Degradation Of Micropollutants Research Articles

Engineering ZnIn2S4 Nanosheets with Zinc Vacancies: Unleashing Enhanced Photocatalytic Degradation of Tetracycline.

Defect engineering is a highly effective strategy for accelerating charge transfer and enhancing the performance of photocatalysts. In this study, ZnIn2S4 nanosheets were designed and prepared with controlled Zn vacancies to optimize the electronic band structure and localized charge density of ZnIn2S4. EPR results confirmed the formation of Zn vacancies. This modification enabled efficient capture of photoexcited charges in defect centers, thereby prolonging the carrier's lifetime. Theoretical calculations demonstrated that these vacancies induced the formation of new defect states and highly efficient surface reaction sites. As anticipated, under visible light irradiation, the photocatalytic tetracycline removal rate of the ZnIn2S4 nanosheets with Zn vacancies reached 82.8% within 60 min, significantly higher than that observed for the pristine ZnIn2S4 sample. These findings offer valuable insights into the deliberate construction of metal-vacancy-containing photocatalytic nanomaterials for the enhanced degradation of micropollutants.

Differentiation of adsorption and degradation in steroid hormone micropollutants removal using electrochemical carbon nanotube membrane

The growing concern over micropollutants in aquatic ecosystems motivates the development of electrochemical membrane reactors (EMRs) as a sustainable water treatment solution. Nevertheless, the intricate interplay among adsorption/desorption, electrochemical reactions, and byproduct formation within EMR complicates the understanding of their mechanisms. Herein, the degradation of micropollutants using an EMR equipped with carbon nanotube membrane are investigated, employing isotope-labeled steroid hormone micropollutant. The integration of high-performance liquid chromatography with a flow scintillator analyzer and liquid scintillation counting techniques allows to differentiate hormone removal by concurrent adsorption and degradation. Pre-adsorption of hormone is found not to limit its subsequent degradation, attributed to the rapid adsorption kinetics and effective mass transfer of EMR. This analytical approach facilitates determining the limiting factors affecting the hormone degradation under variable conditions. Increasing the voltage from 0.6 to 1.2 V causes the degradation dynamics to transition from being controlled by electron transfer rates to an adsorption-rate-limited regime. These findings unravels some underlying mechanisms of EMR, providing valuable insights for designing electrochemical strategies for micropollutant control.

Assessing the discrepant role of anions in the transformation of reactive oxygen species in H2O2 and PDS system: A comparative kinetic analysis

Clarifying reactive oxygen species (ROS) variation in the presence of co-existing anions is significant for understanding the catalytic effect of magnetite (Fe3O4)-induced advanced oxidation processes (AOPs) in natural environment, yet this remains controversial. Herein, we compare the specific impacts of NO3-, SO42-, and Cl- on ROS (•OH, SO4•-, O2•-, and 1O2) exposure concentration in H2O2 and peroxydisulfate (PDS) systems, as well as how these variations affect the catalytic efficiency by developing kinetic model. In both two systems, NO3- demonstrates no discernible effect on ROS, whereas SO42- inhibits the exposure of all ROS and thus micropollutants degradation. Through theoretical calculation, it is proposed that SO42- primarily exerts its influence through affecting the electronic structure over catalyst surface. Regarding Cl-, it affects ROS exposure mainly by reacting with ROS. It shows inhibitory effect on 1O2 in both systems, but its suppressive impact on •OH is markedly more pronounced in H2O2 system compared to PDS system, which may be related to its rapid reactivity with SO4•-. Besides, the chlorine radicals (mainly ClO•) generated through the reaction of Cl- may exert a selective influence on micropollutants degradation. This study can help to re-understand the influence behavior of co-existing anions during AOPs.

