual antibacterial activity by exposing Escherichia coli to treated solutions. In samples containing cephalexin and levofloxacin, the zones that inhibited bacterial growth became smaller as treatment continued and were no longer detectable under the study’s test conditions after several hours. However, the researchers emphasized that this result does not prove the water became completely harmless. The assay measured antibacterial activity against one bacterial species and cannot replace a comprehensive toxicity assessment covering multiple organisms and chemical endpoints.

The study’s findings highlight precursor selection as a central design decision in the development of graphitic carbon nitride photocatalysts. Melamine, urea and thiourea supply nitrogen and carbon in different chemical environments, and their decomposition during heating can influence porosity, layer formation, defects, crystallinity and the distribution of electronic states within the final material. These microscopic differences can control how much light the catalyst absorbs, how efficiently charges migrate and how readily reactive species form at its surface. The work also suggests that a catalyst optimized for one pollutant may not automatically be the best choice for another, since molecular structure and reaction pathways influence degradation. For researchers seeking inexpensive and metal-free approaches to pharmaceutical removal, the results provide a practical reminder that synthesis chemistry and environmental performance are tightly connected.

The experiments were conducted in controlled laboratory solutions rather than real wastewater, which contains salts, dissolved organic matter, suspended particles and competing contaminants that can block light or consume reactive species. Before the technology could support large-scale treatment, researchers will need to identify all major degradation products, perform broader ecotoxicity tests, determine whether the catalyst remains stable after repeated use and establish how efficiently it can be recovered from treated water. Performance under natural sunlight will also be important, as artificial laboratory illumination may not reproduce the intensity and spectral composition available outdoors. Even with these limitations, the study offers a compelling path forward: by choosing the right precursor at the manufacturing stage, scientists may be able to produce a more uniform, higher-yielding and more effective photocatalyst for reducing pharmaceutical pollution in water.

Subject of Research: Not applicable

Article Title: Pharmaceuticals Acetaminophen, Cephalexin and Levofloxacin: Elimination and Toxicity Study via Carbon Nitride-Based Photocatalyst

News Publication Date: 25 July 2026

Web References: Sultan Qaboos University Journal for Science — https://squjs.squ.edu.om/squjs

References: DOI: 10.53539/2414-536X.1440

Image Credits: Faisal Almarzuqi, Sultan Qaboos University Journal for Science (2026)

Keywords

Graphitic carbon nitride, photocatalysis, pharmaceutical pollutants, water treatment, acetaminophen, cephalexin, levofloxacin, melamine, urea, thiourea, environmental science, materials science, nanomaterials

The study centers on a pressing issue: the presence of pharmaceutical contaminants in water bodies. Sulfamethoxazole and similar compounds often find their way into aquatic environments through various pathways—including wastewater discharge and agricultural runoff—where they pose risks to wildlife and potentially human health. The persistence of antibiotics in water can lead to the development of antibiotic-resistant bacteria, an emerging global health crisis.

To combat this environmental challenge, the researchers implemented a method utilizing a Fenton-like reaction, which traditionally relies on iron catalysis to generate hydroxyl radicals from hydrogen peroxide. This process is known for its effectiveness in degrading organic pollutants. Zhou and his team innovatively adapted this concept by incorporating ultraviolet light, a well-known catalyst in photochemistry, to enhance the reaction kinetics, resulting in a more potent degradation process.

The study method involved systematically testing various conditions, including sulfur concentration, UV light intensity, and hydrogen peroxide levels, to determine the optimal parameters for maximal degradation efficiency. By carefully analyzing the reaction conditions, the researchers sought to establish a more effective and practical approach for wastewater treatment facilities, particularly those dealing with pharmaceutical contaminants.

A key finding from this research indicates that the combination of UV light and hydrogen peroxide significantly accelerates the degradation of sulfamethoxazole compared to systems that do not utilize UV light. This suggests that not only does the Fenton-like reaction work effectively in degrading this antibiotic, but the introduction of UV light catalyzes the production of reactive species, driving the reaction forward more rapidly.

