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Environmental Pollution (Barking, Essex... Mar 2024Indirect photolysis induced by naturally occurring sensitizers constitutes an important pathway accounting for the transformation and fate of many recalcitrant...
Indirect photolysis induced by naturally occurring sensitizers constitutes an important pathway accounting for the transformation and fate of many recalcitrant micropollutants in sunlit surface waters. However, the photochemical transformation of micropollutants by photosensitizing pharmaceuticals has been less investigated. In this study, we demonstrated that the non-steroidal anti-inflammatory drug ketoprofen (KTF) and its photoproducts, 3-acetylbenzophenone (AcBP) and 3-ethylbenzophenone (EtBP), could sensitize the photodegradation of coexisting sulfonamide antibiotics, e.g., sulfamethoxazole (SMX), under artificial 365 nm ultraviolet (UV) and sunlight irradiation. Key reactive species including triplet excited state and singlet oxygen (O) responsible for photosensitization were identified by laser flash photolysis (LFP) and electron paramagnetic resonance (EPR) techniques, respectively. High-resolution mass spectrometry (HRMS) and structure-related reactivity analyses revealed that the sensitized photolysis of SMX occurred mainly through single electron transfer. The rate constants of sulfonamides sensitized by AcBP photolysis followed the order of sulfisoxazole (SIX)>sulfathiazole (STZ)>SMX>sulfamethizole (SMT). Exposure to sunlight also enhanced the photolysis of SMX in the presence of KTF or AcBP, and water matrix had limited impact on such process. Overall, our results reveal the feasibility and mechanistic aspects of photosensitization of coexisting contaminants by pharmaceuticals (or their photoproducts) and provide new insights into the cocktail effects of pharmaceutical mixtures on their photochemical behaviors in aqueous environment.
Topics: Anti-Bacterial Agents; Photolysis; Ketoprofen; Sulfonamides; Sulfanilamide; Sulfamethoxazole; Water; Pharmaceutical Preparations; Water Pollutants, Chemical
PubMed: 38290656
DOI: 10.1016/j.envpol.2024.123458 -
Environmental Research Jun 2024A novel photocatalyst InO with loading Ag particles is prepared via a facile one-step annealing method in air atmosphere. The Ag/InO exhibits considerable photoactivity...
A novel photocatalyst InO with loading Ag particles is prepared via a facile one-step annealing method in air atmosphere. The Ag/InO exhibits considerable photoactivity for decomposing sulfisoxazole (SOX), tetracycline hydrochloride (TC), and rhodamine B (RhB) under natural sunlight irradiation, which is much higher than that of pristine InO and Ag species. After natural sunlight irradiation for 100 min, 70.6% of SOX, 65.6% of TC, and 81.9% of RhB are degraded over Ag/InO, and their corresponding chemical oxygen demand (COD) removal ratio achieve 95.4%, 38.4%, and 93.6%, respectively. A batch of experiments for degrading SOX with adjusting pollutant solution pH and adding coexisting anions over Ag/InO are carried out to estimate its practical application prospect. Particularly, the as-prepared Ag/InO possesses a superior stability, which exhibits no noticeable deactivation in decomposing SOX after eight cycles' reactions. In addition, the Ag/InO coated on a frosted glass plate, also possesses a superior activity and stability for SOX removal, which solve the possible second pollution of residual powdered catalyst in water. Ag particles on InO working as electron accepter improve charge separation and transfer efficiency, as well as the photo-absorption and organic pollutants affinity, leading to the boosted photoactivity of Ag/InO. The photocatalytic mechanism for degrading SOX and degradation process over Ag/InO has been systemically investigated and proposed. This work offers an archetype for the rational design of highly efficient photocatalysts by metal loading.
Topics: Silver; Sunlight; Water Pollutants, Chemical; Catalysis; Rhodamines; Photolysis
PubMed: 38458589
DOI: 10.1016/j.envres.2024.118649 -
Environmental Research Jun 2024In recent studies, carbon nanotube (CNTs) materials and their composites have demonstrated remarkable catalytic activity in the activation of persulfate (PS),...
In recent studies, carbon nanotube (CNTs) materials and their composites have demonstrated remarkable catalytic activity in the activation of persulfate (PS), facilitating the efficient degradation of organic pollutants. In this study, a novel Co loaded carbon nanotubes (CoO@CNT) catalyst was prepared to promote PDS activation for the degradation of sulfafurazole (SIZ). Experimental results, the CNT as a carrier effectively reduces the leaching of cobalt ions and improves the electron transport capacity,whereas the introduced Co effectively activates the PDS, promoting the generation of highly reactive radicals to degrade SIZ. Under optimized conditions (a catalyst dose of 0.2 g/L, a PDS dose of 1 g/L and an initial pH = 9.0), the obtained CoO@CNT demonstrated favorable Fenton-like performance, reaching a degradation efficiency of 95.55% within 30 min. Furthermore, density functional theory (DFT) calculations demonstrate that the introduction of cobalt (Co) accelerates electron transfer, promoting the decomposition of PDS while facilitating the Co/Co redox cycling. We further employed the environmental chemistry and risk assessment system (ECOSAR) to evaluate the ecological toxicity of intermediate products, revealing a significant reduction in ecological toxicity associated with this degradation process, thereby confirming its environmental harmlessness. Through batch experiments and studies, we gained a comprehensive understanding of the mechanism and influencing factors of CoO@CNT in the role of SIZ degradation, and provided robust support for evaluating the ecological toxicity of degradation products. This study provides a significant strategy for the development of efficient catalysts incorporating Co for the environmentally friendly degradation of organic pollutants.
Topics: Nanotubes, Carbon; Cobalt; Catalysis; Sulfates; Oxides; Water Pollutants, Chemical; Oxidation-Reduction
PubMed: 38485075
DOI: 10.1016/j.envres.2024.118646