A novel approach for immobilizing Ag/ZnO nanorods on a glass substrate: Application in solar light-driven degradation of micropollutants in water

One of the main challenges in applying photocatalysts for water treatment is the complex separation and recycling process. In this study, we developed highly stable, porous zinc oxide nanorods (ZnO NRs) immobilized on glass vials using a solvent exchange process (SEP) and hydrothermal calcination. Key parameters, including oleic acid concentration and hydrothermal growth time, were optimized to maximize the active surface area, significantly enhancing photodegradation performance. Under the best conditions, ZnO NRs-coated vials achieved nearly 100% degradation of sulfamethoxazole (SMX) in 10 h of simulated solar irradiation. Depositing silver nanoparticles on the surface of ZnO NRs (Ag/ZnO NRs) further improved performance, reducing degradation time to 4 h and increasing photocatalyst stability. The Ag/ZnO NRs-coated vials, optimized with an Ag precursor concentration of 0.05 M, also demonstrated high degradation rates (>99%) for eight organic micropollutants at environmentally relevant concentrations over multiple reuse cycles and with minimal metal leaching. This study presents an innovative, tunable method for immobilizing photocatalysts on glass substrates, offering high surface area, excellent photocatalytic activity, and mechanical properties, making it highly suitable for water treatment applications.

Influence of S(IV) reduction on the reaction mechanisms and the generation of reactive oxygen species in B-Cu@Fe/PPS system

Heterogeneous sulfite-based advanced oxidation process is extremely promising for the removal of various industrial pollutants owing to its generation of multiple reactive oxygen species (ROS), while the unclear mechanism of S(IV) conversion and ROS generation hinder its practical applications. Here, the iron-copper bimetallic was synthesized for potassium pyrosulfate catalysis, which was designed for insight into the mechanism of micropollutant degradation driven by sulfur species conversion. Experimental and theoretical calculations have shown that the reaction process and corresponding mechanisms can be significantly distinguished into three different stages. Stage one prepares sufficient Fe(III) for the initiation of the reaction, while stage two generating ROS and reduces S(IV). In the stage three, the low-valent sulfur produced from S(IV) combines with iron-copper materials to form highly active sulfur sites, which react with O2 to generate a large number of hydroxyl radicals (•OH). Furthermore, a variety of contaminants were used to validate the universality of the system, and their wide distribution in wastewater implies broad application prospects. This research provides in-depth interpretations of the induced mechanism of sulfur species conversion in the sulfite heterogeneous system, provides a solid theoretical foundation for the engineering application of the system.

Unique role of doped Mo into Fe-based catalyst to intensify peroxydisulfate activation for micropollutants degradation: Promote the conversion of SO4•- to FeIV = O

Herein, Fe/Mo-based composite catalyst (FeMo@CN) was synthesized to catalyze peroxydisulfate (PDS) for efficient bisphenol A (BPA) degradation. Within 1 h, the FeMo@CN/PDS system could degrade BPA fully (kobs = 0.12 min−1, which was 129 times higher than system without Mo introduction). Probe experiments and 57Fe Mossbauer indicated that BPA degradation was dominated by SO4•- and FeIV = O converted from SO4•- (Fe(II)-PDS → Fe(III)-SO4•-→FeIV = O-HSO4-). This finding broke down the boundary between radical and non-radical, proposing a new path from SO4•- to FeIV = O. As Density functional theory (DFT) calculations revealed, Mo in FeMo@CN promoted PDS adsorption and reduced generation energy barrier of SO4•- and FeIV = O, achieving a dual improvement. Besides, the stable and efficient BPA degradation in dynamic degradation experiment demonstrated the application potential of FeMo@CN. This work provides a novel method to solve blocked Fe(II)/Fe(III) cycle and re-reveals FeIV = O generation mechanism in SR-AOPs.

