Removal Efficiency Of Sulfamethoxazole Research Articles

Enrichment and catalysis effect of 2D/2D g-C3N4/Ti3C2 for promoting organic matter degradation and heavy metal reduction in plasma systems: Unveiling the promotion and redox mechanism.

This work proposes a novel plasma-assisted 2D/2D g-C3N4/Ti3C2 system for treatment of organics-heavy metals composite wastewater. Unlike traditional materials in plasma system, 2D/2D g-C3N4/Ti3C2 not only improved the mass transfer efficiency of plasma by gathering both reactive species and pollutants onto the surface, but also induced photocatalytic reactions. Besides, the higher specific surface area and faster carrier separation rate can enhance the oxidation and reduction activity, and then promoted organic matter degradation and heavy metal reduction. Remarkably, the removal efficiency of sulfamethoxazole (SMX) and Cr(VI) increased by 16.5% and 73.1% respectively when introducing 2D/2D g-C3N4/Ti3C2. Roles of·OH,·H,·O2-, 1O2, e-, and h+ in SMX oxidation and Cr(VI) reduction are clarified. The primary aggregated·OH and 1O2 dominate the degradation of SMX. The influencing factors, synergistic mechanism between plasma and catalyst, and redox mechanism were clarified. This work provides a breakthrough idea for treatment of organics-heavy metals composite wastewater.

Enhanced activity of mixed-culture electroactive biofilms and sulfamethoxazole removal efficiency by adding N-acyl-homoserine lactones in bio-electrochemical system

ABSTRACT The addition of exogenous quorum sensing signaling molecules significantly enhanced the degradation efficiency of antibiotics, such as chloramphenicol in bio-electrochemical systems (BESs). However, the effects and mechanisms by which AHLs addition in BES facilitated the removal of sulfamethoxazole (SMX) remained inadequately explored. This study systematically compared the electrochemical performance and SMX removal efficiency in BES under two conditions: with and without the addition of N-acyl-homoserine lactones (AHLs) signaling molecules. In comparison to the control group, the AHL-treated group exhibited an increase in maximum output voltage from 340 to 489.67 mV, alongside a notable enhancement in SMX removal efficiency over 120 h ranging from 14.65% to 15.76%. Analyses of the live and dead cells and extracellular polymeric substances (EPS) composition revealed that following AHLs addition, both the ratio of live to dead cells and protein content within EPS increased by 12.66% and 74.37%, respectively. Furthermore, microbial community structure analysis indicated that after AHLs supplementation, there was a marked increase in the abundance of electroactive microorganisms as well as antibiotic-degrading and nitrogen-removing bacteria. Notably, Klebsiella – characterised by its electroactivity along with antibiotic degradation and nitrogen removal capabilities – exhibited a relative abundance reaching 56.84% in AHL, reflecting an increase of 28.31% compared to Blank; additionally, electroactive bacteria Dysgonomonas showed a relative abundance rise of 2.49%. Collectively, these findings suggested that enhancements in SMX removal efficiency upon AHLs addition were primarily driven by improvements in electrochemical performance coupled with alterations in microbial community structure.

Magnetic MgFeO@BC Derived from Rice Husk as Peroxymonosulfate Activator for Sulfamethoxazole Degradation: Performance and Reaction Mechanism.

