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The development of low-cost, efficient and sustainable technology is considered to be of paramount for the efficient degradation of toxic pollutants. The research in this report constructs an S-scheme heterojunction CoO/ZnFe2O4 nanocomposite (NCs) with outstanding photocatalytic performance on methylene blue (MB) dye degradation under visible light illumination. Several techniques were used for nanoparticles (NPs) and NCs to determine their morphological, structural, and optical properties. The CoO/ZnFe2O4 NCs (88.5%) exhibited excellent photocatalytic activity compared to the pristine CoO (66.8%) and ZnFe2O4 (64.3%). The total organic carbon (TOC) analysis confirmed that the MB dye was completely mineralised by the as-prepared NCs. From the results of the GC-MS/MS analysis, a possible intermediate formation and degradation pathway was identified. The h+ and ˙OH are the free radicals which primarily dominate the photocatalytic process. A recyclability study performed on the CoO/ZnFe2O4 NCs revealed that it was an extremely stable catalyst, even after six cycles, without substantial decreases in its degradation activity. The intermediate toxicity was predicted using ECOSAR software and the results confirmed the non-toxicity of the end product formed during the degradation of the MB dye. [ABSTRACT FROM AUTHOR]

In this study, a magnetic Fe3O4–CeO2 nano-heterojunction was fabricated on an organic matrix cetyl trimethylammonium bromide (CTAB) using a sonochemical method. The resulting nanocomposites (NCs) were used for the synergetic removal of tetracycline by adsorption and photocatalysis and their antimicrobial applications were also investigated. The average diameter and zeta potential of the NCs were 46 ± 2 nm and −33.24 ± 1.34 mV, respectively. The presence of the CTAB matrix was verified by FTIR analysis. The adsorption of tetracycline on the NCs was well fitted to the Langmuir model. The maximal adsorption was noted at pH 5. The photocatalytic degradation of tetracycline (25 mg L−1) by the NCs (10 mg L−1) reached 96.6% in 3 h under visible-light irradiation. The photocatalysis mechanism followed the S-scheme by retaining the photo-excited e−/h+ pairs with strong redox potential. The particles exhibited excellent antibiofilm and antibacterial activities. There was increased ROS generation and lipid peroxidation in the bacterial species upon exposure to the NCs. The bacterial antioxidant defense systems were disturbed upon exposure to the NCs. Therefore, the as-prepared Fe3O4–CeO2-CTAB NCs could be used as a promising candidate in wastewater treatment for disinfection applications and the adsorptive/photocatalytic removal of pharmaceuticals. [ABSTRACT FROM AUTHOR]

In the present work, ternary CoCr2O4–Bi2WO4–NiS2 nanocomposite (CCO–BWO–NS NC), a semiconductor photocatalyst, was prepared for the effective mineralization of doxycycline and photocatalytic removal of Cr(VI). Here, the modification of BiO–WO4–BiO (BWO) as a sandwich structure caused higher lattice oxygen vacancies. The decoration of NiS2 (NS) on CCO–BWO enhanced the photocatalytic activity of the NC under visible-light irradiation. The photocatalytic degradation efficiency of doxycycline (doxy) and removal of Cr(VI) by the CCO–BWO–NS NC was found to be 99.8% and 94.7%, respectively. The subsurface and solid solution-type defect engineering was determined by X-ray photoelectron spectroscopy (XPS). Density function theory (DFT) calculations enabled the band structure and defect mechanism of the CCO–BWO–NS NC to be determined. Further, the photocatalytic efficiency was studied by varying the pH in the degradation of doxy and removal of Cr(VI). The total organic carbon (TOC) reduction after doxy photodegradation was found to be 98.6%. In addition, the genotoxicity of the CCO–BWO–NS NC was determined and the results showed that the CCO–BWO–NS NC had a comparatively lower genotoxicity and mitotic index, and no micronuclei were observed. Thus, the prepared CCO–BWO–NS NC was found be an excellent photocatalyst for the effective removal of doxy and Cr(VI). The study suggests that the CCO–BWO–NS NC could be an excellent photocatalyst for environmental water treatment. [ABSTRACT FROM AUTHOR]