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In recent years, the environmental impact of pharmaceutical residues has emerged as a pressing global concern, catalyzed by their widespread usage and persistence in aquatic ecosystems. Among these pharmaceuticals, acyclovir (ACV) stands out due to its extensive prescription during medical treatments for herpes simplex virus, chickenpox, and shingles, as well as its heightened usage amidst the COVID-19 pandemic. ACV is excreted largely unchanged by the human body, leading to significant environmental release through wastewater effluents. The urgency of addressing ACV's environmental impact lies in its potential to persist in water bodies and affect aquatic life. This persistence underscores the critical need for effective degradation strategies that can mitigate its presence in aquatic systems. This study focuses on employing sodium hypochlorite as an oxidative agent for the degradation of ACV, leveraging its common use in wastewater treatment plants. Our research aims to explore the kinetics of ACV degradation, identify and characterize its degradation byproducts, and optimize the conditions under which complete degradation can be achieved. By assessing the efficiency of sodium hypochlorite in real wastewater samples, this study seeks to provide practical insights into mitigating ACV contamination in aquatic environments. The novelty of this research lies in its comprehensive approach to understanding the degradation pathways of ACV and evaluating the feasibility of using sodium hypochlorite as a sustainable solution in wastewater treatment. By addressing the environmental concerns associated with ACV and offering practical solutions, this study contributes to the broader goal of sustainable pharmaceutical waste management and environmental stewardship. [ABSTRACT FROM AUTHOR]

The preparation of anodic TiO2 nanotube layers has been performed using electrochemical anodization of Ti foil for 4 h at different voltages (from 0 V to 80 V). In addition, a TiO2 thin layer has been also prepared using the sol–gel method. All the photocatalysts have been characterized by XRD, SEM, and DRS to investigate the crystalline phase composition, the surface morphology, and the optical properties, respectively. The performance of the photocatalyst has been assessed in versatile photocatalytic reactions including the reduction of N2O gas and the oxidation of aqueous sulfamethoxazole. Due to their high specific surface area and excellent charge carriers transport, anodic TiO2 nanotube layers have exhibited the highest N2O conversion rate (up to 10% after 22 h) and the highest degradation extent of sulfamethoxazole (about 65% after 4 h) under UVA light. The degradation mechanism of sulfamethoxazole has been investigated by analyzing its transformation products by LC-MS and the predominant role of hydroxyl radicals has been confirmed. Finally, the efficiency of the anodic TiO2 nanotube layer has been tested in real wastewater reaching up to 45% of sulfamethoxazole degradation after 4 h. [ABSTRACT FROM AUTHOR]

The key role of trivalent manganese (Mn(III)) species in promoting sulfate radical-based advanced oxidation processes (SR-AOPs) has recently attracted increasing attention. This review provides a comprehensive summary of Mn(III) (oxyhydr)oxide-based catalysts used to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) in water. The crystal structures of different Mn(III) (oxyhydr)oxides (such as α-Mn2O3, γ-MnOOH, and Mn3O4) are first introduced. Then the impact of the catalyst structure and composition on the activation mechanisms are discussed, as well as the effects of solution pH and inorganic ions. In the Mn(III) (oxyhydr)oxide activated SR-AOPs systems, the activation mechanisms of PMS and PDS are different. For example, both radical (such as sulfate and hydroxyl radical) and non-radical (singlet oxygen) were generated by Mn(III) (oxyhydr)oxide activated PMS. In comparison, the activation of PDS by α-Mn2O3 and γ-MnOOH preferred to form the singlet oxygen and catalyst surface activated complex to remove the organic pollutants. Finally, research gaps are discussed to suggest future directions in context of applying radical-based advanced oxidation in wastewater treatment processes. [ABSTRACT FROM AUTHOR]

This paper outlines the synthesis and application of a sustainable composite for the photo-Fenton-like degradation of caffeine, bisphenol A, and simazine. The phase, morphology, optical and magnetic properties of the samples were evaluated by different characterization techniques. The composite of Fe 2.5 Co 0.3 Zn 0.2 O 4 and copper-chromium layered double hydroxide (CuCr-LDH) was determined to be the most favorable photocatalyst in the photo-Fenton-like process when compared with Fe 3 O 4 , Fe 2.5 Co 0.3 Zn 0.2 O 4 , CuCr-LDH, and Fe 3 O 4 /CuCr-LDH composite. Studying the efficiency of the photo-Fenton-like degradation process in the presence of the Fe 2.5 Co 0.3 Zn 0.2 O 4 /CuCr-LDH composite revealed a degradation rate constant of caffeine twice more than the sum of those obtained for the individual processes. This ascribes to the synergistic effect by which the photo-generated electron-hole from the catalyst and the efficient reduction of Fe 3+ , Cu 2+ , etc. during the photo-Fenton-like reaction is accelerated. Moreover, under the optimal condition and after 120 min of heterogenous photo-Fenton-like process at natural pH, > 90% of pollutants mixture was decomposed. The experiments fulfilled in near-real conditions demonstrated I) the high stability and magnetically recoverability of the photocatalyst and II) the proper degradation performance of the applied heterogenous photo-Fenton-process in the removal of pollutant mixture in different water bodies and in the presence of chloride and bicarbonate ions., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this paper, the degradation of three endocrine-disrupting chemicals (EDCs): bisphenol A (BPA), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) by manganite (γ-MnOOH) activated peroxymonosulfate (PMS) was investigated. Preliminary optimisation experiments showed that complete degradation of the three EDCs was achieved after 30 min of reaction using 0.1 g L -1 of γ-MnOOH and 2 mM of PMS. The degradation rate constants were determined to be 0.20, 0.22 and 0.15 min -1 for BPA, E2 and EE2, respectively. Combining radical scavenging approaches, Electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) analyses, we revealed for the first time that about 40% of EDCs degradation can be attributed to heterogeneous electron transfer reaction involving freshly generated Mn(IV), and 60% to sulfate radical degradation pathway. The influence of various inorganic ions on the γ-MnOOH/PMS system indicated that removal efficiency was slightly affected by chloride and carbonate ions, while nitrate and nitrite ions had negligible impacts. The application of γ-MnOOH/PMS system in real sewage treatment plant water (STPW) showed that degradation rate constants of EDCs decreased to 0.035-0.048 min -1 and complete degradation of the three EDCs after 45 min. This study provides new insights into the reactivity of combined γ-MnOOH and PMS, and opens new ways for the application of Mn-bearing species in wastewater treatment technologies., (Copyright © 2021 Elsevier Ltd. All rights reserved.)