Heterogeneous Mg-Fe oxide/biochar (MgFeO@BC) nanocomposites were synthesized by a co-precipitation method and used as biochar-based catalysts to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. The optimal conditions for SMX degradation were examined as follows: pH 7.0, MgFeO@BC of 0.4 g/L, PMS concentration of 0.6 mM and SMX concentration of 10.0 mg/L at 25 ℃. In the MgFeO@BC/PMS system, the removal efficiency of SMX was 99.0% in water within 40 min under optimal conditions. In the MgFeO@BC/PMS system, the removal efficiencies of tetracycline (TC), cephalexin (CEX), ciprofloxacin (CIP), 4-chloro-3-methyl phenol (CMP) and SMX within 40 min are 95.3%, 98.4%, 98.2%, 97.5% and 99.0%, respectively. The radical quenching experiments and electron spin resonance (ESR) analysis suggested that both non-radical pathway and radical pathway advanced SMX degradation. SMX was oxidized by sulfate radicals (SO4•-), hydroxyl radicals (•OH) and singlet oxygen (1O2), and SO4•- acted as the main active species. MgFeO@BC exhibits a higher current density, and therefore, a higher electron migration rate and redox capacity. Due to the large number of available binding sites on the surface of MgFeO@BC and the low amount of ion leaching during the catalytic reaction, the system has good anti-interference ability and stability. Finally, the intermediates of SMX were detected.

Modulating structure of Ce-UiO-66 by introducing fluorinated terephthalic acid for enhanced removal efficiency of antibiotics: Insights into degradation kinetics and pathways

In this work, the 2-fluoroterephthalic acid with asymmetric structure and high electronegative F species was introduced in the assembly of Ce-UiO-66 catalysts to increase the defect density and enlarge pore structure for enhancement in removal efficiency of sulfamethoxazole. Owing to the strong coordination ability from high electronegative F species of 2-fluoroterephthalic acid with Ce-oxo nodes, the designed CUF exhibited improved interfacial properties (accelerated electron transfer rate, available active sites and enhanced interaction with PMS), which was favorable for the exploration and accessibility of active sites with sulfamethoxazole and PMS to decrease the adsorption barrier and accelerate PMS activation. As a result, the CUF catalysts exhibited higher adsorption capacity (173.4 mg/g) than that of CUH (117.8 mg/g), the enhanced degradation efficiency of sulfamethoxazole with a rate constant higher than 2.3 times CUH, good elimination (>95 %) of methylene blue, tetracycline and ibuprofen. In addition, the CUF/PMS system possessed satisfactory stability in wide solution pH, recycling and real water and good potential application in continuous wastewater treatment based on the designed dynamic catalytic reactor. This work provided deep insight into the design of catalysts with high adsorption performance and degradation efficiency based on the structure–activity relationship.

Effect of substrate concentration on sulfamethoxazole wastewater treatment by osmotic microbial fuel cell: Insight into operational efficiency, dynamic changes of membrane fouling and microbial response.

To solve the problems of antibiotic pollution, water resources and energy shortage, an osmotic microbial fuel cell (OsMFC) was adopted innovatively to treat antibiotic wastewater containing sulfamethoxazole (SMX), and achieved SMX removal, water production and electricity generation. Substrate concentration was a key factor affecting the performances of OsMFC, which was often ignored by researchers. This study explored the effect of substrate concentration on system performances, clarified the dynamic changes of membrane fouling under different substrate concentrations, and further revealed the response of microbial communities. The results showed that the stable removal efficiency of SMX exceeded 98.8 % due to the efficient interception of forward osmosis (FO) membrane. Compared with the 1.0 g/L NaAc system, the SMX degradation efficiency and maximum output voltage in the 2.0 g/L NaAc system were only increased by 3.9 % and 6.3 %, respectively. However, the initial water flux decreased by 30.1 % in the 7th cycle due to more serious FO membrane fouling. In addition, there were significant differences in the dynamic formation process of FO membrane fouling. Higher substrate concentration increased the relative abundance of Desulfobacterota and Geobacter. Functional prediction analysis showed that increasing substrate concentration promoted carbohydrate metabolism pathways and relative abundance of sulfur respiration functional groups, thereby improving COD and SMX removal rates. However, the biosynthesis of other secondary metabolites was significantly improved, resulting in increased contents of EPS and SMP, which aggravated membrane pollution. Overall, the system performed better when the substrate concentration was 1.0 g/L. This study would provide certain guidance for the performance optimization and membrane fouling mitigation of OsMFC, thereby promoting its practical application in antibiotic wastewater treatment.

