Faculty Publications
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Item Enhanced disinfection of E. faecalis and levofloxacin antibiotic degradation using tridoped B-Ce-Ag TiO2 photocatalysts synthesized by ecofriendly citrate EDTA complexing method(Springer Science and Business Media Deutschland GmbH, 2022) Sekar, P.; Sadanand Joshi, D.; Manjunatha, M.; Mahalingam, H.Since its use for photochemical water splitting reported first in 1972, TiO2 is one of the most extensively studied photocatalysts for a diverse range of applications. Monodoping or codoping of the catalyst is a proven strategy to enhance the functionality of TiO2 under solar or visible light. However, the use of three or more dopants in the development of more efficient and visible light active photocatalysts has not been investigated widely, especially for microbial disinfection. Boron/cerium/silver tridoped TiO2 photocatalysts with curated amounts of the dopants (B = 1, 2 at.%, Ce = 0.1 at.%, Ag = 0.06 at.%), synthesized by the ecofriendly EDTA-citrate method, were evaluated for the disinfection of water using Enterococcus faecalis under UV-A irradiation and degradation of levofloxacin antibiotic under solar light. The catalyst characterization revealed that the spherical nanoparticles had a crystallite size of ~ 13 nm and bandgap energy values of 2.8–2.9 eV. 2B-0.1Ce-0.06Ag-TiO2 is the best catalyst for microbial disinfection with a log reduction and kinetic rate constant ~ 30 and ~ 4.5 times higher than those values determined for the other codoped or monodoped catalysts, confirming an enhanced performance. Regarding levofloxacin degradation, the best performing catalyst is 1B-0.1Ce-0.06Ag-TiO2 with degradation of 99% and 83% COD reduction in 100 min. The tridoped photocatalysts are very effective in the inactivation of Enterococcus faecalis, thus solving the problem of antimicrobial resistance in waters containing antibiotic residues. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.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.