Recent innovations in engineering Zinc Oxide (ZnO) nanostructures for water and wastewater treatment: Pushing the boundaries of multifunctional photocatalytic and advanced biotechnological applications

Owing to its rapid advancement in nanotechnology, latest publications (recent 5 years) related to zinc oxide (ZnO) in various aspects and applications have been reviewed. Trend has shifted to the innovation of pristine ZnO nanostructures functionalized with elemental dopants and heterojunction to improve the photoactivities on micropollutant degradation and heavy metals removal as well as the antibacterial effect towards microorganisms. The fundamentals of improved photoactivities (i.e., low recombination rate of charge carrier and effective charge transfer) and enhanced antibacterial properties (i.e., dissolution of ions and generation of reactive oxygen species) are accentuated. Subsequently, a detailed examination is undertaken to elucidate the key impacts of ZnO on actual wastewater treatment systems. This review concludes with a consolidated overview on the recent advances of ZnO for environmental wastewater decontamination and the future prospects on tailoring ZnO based on their photocatalytic and antibacterial properties to match various expectations from practical applications while minimising the adverse impacts on surrounding environment.

Sustainable Wastewater Treatment Strategies in Effective Abatement of Emerging Pollutants

The fundamental existence of any living organism necessitates the availability of pure and safe water. The ever-increasing population has led to extensive industrialization and urbanization, which have subsequently escalated micropollutants and water contamination. The environmental impact on various life forms poses a dire need for research in effective environmental management. Versatile technologies involving multiple approaches, including physiochemical and biological bioremediation strategies, draw insights from environmental biology. Metabolic annihilation mediated by microbes shows significant potential in the bioconversion of toxic micropollutants to tolerable limits. Environmentally friendly, cost-effective, and sustainable strategies are envisaged for efficient environmental protection. Phytoremediation technology, especially floating wetland treatments, facilitates micropollutant elimination, landscape management, ecosystem conservation, and aesthetic enhancement in diverse environments. The incorporation of nanomaterials in the bioremediation of toxic micropollutants augments novel and innovative strategies for water pollution abatement. This paper offers a novel strategy that combines nanomaterials to improve micropollutant degradation with bioremediation techniques, particularly the creative application of phytoremediation technologies like floating wetlands. Combining these techniques offers a novel viewpoint on long-term, affordable approaches to reducing water pollution. Additionally, the review proposes a forward-looking strategic framework that addresses the accumulation and refractory nature of micropollutants, which has not been thoroughly explored in previous literature.

Reactive Oxygen Species Generated in Situ During Carbamazepine Photodegradation at 222 nm Far-UVC: Unexpected Role of H2O Molecules.

When 222 nm far-UVC is used to drive AOPs, photolysis emerges as a critical pathway for the degradation of numerous organic micropollutants (OMPs). However, the photodegradation mechanisms of the asymmetrically polarized OMPs at 222 nm remain unclear, potentially posing a knowledge barrier to the applications of far-UVC. This study selected carbamazepine (CBZ), a prevalent aquatic antiepileptic drug that degrades negligibly at 254 nm, to investigate its photodegradation mechanisms at 222 nm. Accelerated CBZ treatment by 222 nm far-UVC was mainly attributed to in situ ROS generation via self-sensitized photodegradation of CBZ. By quenching experiments and EPR tests, •OH radicals were identified as the major contributor to the CBZ photodegradation, whereas O2•- played a minor role. By deoxygenation and solvent exchange experiments, the H2O molecules were demonstrated to play a crucial role in deactivating the excited singlet state of CBZ (1CBZ*) at 222 nm: generating •OH radicals via electron transfer interactions with 1CBZ*. In addition, 1CBZ* could also undergo a photoionization process. The transformation products and pathways of CBZ at 222 nm were proposed, and the toxicities of CBZ's products were predicted. These findings provide valuable insights into OMPs' photolysis with 222 nm far-UVC, revealing more mechanistic details for far-UVC-driven systems.