Insight into the nonradical selective oxidation mechanism for versatile organic pollutants removal by perovskite activated peroxymonosulfate system

The heterogeneous catalysis of peroxymonosulfate (PMS) through nonradical pathway has shown many advantages in environmental remediation. It is necessary to unveil the factors affecting oxidation routes and selectivity toward different organic pollutants. Herein, a series of ABO3-type BiFexCo1-xO3 perovskite catalysts were fabricated via simple hydrothermal process to realize the changeover of catalytic activity and mechanism in PMS activation and pollutants oxidation. The as-prepared BiFe0.5Co0.5O3 (BFCO-3) achieved a 98 % removal efficiency of SMZ with a high kinetic constant (kobs = 0.334 min−1) in 10 min. The superior catalytic performance was ascribed to the introduction of bimetals at B-site, which enhanced electron donating capacity to PMS, confirming by d-band center calculations. Several parameters such as inorganic anions and humic acids affected the SMZ degradation slightly, owing that singlet oxygen was verified to be the primary reactive species in the BFCO-3/PMS system. Moreover, twelve organic pollutants including amoxicillin crystalline (AMX), cephalexin hydrate (CFX), ciprofloxacin (CIP), levofloxacin (LFX), Sulfadiazine (SDZ), sulfamethoxazole (SMZ), 4-acetamidophenol (ACP), benzoic acid (BA), bisphenol A (BPA), carbamazepine (CBZ), metronidazole (MNZ) and naproxen (NPX) were utilized to investigate the selective oxidation mechanism. A linear correlation between lnkobs and their half-wave potential (φ1/2) values (except for BA and MNZ) suggesting the dominant role of nonradical catalysis where phenolic compounds with lower anodic potential tend to lose electrons are more easily degraded. Furthermore, the reactive sites of representative SMZ for electrophilic species attack were precisely identified based on the Fukui index. And the degradation intermediates of SMZ were further determined by LC-MS/MS technology for proposing their degradation pathway and predicting ecotoxicity. This study not only provides an efficient advanced oxidation system for organic pollutants removal but also advances our understanding of the selective oxidation mechanism in nonradical-dominated catalytic process.

Sulfamethoxazole removal and ammonium conversion in microalgae consortium: Physiological responses and microbial community changes

Microalgae (Mychonastes sp.) consortium was investigated for nutrient and antibiotics removal and its responses to varying sulfamethoxazole (SMX) concentrations (0–1000 μg/L) in ammonia-rich wastewater. The results showed that the introduction of SMX (100–1000 μg/L) slightly improved ammonium nitrogen removal efficiency instead of inhibition. Swift SMX degradation was observed across all SMX-treated systems, with the highest SMX removal efficiency (96 %) at an SMX concentration of 100 μg/L. Biodegradation remained the dominant SMX removal mechanism, contributing 78 % of SMX removal at an SMX concentration of 800 μg/L, while adsorption and photolysis played minor roles. Addition of SMX augmented biomass and lipid productivity, but decreased chlorophyll contents in the microalgae consortium. Furthermore, extracellular polymeric substance (EPS) production correlated positively with SMX input concentration, with the microalgae consortium exposed to 800 μg/L SMX displaying the most pronounced stimulation of protein production (51.5 ± 2.0 mg/g DCW) and polysaccharides production (74.8 ± 3.9 mg/g DCW). In response to an increase in SMX concentrations, enzyme activities associated with antioxidant defense, such as superoxide dismutase (SOD), peroxidase (POD) and malondialdehyde (MDA) increased, the catalase (CAT) decreased, indicating an initial defense mechanism. Concurrently, the relative abundance of Mychonastes sp. within the consortium rose from 87 % at 300 μg/L SMX to 99.9 % at 800 μg/L SMX. while Shannon indices of the bacterial community increased from 1.415 to 2.867. This shift inhibited the initially dominant Saprospiraceae bacteria, facilitating the profound increase of adapted Aquimonas. These findings demonstrate the feasibility of the simultaneous removal of antibiotics and nutrients from wastewater with a microalgae consortium system.