Moreover, the study investigated the degradation byproducts formed during the reaction process. Understanding these intermediates is crucial, as they can sometimes be more toxic than the original compound. The researchers employed advanced analytical techniques to track the transformation of sulfamethoxazole through various stages, revealing a complex matrix of reactions that contribute to the overall efficacy of the method.

Throughout their experiments, the team meticulously documented the influence of different environmental conditions, such as pH and temperature, on the degradation process. These parameters play a critical role in the efficiency of the Fenton-like reaction, as they can significantly affect the production of hydroxyl radicals, which are essential for breaking down complex organic molecules.

In addition to demonstrating the effectiveness of their approach, the researchers also discussed the scalability of this technology for real-world applications. They emphasized the importance of translating laboratory successes into practical solutions for wastewater treatment facilities. Understanding how to optimize and scale up the Fenton-like reaction could pave the way for more sustainable practices in managing pharmaceutical pollution.

The implications of this research extend beyond the immediate findings. As the world grapples with increasing regulations on water quality and the need for sustainable environmental practices, innovations like the one proposed by Zhou and his colleagues offer promising avenues for remediation. The positive outcomes from their study could lead to more robust frameworks for tackling other emerging contaminants that threaten water safety.

Furthermore, the research community’s interest in advanced oxidation processes such as the one explored in this study has been growing. These methods are increasingly seen as vital tools in addressing not only pharmaceutical pollutants but other persistent organic pollutants that challenge water treatment systems worldwide. As such, the work of Zhou et al. contributes valuable insights into the broader discourse on water pollution and remediation strategies.

In conclusion, the study on the Fenton-like reaction augmented with UV light and hydrogen peroxide showcases an innovative and effective approach to degrade sulfamethoxazole in water. The findings emphasize the critical need for continual advancements in environmental remediation technologies to address the challenges posed by pharmaceutical contaminants. This research not only contributes to the understanding of chemical degradation processes but also serves as a hopeful step toward more sustainable water management practices.

As researchers continue to explore and expand upon these findings, the potential for applying such methods to other pollutants could further revolutionize our approach to environmental health and safety. The ongoing commitment to addressing water quality issues will undoubtedly remain a top priority as society seeks to balance development with ecological preservation.

This dynamic interplay between research and application speaks to the urgency and relevance of environmental science and its critical role in safeguarding public health against the backdrop of a rapidly changing world.

Subject of Research: Degradation of sulfamethoxazole using Fenton-like reaction based on UV/H₂O₂.

Article Title: Study on the effect and mechanism of Fenton-like reaction based on UV/H₂O₂ to degrade sulfamethoxazole in water.

Article References: Zhou, B., Li, G., Pan, Z. et al. Study on the effect and mechanism of Fenton-like reaction based on UV/H₂O₂ to degrade sulfamethoxazole in water. Environ Sci Pollut Res (2026). https://doi.org/10.1007/s11356-026-37390-y.

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s11356-026-37390-y

Keywords: Fenton-like reaction, UV light, hydrogen peroxide, sulfamethoxazole degradation, environmental chemistry, wastewater treatment, pharmaceutical contaminants.

Pharmaceuticals, particularly those associated with mental health treatment like sertraline, represent a burgeoning category of pollutants in water bodies. Their presence poses potential risks to aquatic ecosystems and human health, raising an urgent need for effective removal methods. Existing techniques often struggle with the complete degradation of such compounds, prompting the need for innovative photocatalytic solutions. The research led by Hosseini taps into the synergetic properties of cobalt oxide and graphitic carbon nitride to enhance the photocatalytic activity under visible light.

Photocatalysis, a process where light energy activates a catalyst to accelerate a chemical reaction, harnesses the potential of semiconductor materials to break down complex organic pollutants. The integration of Co₃O₄ with g-C₃N₄ is a strategic innovation that significantly improves light absorption, electron-hole separation, and overall photocatalytic efficiency. This dual-component system is characterized by its ability to leverage the visible light spectrum, which is more abundant and environmentally friendly than ultraviolet irradiation, commonly employed in traditional photocatalysis.

The study meticulously details the synthesis of the Co₃O₄/g-C₃N₄ nanocomposite, emphasizing the importance of preparation methods, such as sol-gel or hydrothermal techniques, to achieve optimal structural and electrochemical properties. These properties are crucial as they dictate the photocatalyst’s performance, influencing its effectiveness in degrading sertraline under visible light. The research identifies the optimal ratios of components that yield the best photocatalytic activity, a valuable finding for future applications in environmental remediation.