CoFe2O4/carbon nitride Z-scheme heterojunction photocatalytic PMS activation for efficient tetracycline degradation: Accelerated electron transfer

The escalating consumption of antibiotics and their subsequent discharge into the water supply is a matter of significant concern. This study presents an innovative visible light (VL) activated peroxymonosulfate (PMS) system for efficient degradation of the targeted antibiotic tetracycline (TC). CoFe2O4/carbon nitride (CFO/CN) Z-scheme heterojunctions were designed and synthesized through a simple co-precipitation and calcination strategy. Surface and analytical techniques were employed to comprehensively characterize the prepared CFO/CN, demonstrating its enhanced efficiency in separating photoinduced charge carriers. CFO/CN exhibited a 27-fold enhancement in TC degradation rate constants with PMS under VL. The effects of various factors including catalyst dosage, PMS concentration, initial pH, and content of CFO on TC degradation efficiency were investigated. Reactive species quenching and EPR measurements revealed the main contribution of superoxide radicals (•O2−) made to TC degradation. TC degradation pathways were proposed based on oxidized product analysis. The assessment of acute toxicity demonstrated the reduced toxicity of the formed intermediates. A plausible mechanism for TC degradation over CFO/CN-PMS-VL was discussed. This work provides a comprehensive guide for heterojunction photocatalytic activation of PMS for efficient micropollutant degradation.

The reverse-reduction effect of dissolved organic matter on the degradation of micropollutants induced by halogen radicals (Cl2•- and Br2•-)

Reactive halogen radicals (e.g., Cl2•- and Br2•-) greatly impact the degradation of micropollutants in natural waters and engineered water treatment systems. The ubiquitous dissolved organic matter (DOM) in real waters is known to greatly inhibit the degradation of micropollutants by reducing micropollutant's intermediate (i.e., TC•+/TC(-H)•), however, such DOM's effects on the halogen-radical-induced system have not been understood yet. The present study focuses on investigating and quantifying such inhibitory effects of DOM during Cl2•-- and Br2•--mediated process. Guanosine (Gs) was selected as a model compound. The transient spectra show that Cl2•- and Br2•- react with Gs generating intermediates (i.e., Gs•+/Gs(-H)•) via single-electron transfer. In the presence of 1.0 mgCL-1 DOM, over 70% of this oxidized Gs was reduced back to Gs. Comparing the extent of reverse-reduction inhibitory among different reaction systems, this inhibitory in Br2•- system was slightly lower than that in Cl2•- and SO4•- system, corresponding the slightly difference of inhibition factor (IF) values as SO4•- < Cl2•- < Br2•-. The reverse-reduction effect of DOM was further quantified for 19 common micropollutants. It varied significantly with IF values of 0.21–1.26 and 0.28–1.40 in Cl2•-- and Br2•--mediated process, respectively. Purines and amines generally exhibited more pronounced inhibition than phenols in both systems. A good correlation of IF values with micropollutant's reduction potential was observed, which can be applied to predict the degradation of more unstudied micropollutants. This study highlights the important role of the reverse-reduction effect of DOM on micropollutant degradation. It can significantly improve the accuracy in predicting degradation rate in advanced oxidation processes for treating water containing halides.

Iron–molybdenum bimetals incorporated montmorillonite-based catalytic ceramic membrane for heterogenous Fenton reaction towards the degradation of micropollutants in water