Anaerobic dynamic membrane bioreactor treating sulfamethoxazole wastewater: advantages of dynamic membrane and its fouling mechanism

Discharge of improperly treated sulfamethoxazole (SMX) wastewater seriously threats environmental security and public health. Anaerobic dynamic membrane bioreactors (AnDMBRs) technology would be cost-effective for SMX wastewater treatment, considering its low cost and satisfactory treatment efficiency. The performance of AnDMBR, though demonstrated to be excellent in treating many types of wastewaters, was for the first time investigated for treating SMX wastewater. Particular efforts were devoted to elucidating the advantages of dynamic membrane (DM) and the governing mechanism responsible for DM fouling with the presence of SMX. The threshold SMX concentration for AnDMBR was found to be 90 mg/L and the AnDMBR exhibited excellent removal efficiency of COD (90.91 %) and SMX (88.95 %) as well as satisfactory acute toxicity reduction rate (88.84 %). It was noteworthy that the DM made indispensable contributions to the removal of COD (14.26 %) and SMX (22.20 %) as well as the acute reduction of toxicity (25.81 %). The presence of SMX significantly accelerated DM fouling mainly by increasing its specific resistance, which was attributed to the increased content of small particles, high-valence metal ions and EPS content (mainly hydrophobic proteins), resulting in a denser DM structure with lower porosity. Besides, the biofouling-related bacteria (Firmicutes) was found to be enriched in the DM with the presence of SMX.

Quantitative and mechanistic elucidation of the reactive oxygen species for effective sulfamethoxazole removal in heterogeneous peroxymonosulfate activated by MOFs-derived cladding structure CoZn/NC@UiO

In cobalt-based catalyst/peroxymonosulfate (PMS) systems, the key issues are the leaching of metals and the stability of catalysts. In this study, a NH2-UiO-66 cladded CoZn/NC catalyst was synthesized for efficient degradation of sulfamethoxazole (SMX) using activated PMS. The removal efficiency of SMX could achieve 100% within 30 min. The leaching of Co2+ was inhibited to 0.05 ppm and the anti-interference and cyclic stability of the catalyst were enhanced by the NH2-UiO-66 shell. In addition, the quenching experiment, electron paramagnetic resonance (EPR) technique and probe experiment were used to analyze the reactive oxygen species (ROSs) qualitatively and quantitatively. The findings demonstrated that singlet oxygen (1O2) had the highest steady-state and cumulative concentration. However, 1O2 could only participate in the degradation of SMX through single electron transfer or addition reaction, resulting in a lower second-order rate constant of the SMX reaction with 1O2. Sulfate radical (SO4·-) contributed the most to the degradation of SMX due to the high reactivity of the sulfonamide structure in SMX to SO4·-. Finally, possible pathways for SMX degradation were proposed. The two primary mechanisms of SMX degradation were S-N cleavage and amino hydroxylation/oxidation. The toxicity of most of the intermediates was less than that of SMX through ecological structure–activity relationship analysis. Overall, a novel approach to synthesize low leaching and efficient cobalt based catalyst was put forward, and the activation mechanism of PMS was also revealed.

