Search Results (160)

This study presents the development of a novel Cu–Co–O-codoped graphitic carbon nitride (g-C₃N₄) catalyst for efficient peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX) in aqueous environments. The synthesized Cu–Co–O-g-C₃N₄ catalyst demonstrated exceptional catalytic performance, achieving 90% SMX removal within 10 min—significantly outperforming pristine g-C₃N₄ (14%) and O-doped g-C₃N₄ (22%)—with a reaction rate constant of 0.63 min⁻¹. The superior activity was attributed to the synergistic effects of Cu-Co bimetallic doping and oxygen incorporation, which enhanced the active sites, stabilized metal ions, and minimized leaching. Mechanistic studies revealed a dual-pathway degradation process: (1) a radical pathway dominated by sulfate radicals (SO₄•⁻) and (2) a non-radical pathway driven by singlet oxygen (¹O₂), with the latter identified as the dominant species through quenching experiments. The catalyst exhibited broad pH adaptability and optimal performance at neutral to alkaline conditions. Characterization techniques (XRD, FTIR, XPS) confirmed successful doping and revealed that oxygen incorporation modified the electronic structure of g-C₃N₄, improving charge carrier separation. This work provides a sustainable strategy for antibiotic removal, addressing key challenges in advanced oxidation processes (AOPs), and highlights the potential of multi-heteroatom-doped carbon nitride catalysts for water purification. Full article

Ozonation has been promoted as a successful methodology for recovering effluents from wastewater treatment plants, with special emphasis on wastewater contaminated with pharmaceutical and personal care products (PPCPs). Still, ozonation reactions may generate potentially toxic by-products, jeopardizing human health safety, a critical aspect considering the use of reclaimed water. We aimed at understanding the potential impacts of ozonation on the quality of reclaimed water for human use through cell viability assays with human skin keratinocytes (HaCaT cell line). Under this context, the cytotoxicity of synthetic effluents contaminated with methyl- and propylparaben, paracetamol, sulfamethoxazole, and carbamazepine, both individually and in mixtures, was assessed before and after ozonation. The viability of HaCaT cells decreased after exposure to untreated synthetic effluents, denoting the cytotoxicity of the tested PPCPs singly and more prominently in mixtures (especially in those combining two and three PPCPs). A similar pattern was observed when testing effluents treated with ozonation. Since the parent contaminants were fully removed during ozonation, the observed cytotoxicity relates to degradation by-products and interactive effects among them. This study suggests that ozonation is poorly efficient in reducing cytotoxicity, as required for the safe use of ozone-treated reclaimed water in activities involving direct contact with human skin. Full article

Shallow lakes are highly vulnerable to pollution due to their small water volume. Those that receive effluent from the drainfields of onsite wastewater treatment systems (septic tanks) may contain pharmaceuticals and personal care products (PPCPs) that escaped removal during treatment. This study examined the effects of seasonal rainfall variability on the assemblages and concentrations of fourteen PPCPs in two shallow lakes in West–Central Florida, USA: one surrounded by residents equipped with septic tanks and the other located within a nature preserve. Water samples were collected weekly during an 18-week interval from April to August 2021. Liquid chromatography–mass spectrometry analyses revealed the omnipresence of five PPCPs: theophylline, caffeine, cotinine, DEET, and testosterone, although acetaminophen, ibuprofen, and sulfamethoxazole were also common. Of all the PPCPs detected, theophylline, DEET, and acetaminophen concentrations were higher during the wet season in the septic tank-influenced lake, while caffeine, cotinine, and testosterone concentrations decreased. In the lake located in the nature preserve, theophylline, caffeine, and acetaminophen levels increased in the wet season. In contrast, cotinine, DEET, and testosterone levels decreased. Overall, more compounds were detected during the wet season, with highly hydrophobic PPCPs (fluoxetine, atorvastatin, and octocrylene) only present during this period. Full article