One of the critical advantages of using Co₃O₄/g-C₃N₄ lies in its enhanced stability and reusability compared to other photocatalysts. This aspect is vital for practical applications, as it reduces the frequency of catalyst replacement and lowers operational costs. The study demonstrates that the nanocomposite retains its efficiency over multiple cycles of use, making it a scalable solution for real-world water treatment challenges. The implications of this resilience extend beyond mere cost savings; they suggest a more sustainable approach to managing pharmaceutical contaminants in water.

Moreover, the experiments conducted in the study reveal the degradation pathway of sertraline when exposed to the Co₃O₄/g-C₃N₄ nanocomposite under visible light. The research employs advanced analytical techniques, including high-performance liquid chromatography (HPLC), to monitor the degradation process and identify the by-products formed. Understanding these pathways is crucial, not only for assessing the efficacy of the treatment process but also for ensuring that the degradation products are themselves environmentally benign.

Crucially, the findings highlight the proposed mechanism of photocatalytic degradation, which involves the generation of reactive oxygen species (ROS) such as hydroxyl radicals. These highly reactive entities play a pivotal role in breaking down the complex molecular structure of sertraline, ultimately leading to its mineralization into harmless by-products. By elucidating this mechanism, Hosseini’s research contributes significantly to the broader understanding of photocatalytic processes, offering insights that could inform future innovations in environmental chemistry.

The implementation of visible-light-driven photocatalysis is particularly promising in regions where sunlight is abundant, maximizing the utility of natural light for water purification. This aspect not only enhances the practicality of the Co₃O₄/g-C₃N₄ system but also aligns well with global sustainability goals, promoting green chemistry solutions that are less dependent on energy-intensive processes. Hosseini’s work embodies a step toward integrating eco-friendly technologies into mainstream water treatment practices.

As environmental regulations tighten and communities demand cleaner water sources, the urgency for effective remediation technologies will only grow. Hosseini’s research provides a vital contribution to the ongoing discourse surrounding pharmaceutical pollutants and their management. The scalable nature of this photocatalyst suggests that it could be deployed in various settings, from industrial wastewater treatment facilities to small-scale applications in rural communities.

In conclusion, the visible-light-assisted decontamination of sertraline using a Co₃O₄/g-C₃N₄ nanocomposite photocatalyst stands as a promising advancement in the field of environmental science. The innovative approach and thorough investigation outlined in Hosseini’s study not only address a pressing environmental issue but also pave the way for future research into novel materials and techniques for water purification. The implementation of such technologies could revolutionize how we approach the detoxification of our water resources, ensuring safer ecosystems and healthier communities.

This research underscores the importance of interdisciplinary collaboration in tackling environmental challenges. By merging insights from chemistry, materials science, and environmental science, researchers can forge pathways toward innovative solutions that mitigate pollution and uphold public health. The evolution of photocatalytic materials promises an era where contaminants like sertraline can be efficiently and sustainably managed, exemplifying the potential of scientific advancement for the greater good.

In light of these findings, there is a clear imperative for continued exploration into other pharmaceuticals and emerging contaminants. The methodologies established by Hosseini’s team can be adapted and expanded to tackle a range of substances that threaten water quality. This expansive potential reflects the transformative impact of photocatalytic research in our ongoing quest for environmental sustainability and public health safety.

Subject of Research: Water decontamination using photocatalysts

Article Title: Visible-light-assisted decontamination of sertraline in water using a Co₃O₄/g-C₃N₄ nanocomposite photocatalyst

Article References:

Hosseini, M. Visible-light-assisted decontamination of sertraline in water using a Co₃O₄/g-C₃N₄ nanocomposite photocatalyst. Environ Sci Pollut Res (2025). https://doi.org/10.1007/s11356-025-36848-9

Image Credits: AI Generated

DOI: 10.1007/s11356-025-36848-9

Keywords: photocatalysis, water treatment, sertraline, Co₃O₄/g-C₃N₄ nanocomposite, environmental science