Synergistic performance and mechanisms of plasma and peracetic acid for antibiotic degradation in water

Antibiotic pollution has become one of the most challenging environmental issues in aquatic ecosystems, with adverse effects on human health. It is imperative to develop efficient technologies to degrade antibiotics in water to ensure environmental safety. In this study, a novel, efficient, and environmentally friendly method combining peracetic acid with dielectric barrier discharge (PAA/DBD) was developed to degrade sulfamethoxazole (SMX) in wastewater. The combination of PAA and DBD had significant synergistic effects on SMX decomposition with a synergistic factor of 3.67. The incorporation of PAA into the DBD system obviously reduced energy consumption with a 191 % increase in energy yield. The synergistic effects of PAA/DBD can be attributed to the PAA-activating factors generated by DBD (including O3, ultraviolet (UV), H2O2, and heat) and the enhanced effects of H2O2 and CH3COOH (released by PAA) on DBD. This symbiotic relationship between PAA and DBD enhanced the production of various reactive species (including •OH, 1O2, •O2−, ONOO−, and •CH3). The contributions of these reactive species to SMX removal followed the sequence of •O2− > ONOO− >1O2 > •CH3 > •OH. Increasing the PAA dosage and/or DBD discharge power enhanced the efficiencies of the reactive species. Commonly existing anions and cations in wastewater influence the SMX removal efficiency in various ways. Based on the 12 detected intermediates, probable degradation pathways for SMX were proposed. The ecotoxicity assessments of SMX and its intermediates indicated that PAA/DBD treatment minimized the negative effects of SMX on the environment. These observations demonstrated the versatility of PAA/DBD in providing a green, efficient, and innovative approach for removing antibiotics from the water environment.

Atomically dispersed Co atoms anchored on sulfur vacancies to accelerate the electron transfer process and efficiently degrade sulfamethoxazole

Molybdenum disulfide serves as an ideal support for single atom catalysts (SACs), offering not only coordination elements but also abundant active sites, such as surface defects and vacancies. Herein, a novel Co-SAC (MoSO-Co-C) containing a four-coordinated configuration (Mo-Co-C3) is designed and synthesized, in which the carbon intercalation is utilized to regulate sulfur vacancies for anchoring the Co atom. The introduction of Co atoms and C intercalation significantly enhances the Eads between catalyst and peroxymonosulfate (PMS), favoring the formation of metastable intermediates. The kobs of sulfamethoxazole (SMX) removal for MoSO-Co-C is 9.2 times and 1.8 times higher than those of catalysts without Co or C intercalation. SMX is removed mainly by electron transfer pathway, wherein SMX and PMS act on the same Co site of MoSO-Co-C, and electrons are transferred from SMX to MoSO-Co-C and eventually to PMS. The MoSO-Co-C demonstrated excellent SMX degradation in the diverse water matrices, and the removal efficiency of SMX maintained above 95 % after 72 h of continuous degradation. This study provides new insights into the design of transition metal-based SAC and in-depth understanding of PMS activation mechanism.

Unraveling degradation mechanism and reaction efficacy of sulfamethoxazole via reactive oxygen species dominated radical process

Herein, the Ti4O7 electrode was combined for the first time with various oxidants to generate reactive oxygen species for the removal of different organic pollutants in an electrochemical oxidation (EO) system. The removal efficiency of organic pollutants, reaction mechanism, and degradation pathway were evaluated by electrochemical tests, reaction kinetics, electron paramagnetic resonance, quantum chemical, and density functional theory calculations. As a result, nearly 100 % removal efficiency of sulfamethoxazole (SMX) was achieved within 12 min with a high kinetic rate constant of 0.259 min−1, and the kinetic rate constant was strongly dependent on the electrostatic potential. The O2 site on the peroxymonosulfate (PMS) molecule dominated the radical generation for the removal of SMX via the radical and non−radical process. This current study offers a novel approach toward the electrochemical activation of PMS in the elimination and degradation of various organic pollutant from wastewater.