Multidrug-resistant (MDR) Mycoplasma genitalium (M. genitalium) presents a significant risk of treatment failure in many sexually transmitted infections (STIs) and can result in persistent and recurrent urethritis or cervicitis. This case report describes a recurrent M. genitalium urethritis resistant to sulfamethoxazole-trimethoprim (TMP-SMX), doxycycline, and moxifloxacin. The infection was ultimately cured after both the removal of a nidus of infection and through the use of Lefamulin. Lefamulin is a novel agent approved for use in community-acquired bacterial pneumonia and bacterial skin infections that may be useful in difficult sexually transmitted infections. Background/Objectives: Deciding whether or not to treat M. genitalium can be challenging as it can be a colonizer, or present with a symptomatic pathogen, and even if it is causing symptoms, it can be drug-resistant. Our objective here is to highlight important considerations on whether or not to treat and, if so, what options exist. Conclusions: In a world of increasing drug-resistant STIs, this case highlights the challenges of managing MDR M. genitalium and how foreign bodies can allow reoccurrence. Also highlighted in this case, Lefamulin appears to be a viable alternative line of treatment of MDR M. genitalium that defies other first-line antibiotics. Full article

Sulfonamide drugs (SAs) are a class of emerging contaminants widely present in water environments, which has gradually attracted attention from scholars worldwide. Based on the Web of Science core collection database, this study employs bibliometric methods and visualization tools, such as CiteSpace, Bibliometrix, and VOSviewer, to systematically analyze the literature on the treatment of SAs from 2004 to 2024, exploring the research status, hotspots, and development trends in this field. The results indicate that research on SAs in the past 20 years can be categorized into three stages: initial exploration (2004–2008), slow development (2009–2016), and in-depth research (2017–2024), with an overall increasing trend in number of publications. China and the United States have published the most articles on SAs, with 2266 and 592 articles respectively, and the collaborative ties between the two countries are the strongest. The Chinese Academy of Sciences is the most prolific institution, having published 348 articles. Science of the Total Environment is the journal with the highest publication volume. Among the many SAs, sulfamethoxazole has garnered the greatest research interest, and its primary entry route into the water environment is through the discharge of sewage treatment plants. The research focus has gradually shifted from the source analysis of SAs in the environment to seeking efficient methods for removing SAs. Future research should prioritize investigations into antibiotic-resistant bacteria and antibiotic resistance genes associated with SAs. Full article

Nanotechnology has emerged as a highly focused field of research due to the unique properties of nanometric materials, particularly their large specific surface areas and excellent adsorption capabilities. This study investigated the synthesis of materials based on graphene oxide (GO) functionalized with different metal oxides (MnO₂, Fe₃O₄, CuO, NiO), with potential applications in water decontamination. The morphological, structural, and compositional properties of these nanocomposites were extensively characterized using different experimental techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM) for magnetic property evaluation. Preliminary adsorption tests were performed for the removal of pesticides and drugs from aqueous solutions. The synthesized materials demonstrated a higher affinity for selected pesticides compared to drugs. The best removal efficiencies were 98.59% for cymoxanil, 97.93% for triadimefon, 63.33% for sulfamethoxazole, and 99.59% for diclofenac. The results indicate that the functionalization of GO with metal oxides modifies the material’s structure, increasing its potential for environmental applications such as water purification. Full article

The functionalization of nitrogen-doped graphene with β-Cyclodextrin (designated β/N-rGO) was employed to enhance the dispersibility of graphene materials and to establish an adsorption-catalytic oxidation system using peroxymonosulfate (PMS) for the removal of trace antibiotics from water. The experimental results indicated that β-Cyclodextrin was effectively dispersed on the support structure of nitrogen-doped graphene, which enhanced the specific surface area and dispersibility of the material. The adsorption-catalytic oxidation system comprising β/N-rGO and PMS degraded 92.35% of sulfamethoxazole within 12 min and exhibited significant removal efficiency for sulfonamides, quinolones, macrolides, tetracyclines, β-lactams, and chloramphenicol antibiotics across a pH range of 3–12. The reaction time was reduced by over 10% compared to the unmodified material, with a more pronounced improvement in treatment efficiency, particularly under low-pH conditions. The activation energy of β/N-rGO was estimated to be approximately 4.5 kJ/mol, and elevated temperatures accelerated the reaction, with the removal rate remaining above 85% after five regeneration cycles. Quenching experiments and EPR spectra confirmed that the primary pathway for PMS activation by β/N-rGO was a non-radical process dominated by singlet oxygen. These findings broaden the research and application scope of cyclodextrin–graphene interactions and provide a feasible approach for the removal of trace antibiotics from water. Full article

