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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 Exploring the Synergy of B, Ce Dopants in Codoped Titanium Dioxide Multifunctional Photocatalysts for Antibiotic Degradation and Microbial Disinfection Under Solar Light(John Wiley and Sons Inc, 2022) Manjunatha, M.; Chandewar, P.R.; Mahalingam, H.An eco-friendly, controllable citrate-EDTA complexing sol–gel method is employed to systematically synthesize a series of BxCe1−xTiO2 (x = 0.9, 0.8, 0.7 at%) codoped photocatalysts. The degradation of ciprofloxacin (CIP) and norfloxacin (NOR) antibiotics, as well as Escherichia coli disinfection under sunlight, is assessed using these synthesized codoped photocatalysts. After physicochemical characterization of the synthesized catalysts for particle size, surface area, morphology, crystal structure, surface chemistry, bandgap energy values, and recombination, it is evident that the codoping has improved the visible light absorption, reduced the recombination, and promoted higher crystallinity as well as anatase phase content. The codoped catalysts also demonstrate an enhanced photocatalytic activity under solar light with regard to the degradation of the chosen antibiotics when compared to the performance of the monodoped counterparts or the latest generation catalysts from the literature. The highest degradation performance (≈98%) is shown by B0.8Ce0.2TiO2 in the case of CIP and B0.9Ce0.1TiO2 in the case of NOR. Also, in the case of microbial disinfection, these codoped catalysts are much better (by a factor of ≈10) than that of the monodoped catalysts. © 2021 Wiley-VCH GmbH.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 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.