Charge carrier controlled free radical construction efficient photocatalytic self-Fenton system

The photocatalytic self-Fenton technology has demonstrated unique advantages in the low-cost and efficient removal of environmental pollutants. Designing an efficient photocatalytic self-Fenton system (PSFs) to enhance the synergistic effect between photocatalytic H2O2 production and pollutant mineralization processes, as well as understanding the regulatory mechanism of free radical reactions in this process, are crucial for advancing this technology. In this study, an efficient PSFs was developed by coating COFs (TpPa-1) onto the surface of MXene (Ti3C2). Under visible light irradiation, the generation rate of H2O2 reached 983.9 μmol·g−1·h−1, which is 9 times that of pure TpPa-1. Additionally, this led to a significant increase in the removal rate of sulfamethoxazole (SMX) from 25 % to 92 % within 100 min. Photoelectrochemical tests and density functional theory (DFT) calculations confirmed that the incorporation of Ti3C2 not only facilitates efficient charge carrier transport but also enhances the generation of hydroxyl radicals (·OH) and the production of H2O2, thereby improving the photocatalytic self-Fenton removal efficiency of SMX. This research is expected to have a positive impact on the development of efficient PSFs.

Insights to the cooperation of double-working potential electroactive biofilm for performance of sulfamethoxazole removal: ARG fate and microorganism communities

Bioelectrochemical systems (BESs) have shown great potential in enhancing sulfamethoxazole (SMX) removal. However, electroactive biofilms (EBs) constructed with single potentials struggle due to limited biocatalytic activity, hindering deep SMX degradation. Here, we constructed a double-working potential BES (BES-D) to investigate its ability to eliminate SMX and reduce the levels of corresponding antibiotic resistance genes (ARGs). The preferable electrochemical activity of EB in BES-D was confirmed by electrochemical characterization, EPS analysis, physical structure, viability of the biofilm, and cytochrome content. BES-D exhibited a notably greater SMX removal efficiency (94.2 %) than did the single-working potential BES (BES-S) and the open-circuit group (OC). Degradation pathway analysis revealed that the cooperative EB could accelerate the in-depth removal of SMX. Moreover, EB interaction in BES-D decreased the relative abundance of ARGs in biofilms compared to that in BES-S, although the absolute number of ARG copies increased in BES-D effluents. Compared to those in BES-S and OC, more complex cross-niche microbial associations in the EB of BES-D were observed by network analysis of the bacterial community and ARG hosts, enhancing the degradation efficiency of SMX. In conclusion, BES-D has significant potential for SMX removal and the enhancement of EB activity. Nonetheless, the risk of ARG dissemination in effluent remains a concern.

Enhanced removal of sulfamethoxazole via adsorption and photodegradation using biochar-modified iodine-doped TiO2 photocatalysts under simulated sunlight

This study aimed to prepare a biochar-modified iodine-doped titanium dioxide composite photocatalyst (B/I-TiO2) via hydrothermal reaction and evaluate its performance in sulfamethoxazole (SMX) degradation under simulated sunlight. Biochar was prepared from four agricultural wastes using hydrothermal and pyrolysis technologies, resulting in 3–30 graphite layers with a d-spacing of 0.35 nm. Hydrothermal activation transformed the disordered structure into a graphite microcrystalline structure, producing biochar with a quasi-three-dimensional graphene structure. Doping with 1–15 wt% of this biochar shifted the characteristic wavelength of B/I-TiO2 to 423–426 nm and increased the specific surface area by 1.25–1.94 times. The 5LB700H2I1T composite photocatalyst found the highest SMX removal efficiency of 40 %, and the 5WB900H2I1T composite photocatalyst found the highest SMX photodegradation efficiency of 30 %, respectively, irradiated with simulated sunlight of 3 hours. The wavelength redshift and degradation performance enhancement primarily resulted from iodine doping and the biochar's excellent crystallinity and high surface area. SMX removal was achieved through adsorption and photodegradation, with hydroxyl radicals and electron holes playing a significant role compared to superoxide radicals.