Photochemical degradation is a major removal pathway for pharmaceutical pollutants in water, and dissolved organic matter (DOM) in water is an important factor affecting this process. This study investigates the differential effects of seasonally-varied dissolved organic matter (DOM) from Songhua River and Liao River on the photodegradation of pharmaceutical pollutants, using levofloxacin (LFX), sulfamethoxazole (SMZ), and ibuprofen (IBP) as target compounds. The results demonstrated that summer and autumn DOM inhibited the photodegradation of LFX and SMZ through light screening and dynamic quenching effects, with inhibition rates of 35.1% and 55.5%, respectively, whereas winter DOM enhanced degradation through photo-oxidation mechanisms. DOM from Songhua River and Liao River significantly promoted the photodegradation of IBP. Quenching experiments showed differences in the contributions of photochemically reactive intermediates (PPRIs) to the photodegradation of different target pollutants, with hydroxyl radicals (•OH) dominating LFX photodegradation (48.79% contribution), excited triplet states of DOM (³DOM*) dominating SMZ photodegradation (85.20% contribution), and singlet oxygen (¹O₂) dominating IBP photodegradation (79.89% contribution). The photodegradation pathways were elucidated by measuring the photodegradation by-products of the target pollutants: LFX mainly underwent piperazine ring cleavage and oxidative decarboxylation, SMZ underwent isoxazole ring opening and deamination during photodegradation, and IBP underwent photodecarboxylation and oxidation reactions. Under the influence of the DOM from the Songhua River and Liao River, the generation of multiple photodegradation by-products led to an increasing trend in the acute toxicity of target pollutants to luminescent bacteria. This investigation elucidates the dual regulatory mechanisms of natural aquatic DOM on both photo-induced degradation pathways and toxicity evolution dynamics of pharmaceutical contaminants, which is of great significance for understanding the photochemical transformation behavior and risk assessment of pharmaceutical pollutants in aquatic environments. Full article

The presence of contaminants of emerging concern (CECs) in agricultural and fisheries water has raised significant environmental and health concerns. Vacuum membrane distillation (VMD) has shown promise as an effective method for removing non-volatile contaminants, such as CECs, from water. This study presents a novel application of a bench-scale VMD unit to treat water from Lagoa da Conceição, Florianópolis, Brazil, using microporous membranes (0.22 µm) under the following optimized conditions: 75 °C, a flow rate of 24 L·h⁻¹, and a vacuum pressure of −640 mmHg. The system demonstrated remarkable performance in removing several key antimicrobials, including sulfamethoxazole, ciprofloxacin, azithromycin, and clindamycin (500 μg·L⁻¹), with rejection rates of 99.1%, 98%, 99.9%, and 99%, respectively, and an average flux of 7.08 L·m⁻²·h⁻¹. Additionally, the VMD unit achieved a substantial 99.98% salt rejection. Ecotoxicity tests revealed low toxicity for sulfamethoxazole, ciprofloxacin, and azithromycin but high toxicity for clindamycin, while human risk assessment indicated moderate-to-high risks for ciprofloxacin and clindamycin. The findings highlight the potential of VMD as an effective and sustainable technology for the removal of CECs and biocompounds, enhancing water safety and reducing environmental hazards. This study offers a promising solution for addressing water contamination on a broader scale. Full article