This study developed an innovative material approach that integrated Fenton catalysis with membrane filtration in a single system using iron–molybdenum bimetal oxides (FeMoO) incorporated montmorillonite (MMT)-based ceramic membrane (FeMoMMTCM) to achieve continuous Fenton reaction for water purification. The embedded bimetallic FeMoO catalyst created abundant active Fe(II) sites on the external and internal surfaces of the ceramic membrane (CM) for H2O2 activation. Using naproxen (NPX) as a model micropollutant in water, the FeMoMMTCM/H2O2 system achieved a 98.6 % removal of NPX (10 mg/L) within a filtration period of 3.4 min through the membrane, in comparison to a 17.5 % removal by FeMoMMTCM filtration with no H2O2 dosing and a 21.1 % removal by the FeMoO-less MMTCM/H2O2 system. The catalytic membrane demonstrated its high NPX removal efficiency over multiple cycles, retaining its effectiveness even in the presence of co-existing ions and organic matter in the water matrix. Furthermore, the FeMoMMTCM/H2O2 system was able to remove nearly 70 % of residual organic pollutants from the actual secondary wastewater effluent. The quenching tests and electro-paramagnetic resonance (EPR) detection confirmed the generation of hydroxyl (OH) and superoxide (O2−) radicals from H2O2. The excellent catalytic performance can be attributed to the Fe-Mo bimetallic catalyst, in which the active Mo(VI)/Mo(IV) cycle can facilitate the Fe(II)/Fe(III) cycle for continuous Fenton reaction. The cost analysis indicates that the low-cost MMT and its low sintering temperature for ceramics would greatly decrease the cost of MMTCM (243.1 US$/m2 vs. 541.5 US$/m2 of alumina-based CM). Overall, the research presents a technical strategy for the fabrication of highly cost-effective catalytic membranes with Fenton reaction for removing micropollutants from water.

Simulated sunlight-driven photocatalytic activation of peroxydisulfate by core–shell Ag@SiO2/TiO2 nanocomposite for efficient methyl orange degradation

Herein, core–shell Ag@SiO2/TiO2 nanocomposites were synthesized and applied to activate peroxydisulfate (PDS) for wastewater purification. The Ag core and Ag-doped TiO2 shell were obtained by stober method and calcination method. The dispersion degree and size of Ag in TiO2 would influence the oxygen vacancy. Ag enhanced the visible absorption of TiO2 and activated PDS. Improved degradation performance was attributed to enhanced PDS activation by photogenerated e−, which separated h+and thus promoted methyl orange(MO) degradation. Reactive oxidative species were verified under dark and light conditions via quenching experiments and electron paramagnetic resonance tests, demonstrating SO4•–, h+, O2•–, and1O2were formed in light,whereasSO4•–, •OH, O2•–, and 1O2were responsible for MO degradation under dark conditions. The Ag@SiO2/TiO2/PDS/light system showed selectivity for removal of cationic dyes (e.g., methylene blue and malachite green) through adsorption and photocatalysis, whereas anionic dyes (e.g., MO) were degraded by photocatalysis alone. Besides, we found excess adsorption of micropollutant onto catalyst may be adverse to the activation of PDS. Therefore, the adsorption of oxidant (such as PDS) onto the catalyst surface would be beneficial for catalytic activation and micropollutant degradation, especially onto active sites. This work aims to provide a new avenue for core-shell structure catalyst synthesis in wastewater purification.

Enhanced degradation of micropollutants using In situ electrogenerated sulfate radical at high flux

The degradation of micropollutants via in situ-generated reactive species from coexisting substances in water is a promising approach for advanced water treatment. However, treatment efficiency and practical applications are hindered by limited operation conditions and prohibitive costs, respectively. Herein, we report an upgraded electrochemical filtration system that is chemical-free and made efficient by achieving in situ SO4•– generation at enhanced flux and in complicated water matrices. The ion transport was enhanced by coupled electric and flow fields, providing an outstanding performance in removing micropollutants. At the optimized conditions, the proposed system degraded 90.5% of bisphenol A (BPA) in 40 min and its degradation kinetics was 14.7 times that of the batch mode, and the treatment efficiency of the proposed system was 2.5 times more efficient than our previous design because of the enhanced flux. Quenching experiments indicate that indirect oxidation by SO4•– and •OH as well as direct electron transfer play critical roles during the BPA degradation. Importantly, the proposed system does not need any added chemicals and uses only the ubiquitous SO42− and electricity. From an environmental point of view, its energy conservation and the lack of additional chemicals ensure its applicability for purifying micropollutants.