Resource utilization of chemical excess sludge to produce metal–organic framework with outstanding Fenton-like performance for sulfamethoxazole removal

The safe disposal of excess sludge has emerged as a pressing concern due to its high toxicity, stemming from a diverse array of components such as viruses, heavy metals, and polycyclic aromatic hydrocarbons. Herein, this study explored the feasibility of using extracted Fe from the excess sludge to produce metal–organic frameworks (MOFs). Specifically, MIL-100 and MIL-88A were successfully synthesized by coordinating 1,3,5-benzene tricarboxylic acid and fumaric acid with excess sludge-retained iron under wide reaction conditions. The purity of the resulting MOFs was ascertained through elemental analysis. Moreover, the synthesized MOFs demonstrated outstanding electrocatalytic performance in the degradation of sulfamethoxazole (SMX). Compared to the control group without catalysts, the addition of MIL-100-170-6 (30 mg) led to a remarkable enhancement in SMX removal efficiency, increasing it to 99.9 % from 58.3 %. This enhancement was accompanied by a substantial increase in the corresponding kinetic constant (kobs) values, reaching 0.1137 min−1, representing an 8.1-fold improvement over the blank group. The catalytic mechanism was further evaluated via quenching experiments and electron paramagnetic resonance (EPR) spectroscopy, suggesting that the •OH and O2•− radicals were responsible for SMX degradation. Economic analysis of MOF materials preparation revealed that the use of excess sludge-retained Fe can significantly reduce the cost of MOFs. Thus, it is believed that our work provides a low-cost and sustainable approach for converting excess sludge into functional MOFs, which not merely facilitates the recycling of excess sludge-retained Fe, but also provides functional materials with outstanding performance for the degradation of SMX.

Developing a novel continuous-flow cascade photocatalytic system for effective sulfamethoxazole elimination from hospital wastewater

In this study, we introduce a novel continuous-flow cascade photocatalytic system specifically designed to efficiently remove sulfamethoxazole (SMX) from hospital wastewater, addressing the critical need for sustainable pharmaceutical wastewater treatment. The system utilizes a carbon sponge-based TiO2 photocatalyst synthesized via a hydrothermal process under mild conditions. The system’s design incorporates multiple stages in a cascade configuration, meticulously optimized to enhance photocatalytic efficacy, thereby significantly improving the rate of SMX elimination while minimizing energy consumption. The study encompasses comprehensive characterization of the photocatalyst, including matching its absorption spectrum to the emission spectrum of the light source, as well as fine-tuning key operational parameters such as catalyst quantity, flow rates, and cascade configuration. Real-world application tests confirm the system’s efficiency, achieving approximately 80 % SMX removal efficiency alongside a notable reduction in Chemical Oxygen Demand (COD) levels. Furthermore, the system’s energy efficiency, as reflected by an Electrical Energy per Order (EEO) value of 7.53 kWh/m3, highlights its potential for scalable and sustainable wastewater treatment solutions. This study not only contributes significantly to the field of environmental catalysis but also represents a significant advancement in sustainable environmental management, offering a promising solution to the urgent challenge of pharmaceutical pollution in water sources.

Efficient sulfamethoxazole removal, water recovery and electricity generation were achieved simultaneously by osmotic microbial fuel cell in treating antibiotic wastewater

Microbial fuel cell (MFC) processes are associated with poor effluent quality when treating antibiotic wastewater. This study innovatively applied osmotic microbial fuel cell (OsMFC) technology to treat antibiotic wastewater while achieving the efficient removal of sulfamethoxazole (SMX), producing high-quality water, and generating electricity. During the stable operation of the OsMFC system, the chemical oxygen demand (COD) removal efficiency reached 80.1%, and the SMX removal efficiency reached 99.3% owing to forward osmotic membrane interception and biodegradation. The high-quality water production rate was 25% ± 5%. Interestingly, the addition of SMX improved the electrochemical performance of the system. The maximum power density was 4,642.4 mW/m3, and the internal resistance was only 230.7 Ω. During long-term operation of the system, membrane fouling was slight, and proteins were the main component of the fouling, followed by α-D glucopyranose polysaccharides and β-D glucopyranose polysaccharides. This study provides a new approach for the treatment of antibiotic wastewater and a novel method for the biodegradation of challenging emerging pollutants.