This study presents a comprehensive kinetic analysis of sulfamethoxazole (SMX) degradation by the photo-Fenton process, highlighting its potential for removing emerging micropollutants in water treatment. The degradation of SMX followed pseudo-first-order kinetics, with increasing Fe(II) concentrations significantly accelerating the oxidation rate. A kinetic model was developed to describe SMX removal, aromaticity loss, and color changes during treatment. Although SMX was rapidly eliminated, intermediate aromatic and chromophoric compounds persisted, requiring extended reaction times for complete mineralization. The kinetic modeling of aromaticity and color revealed distinct degradation pathways and rate constants, showing a strong dependence on iron dosage. The formation of nitrate and sulfate was used to monitor nitrogen and sulfur mineralization, respectively. Optimal nitrate formation was achieved at 22 mol SMX: 1 mol Fe(II), beyond which excessive iron promoted radical scavenging and the formation of stable Fe–aminophenol complexes, inhibiting complete nitrogen oxidation and aromatic degradation. Moreover, excessive Fe(II) led to increased water coloration due to complexation with partially oxidized aromatic byproducts. These findings emphasize the need for optimized catalyst dosing to balance degradation efficiency and minimize secondary effects. The proposed kinetic models offer a predictive tool for improving photo-Fenton-based treatments and integrating them with biological processes to enhance micropollutant bioremediation. Full article

This study examines the degradation of sulfamethoxazole (SMX) in water using the photo-Fenton process, focusing on dissolved oxygen (DO) dynamics, organic matter mineralization, and water quality improvement. The results show that SMX degradation follows a rapid kinetic pattern, achieving complete removal within 30 min. However, total organic carbon reduction occurs more gradually, indicating the persistence of organic intermediates before full mineralization into CO₂ and H₂O. DO evolution follows a biphasic trend: an initial decline due to oxidative consumption, followed by an increase due to H₂O₂ decomposition into O₂. Initially, at [H₂O₂]₀ ≥ 3.0 mM, DO sharply increases, while at [Fe(II)]₀ = 5.0 mg/L, DO reaches a minimum of 0.3 mg/L due to higher reactive oxygen species (ROS) production. Water quality parameters such as color, turbidity, and aromaticity were also monitored. Aromaticity significantly decreases within 30 min, confirming SMX ring cleavage. Color and turbidity initially intensify and increase due to intermediate formation but later decrease as mineralization progresses. Optimal conditions (1 mol SMX: 10 mol H₂O₂: 0.05 mol Fe(II)) ensure efficient degradation with minimal oxygen depletion without excessive scavenging effects. These findings confirm that the photo-Fenton process effectively removes SMX while improving water quality, making it a sustainable alternative for pharmaceutical wastewater treatment. Full article

Sulfamethoxazole (SMX) is a widely used antibiotic for bacterial infections and is frequently found in surface waters and wastewater treatment plant effluents, where it is commonly co-administered with trimethoprim. Because of its emerging ecological and health risks, the development of effective elimination strategies is urgently required. In this study, a rapid microwave-assisted technique was employed to synthesize a Pd/g-C₃N₄ photocatalyst for the elimination of SMX in aqueous solution. The structure and optical properties of all samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), and UV–visible diffuse reflectance spectroscopy. The photocatalytic performance of Pd/g-C₃N₄ was systematically evaluated under visible-light irradiation. The results demonstrated that Pd/g-C₃N₄ achieved a 97% removal efficiency, significantly outperforming pure g-C₃N₄, which reached only 57% removal. The degradation rate constant for Pd/g-C₃N₄ was calculated to be 0.0139 min⁻¹, approximately 6.6 times higher than that of bare g-C₃N₄. This enhanced performance is attributed to the incorporation of Pd nanoparticles, which effectively suppressed the recombination of photogenerated electron–hole pairs and promoted charge separation. The influence of key operational parameters, including pH, SMX concentration, and catalyst dose, were systematically examined. Furthermore, the photocatalytic mechanism of the Pd/g-C₃N₄ photocatalyst was explored to elucidate its degradation pathways. Full article