Rapid Peracetic acid activation by CoO under neutral condition: The contribution of multiple reactive species

This paper proposes a novel process of cobalt monoxide (CoO)-activated peracetic acid (PAA) for treating emerging micropollutant in water. PAA was activated under neutral conditions by combining a dominant heterogeneous phase on the catalyst surface and a homogeneous phase by dissolved Co2+. The system produced several reactive oxygen species, including hydroxyl radicals (HO∙HO•), singlet oxygen (1O2), organic radicals (RO•(CH3C(O)O•, CH3C(O)OO•) and high-valent cobalt (Co(IV)). Organic radicals and high-valent cobalt primarily drove the emerging micropollutants degradation, interacting via electron transfer. Further density functional theory calculations supported that the spontaneous adsorption of PAA onto the catalyst could break peroxy bonds that generate radicals. Furthermore, the CoO surface structure underwent minimal changes during the reaction, making it highly reusable. Thus, the novel CoO/PAA system could be an effective advanced oxidation process for water treatment.

Assessing excimer far-UVC (222 nm) irradiation for advanced oxidation processes: Oxidants photochemistry and micropollutants degradation

The KrCl* excimer lamp (UV222) is a promising alternative of low-pressure mercury lamp (UV254) for UV-based advanced oxidation processes (UV-AOPs), because it is mercury-free and has high photon energy. But there lacks a comprehensive assessment of UV222-AOPs based on different radicals. Herein, the properties (e.g., oxidant decay and innate radical quantum yield), and micropollutant degradation, were comprehensively studied for representative oxidants (i.e., hydrogen peroxide, persulfate (PDS), monochloramine, and free active chlorine (FAC)) under UV222 irradiation. UV222 outperformed UV254 for the activation of oxidants with 2.6–14.4 times fluence-based kinetic constant (kF). The main reason of enhanced activation varied with oxidants: higher UV absorbance for H2O2, higher innate quantum yield for monochloramine and FAC, and both reasons for PDS. Overall, PDS was the optimum oxidant under UV222 for the degradation of 8 representative micropollutants because of effective promotion of radical formation, as confirmed by radical competitive kinetics and modeling simulations. In real water, UV222/PDS still show advantages than UV254/PDS in terms of micropollutant elimination efficacy (3.2–5.3 times) and energy consumption (33.9 %-57.6 % lower) though it was more inhibited by water constituents via competing for UV222 photons. This study fills gaps in photochemistry knowledge and will facilitate engineering practice of UV222-AOPs.

A new perspective on contaminants as "activators": Aromatic amine groups promoted degradation of tetracycline by ferrate(VI)

Occasionally, our group found that the degradation of tetracycline by ferrate(VI) could be promoted by four co-exist contaminants, containing aromatic amines (ofloxacin, diatrizoic acid, sulfadiazine and alachlor). This study investigated the promotion of aromatic amine groups on tetracycline degradation by ferrate(VI) by using aniline as a model compound. The results implied that the presence of aniline increased the degradation rate of tetracycline by 2.76 times, and the enhancement was weakened gradually with the decrease of pH from 10 to 7.5. The generation of Fe(IV) and·OH by the reaction between ferrate(VI) and aniline was proposed to enhance the degradation of tetracycline, supported by quenching experiments, electron paramagnetic resonance (EPR) and theoretical calculations. A positive correlation was found between the rate constant of tetracycline degradation and the electron-donating ability of the substituted amines (quantified by the Hammett substituent constants). In addition, the degradation of tetracycline was remarkably inhibited by HA and some inorganic ions such as NO3-, SO42-, Cl-, Ca2+, and Mg2+, and the inhibition also happened in the Songhua River water and the secondary effluent. The present study provided an insight into the complex oxidation process for the degradation of micropollutants containing aromatic amine by ferrate in water treatment.

