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Item Photocatalytic degradation of ciprofloxacin & norfloxacin and disinfection studies under solar light using boron & cerium doped TiO2 catalysts synthesized by green EDTA-citrate method(Elsevier B.V., 2021) Manjunatha, M.; Chandewar, P.R.; Mahalingam, H.The presence of antibiotic residues in water bodies is an emerging global concern due to its potential development of antimicrobial resistance. Hence, it is essential to develop photocatalysts that not only degrade the antibiotics but can also simultaneously disinfect. Four different boron and cerium doped TiO2 photocatalysts, synthesized by the EDTA-citrate method, are studied for the degradation of two common fluoroquinolone-based antibiotics: ciprofloxacin (CIP) and norfloxacin (NOR) under sunlight. The catalysts are characterized by SEM, TEM, Raman spectroscopy, XPS, DRS, BET surface area and particle size analyzer. At optimized conditions, the synthesized catalysts showed 90–93% degradation for both CIP and NOR. The effects of catalyst loading and initial concentration are studied, and the reaction is found to be pseudo-first-order. The degradation is analyzed by COD reduction and LC–MS, and the by-products of degradation determined. The recycle studies showed that the catalysts are stable up to three consecutive runs. The scavenging experiments indicated e? and OH? as the dominant species responsible for the photocatalytic activity. The disinfection studies using these catalysts under solar light gave 95–99.99% efficiency for E.coli confirming that they are very efficient and can be further exploited for large scale treatment. © 2020 Elsevier B.V.Item Highly efficient solar light-driven BiOX (X=Br/Cl/I) and BiOY heterojunction (Y=Br/Cl) nano photocatalysts in suspended and immobilised forms for malachite green dye wastewater treatment(Springer Science and Business Media Deutschland GmbH, 2023) Mishra, S.; Manjunatha, M.; Mahalingam, H.A novel BiOY (Y = Br/Cl) heterojunction nanocatalyst was synthesised chemically and compared with three different BiOX (X = Br/Cl/I) nanocatalysts as well as a physical admixture of BiOBr/BiOCl catalysts in the photocatalytic degradation of malachite green dye wastewater under solar irradiation in both suspended and immobilised forms using polysulfone as the substrate. Catalyst characterisation was done by a particle size analyser, SEM/EDX, XRD, FTIR, and DRS. In the suspended form, BiOBr showed 100% degradation within 70 min, BiOCl showed 99.3%, and BiOI showed 11.2% degradation within 120 min, and it is found to follow pseudo-first-order kinetics. In the immobilised form, BiOBr showed 89.1%, and BiOCl showed 83.4% degradation within 180 min under sunlight. The degradation measured by TOC reduction for these catalysts in suspended form was 67.4%, 57%, and 40%, affirming BiOBr as the best among these catalysts. The performance of the immobilised chemically synthesised BiOY and physical admixture catalysts were 88% and 14%, respectively. The enhanced activity in the chemically synthesised immobilised BiOBr/Cl catalyst can be attributed to the effective charge separation at the heterojunction interface. These photocatalysts are very active under solar light and hence suitable for the efficient degradation of other recalcitrant organic contaminants. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Upcycling of waste EPS beads to immobilized codoped TiO2 photocatalysts for ciprofloxacin degradation and E. coli disinfection under sunlight(Nature Research, 2023) Manjunatha, M.; Mahalingam, H.The emerging global problem of antimicrobial resistance needs immediate attention. In this regard, this work demonstrates the use of expanded polystyrene waste in the synthesis of immobilized photocatalytic films for the treatment of antibiotics as well as for bacterial disinfection. A boron–cerium codoped TiO2 catalyst (of specific composition: B0.8Ce0.2TiO2) was immobilized in an expanded polystyrene (EPS) film prepared from waste EPS beads. These films were studied for the degradation of ciprofloxacin (CIP) and disinfection of E. coli under sunlight. The film with a catalyst loading of 20 wt% showed a maximum degradation of 89% in 240 min with a corresponding TOC reduction of 84%. A 7.4 and 6.3 log reduction from the bacterial inactivation studies in the presence and absence of antibiotics, respectively, was obtained. The EPS film was stable after five times of reuse, and no significant chemical changes in the used film were observed from FTIR analysis. The average thickness of the prepared film was found from FESEM analysis to be 1.09 mm. These EPS films were also tested for degradation of other antibiotics, such as norfloxacin, levofloxacin and moxifloxacin. The EPS films were tested in two different reactor volumes at optimum conditions. Also, the effectiveness of B0.8Ce0.2TiO2/EPS film in real water samples indicates its potential in large-scale and real-world applications. Thus, these B0.8Ce0.2TiO2/EPS films can be effectively employed for both degradation of ciprofloxacin and the disinfection of E. coli under solar light to solve the increasing problem of antimicrobial resistance. © 2023, Springer Nature Limited.