Degradation of Sulfamethoxazole in Secondary Wastewater Based on Persulfate Activated by Citric-Acid-Complexed Ferrous Ion under Sunlight

The narrow pH application range and lower utilization of ferrous ions (Fe(II)) restrict the application of Fe(II)/persulfate (PS) technology. In this paper, simulated sunlight and citric acid (Cit) as a chelator were introduced in an Fe(II)/PS system to overcome the drawbacks and enhance the degradation of typical antibiotic sulfamethoxazole (SMX) in secondary wastewater. The degradation kinetics, mechanism, and influence factors of SMX in a sunlight/Fe(II)/Cit/PS system and a sunlight/Fe(II)/Cit system as a comparable system were investigated. The removal efficiency of SMX can reach 71.15% and 85.25% in the sunlight/Fe(II)/Cit system and sunlight/Fe(II)/Cit/PS system with 0.1 mM Fe(II), 0.6 mM Cit, and 1 mM PS. The increase of Fe(II) concentration in both systems proved that sunlight promoted the regeneration of Fe(II) from the ferric ion chelates. However, the Fe(II) concentration decreased after 30 min in the sunlight/Fe(II)/Cit/PS system because of the decomposition of Cit. Radical quencher experiments indicated that SO4·−, ·OH, and O2·− contributed 2.48%, 88.43%, and 6.91% to the removal of SMX, respectively. Electron paramagnetic resonance spectra also proved the formation of ·OH and O2·−. The degradation of SMX was proposed to proceed via isomerization, cleavage of S–N bond, and hydroxylation. Overall, the sunlight/Fe(II)/Cit/PS process can be used as an advanced treatment technology for antibiotics in municipal wastewater.

Novel insights into ferrate (VI) activation by Mn-modified sludge biochar for sulfamethoxazole degradation: Dominance of hydroxyl group and Mn-O bond in the non-radical pathway

Ferrate (Fe (VI)), as a versatile oxidizer, has been widely employed for water treatment. However, the rapid self-decomposition of Fe (VI) diminishes its practical application efficiency. In this study, a novel Mn-modified sludge biochar (MSBC) was synthesized for the first time to activate Fe (VI) and generate highly reactive Fe (IV)/Fe (V) for the rapid removal of sulfamethoxazole (SMX). The results showed that MSBC (0.10 g/L) effectively activated Fe (VI) (100 μM), and 87.39 % of SMX (10 μM) and 40.26 % of total organic carbon (TOC) were removed within 10 min. Notably, raising the solution pH (e.g., from 6.0 to 11.0) would result in decreasing the reactivity of Fe (VI) and a lower removal efficiency of SMX. The quenching, electron paramagnetic resonance and probe experiments suggested that •O2– and high-valent iron species (Fe (V)/Fe (IV)) were identified as the major contributions to the removal of SMX. The detailed activation sites of MSBC were –OH and Mn-O, as corroborated by density functional theory (DFT) calculation and characterization. These activation sites facilitated activation of Fe (VI) through efficient electron transfer. The Fukui index indicated that the N, S, and O atom of SMX were the primary attacked sites. Subsequently, five potential degradation pathways were proposed, with the cleavage of the S-N bond being the predominant one. The toxicity of these products was examined using ECOSAR program, revealing that main products showed low toxicity or non-toxicity. The Cl-, SO42-, and NO3– had negligible effect on SMX degradation, although excessive concentrations of HCO3– and humic acid (HA) showed slightly inhibition. Additionally, the Fe (VI)/MSBC system also effectively removed 87.34 % of sulfadiazine (SDZ) and 93.91 % of sulfamethoxypyridazine (SMP). Overall, this study offered a practical and cost-effective approach for the activation of Fe (VI) and provided new insights to the degradation mechanism.