Activation of periodate by C2N3 loaded with metal single-atoms for ultrafast removal of micropollutants: Electron transfer outperforms reactive oxygen species

Different transition metal single-atoms may lead to a variety of reaction mechanisms in advanced oxidation processes (AOPs). The transition metal (Fe, Ni and Mn) single-atom C2N3 catalysts were used to degrade acetaminophen (AP) by activating periodate (PI). Mn-CN+PI system can completely remove AP in 2 min, and its rate constant (5.7550 min−1) was 9.37 and 22.69 times higher than that of Ni-CN+PI and Fe-CN+PI. The system showed excellent performance in different influencing factors and micropollutant removal experiments. The recyclable Mn-CN sponge sheet showed good practical application performance in microreactor experiments. Electron paramagnetic resonance, radical quenching, electrochemical experiments, combined with theoretical simulation certified that Mn-CN+PI system was dominated by electron transfer mechanism, which was superior to reactive oxygen species that dominated Ni-CN+PI and Fe-CN+PI systems. The electron transfer-mediated pollutant degradation provides insights into PI-based AOPs, and offers a feasible pathway for micropollutant degradation.

Theoretical evidence for a pH-dependent effect of carbonate on the degradation of sulfonamide antibiotics

Carbonate (CO32−/HCO3−) have a significant impact on advanced oxidation processes (AOPs) by consuming reactive free radicals such as HO• to generate CO3•-. However, research on the mechanisms and kinetics of CO3•- remains limited. This study investigates the degradation mechanism and kinetics of sulfonamide antibiotics (SAs) by CO3•- through theoretical calculations. The calculation results revealed that the effect of CO3•- on SAs degradation is pH-dependent due to the dissociable sulfonamide group (-SO2NH-) of SAs in the common water treatment pH range (3–8). The main reaction type of CO3•- with both neutral and anionic molecules of SAs is single electron transfer reaction. Frontier molecular orbital theory (FMO) illustrated that deprotonation of the sulfonamide group of SAs decreases the charge density on the heterocyclic ring, facilitating the electrophilic addition of CO3•-. The second-order rate constants of the neutral and anionic molecules of SAs with CO3•- were calculated as 7.57 × 101∼1.84 × 108 and 1.81 × 107∼7.94 × 109 M−1 s−1, respectively, resulting in an increase in the apparent reaction rate constants with pH. Stepwise multiple linear regression was employed to predict reactivity with anionic sulfonamide antibiotics (SAs−). Two models with outstanding prediction and stability were developed with coefficients of determination R2 of 0.660 and 0.681, respectively. The degradation kinetics simulation indicated that in the UV/H2O2 process in the presence of carbonate, the degradation rate of SAs increased with pH. Furthermore, the contribution of CO3•- to SMX degradation increased while that of HO• decreased. This study highlights the contribution of carbonates to the micropollutant degradation in the UV/H2O2 process as the model, providing theoretical insights into the development of carbonate-based AOPs.

Recent advances and future trends in metal oxide photocatalysts for removal of pharmaceutical pollutants from wastewater: a comprehensive review.

The rapid and widespread increase in pharmaceutical micropollutants (PMPs) poses a significant and immediate threat to ecosystems and human health globally. With the demand for clean water becoming increasingly critical, particularly amid escalating global water scarcity challenges, there is an urgent need for innovative approaches. Among the potential solutions, metal oxide photocatalysts such as titanium dioxide-based (TiB) and zinc oxide-based (ZnB) have garnered attention due to their cost-effectiveness, efficient photodegradation capabilities, and inherent stability. This comprehensive review explores recent advancements in the application of TiB and ZnB for the removal of PMPs from wastewater. It examines the multifaceted impacts of PMPs on environmental and public health, evaluates various techniques for their removal, and assesses design strategies aimed at maximizing the photocatalytic efficiency of TiB and ZnB. The mechanisms responsible for the photocatalytic degradation of pharmaceutical micropollutants using TiB and ZnB photocatalysts are comprehensively detailed. Finally, the review outlines the prospects and challenges associated with the use of TiB and ZnB photocatalysts for the removal of PMPs from wastewater. It emphasizes their potential to effectively mitigate PMP contaminants and make substantial contributions to sustainable water management practices in the face of escalating environmental and public health concerns.