Mitigating antibiotic pollution is essential to combating antibiotic resistance, safeguarding ecosystems, ensuring food and water safety, and preserving the efficacy of antibiotics. Simultaneously, the comprehensive utilization of red mud is a key approach to reducing resource waste and ecological damage. This study investigates the use of iron components from red mud to prepare RM-nZVI/Ni for Fenton-like reactions, aimed at degrading antibiotics in water. By leveraging the inherent iron content in red mud, RM-nZVI/Ni was developed to achieve a dual-purpose environmental strategy: antibiotic degradation and solid waste resource recycling. The results demonstrate that 0.02 g/L of sulfamethoxazole (SMX) can be fully degraded within 15 min using 0.1 g/L of RM-nZVI/Ni and 6 mM of H₂O₂. Hydroxyl radicals (·OH) and Ni were identified as key contributors to SMX removal. Moreover, this system exhibits universality in degrading common antibiotics such as LFX, NFX, CIP, and TC. LC-MS analysis and DFT theoretical calculations indicate that the degradation byproducts are of lower toxicity or are non-toxic. Additionally, cost analysis suggests that RM-nZVI/Ni is a cost-effective and efficient catalyst. This research gives valuable insights into antibiotic degradation using red mud-based catalysts and offers guidance for expanding the high-value applications of red mud. Full article

As the most promising techniques for refractory antibiotic degradation in wastewater management, sulfate radical-based advanced oxidation processes (SR-AOPs) have attracted considerable attention. However, systematic studies on potassium peroxymonosulfate (PMS) activation by MOF-derived metal oxides coated with LDH materials are still lacking. In this work, a series of catalysts consisting of CoCu-MOFs coated with CuAl/LDH were synthesized for PMS activation in the removal of sulfamethoxazole (SMX). As expected, CoCu-MOFs coated with CuAl/LDH catalyst showed high SMX removal and stability in PMS activation. In the CoCu/LDH/PMS reaction, the SMX removal was nearly 100% after 60 min, and the mineralization reached 53.7%. The catalyst showed excellent catalytic stability and low metal leaching concentrations (Co: 0.013 mg/L, Cu: 0.313 mg/L), as detected by ICP. Sulfate radicals and hydroxyl radicals were identified as the dominant reactive species in the CoCu/LDH/PMS system. Moreover, the presence of ¹O₂ in the process revealed the coupling of non-radical and radical processes. The XPS results showed that the layered structure of CoCu/LDH promoted the recycling of metal ions (high and low valence), which facilitated heterogeneous PMS activation. The effects of different reaction conditions and reuse cycles were also determined. The SMX oxidation pathways were proposed based on the intermediates identified by LC/MS. The high activity and stability of CoCu/LDH provide a new mechanistic understanding of PMS activation catalysts and their potential utilization in practical wastewater treatment. Full article

Membrane filtration has been widely used in wastewater treatment; contaminants attached to the membrane surface led to flux loss and service life reduction. In the present study, a photo-electrocatalysis membrane was fabricated with CNTs@TiO₂ deposited on a commercial polyethersulfone (PES) membrane (PES/CNTs@TiO₂). XRD and SEM characterization proved that the CNTs@TiO₂ composites were successfully fabricated using the one-pot hydrothermal method. Additionally, vacuum filtration was used to distribute the as-prepared powder on the PES membrane. In CNTs@TiO₂, TiO₂ particles were deposited on the outer layer of CNTs, which benefits light adsorption and photocatalytic reaction. The hydrophilicity, light absorption ability, and electron transfer rate of the PES/CNTs@TiO₂ membrane were enhanced compared with the pristine PES membranes. Organic compound removal was improved in the photo-electrocatalysis filtration system with the improvement of 32.41% for methyl orange (MO), 26.24% for methyl blue (MB), 7.86% for sulfamethoxazole (SMZ), and 25.19% for florfenicol (FF), respectively. Moreover, the hydrophilicity and removal rate could be restored after pure water cleaning, demonstrating excellent reusability. The quenching experiment showed that ·OH and ·O₂⁻ were the main reactive oxygen species. This work provides a convenient form of photo-electrocatalysis filtration technology using modified commercial membranes, which has great potential for practical application. Full article