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Author: search.filters.author.Rathna, T.Subject: search.filters.subject.% reductions

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    Fabrication of visible-light assisted TiO2-WO3-PANI membrane for effective reduction of chromium (VI) in photocatalytic membrane reactor
    (Elsevier B.V., 2021) Rathna, T.; JagadeeshBabu, J.; RubenSudhakar, D.
    In this work, TiO 2-WO3(40:1) nanoparticles were hydrothermally prepared and, embedded in Polyaniline (PANI) membrane with varying concentrations (3–7 wt%) and, used in photocatalytic membrane reactor for the removal of Cr(VI) from the aqueous solutions. 4-methyl piperidine (4-MP) was used as a gel inhibiting agent in N-methyl-2-pyrrolidone (NMP) solvent to prepare PANI-based flat-sheet membranes by phase inversion method. Through different characterization technique, it has been found that TiO 2-WO3 incorporated PANI membranes showed enhanced membrane properties like better hydrophilicity, better antifouling properties, higher water uptake, lower contact angle, higher porosity, and better heavy metal removal efficiency compared to bare PANI membranes. PANI membrane with 5 wt% TiO 2-WO3 exhibited a percentage rejection of 98.50% within 60 min at 0.5 MPa transmembrane pressure. Cr(VI) reduction under light and dark conditions was performed in a dead-end filtration cell with a quartz window at the top and the 5 wt% TiO 2-WO3– PANI membrane showed 67.32% reduction under visible light. TiO 2-WO3 incorporated PANI nanofiltration membranes can act as an integrated system consists of a short-circuited photo-anode and cathode under visible light irradiation. Overall, TiO 2-PANI membranes promote Cr(VI) reduction to Cr(III) in the photocatalytic membrane reactor and exhibits a better self-cleaning property. © 2021
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    Synthesis, Characterization and Performance Evaluation of TiO2-SnO2 photocatalyst for Removal of Toxic Hexavalent Chromium
    (Springer Science and Business Media Deutschland GmbH, 2022) Rathna, T.; JagadeeshBabu, J.B.; Ruben Sudhakar, D.R.
    Heavy metal pollution bears a substantial threat to flora, fauna, humans, and milieu. The elimination of hexavalent chromium [Cr(VI)] from polluted water is of considerable research interest from a health and environmental viewpoint. This work aims for photocatalytic reduction of Cr(VI) to Cr(III) using TiO2 and SnO2 as catalysts. The process parameters varied are catalyst dosage, pH, initial concentration of model pollutant with citric acid (CA) as a scavenger. TiO2-SnO2 (in the molar ratios 10:1, 20:1, 30:1, and 40:1)-based catalysts were synthesized using the hydrothermal method. The 40:1 catalyst showed higher photoactivity than other catalysts and could extend the optical activity in the visible light region. The complete reduction of Cr(VI) with a concentration of 15 mg/L and pH 3.0 was achieved when catalyst concentration was 0.6 g/L over a period of 30 min. The XRD (X-Ray Diffraction Spectroscopy) and ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy) results confirm the Ti-Sn heterojunction formation, and XPS (X-ray Photoelectron Spectroscopy) analysis corroborate the presence of trivalent chromium [Cr(III)] on TiO2-SnO2 catalyst after reduction. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
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    TiO2-WO3 nanocube-polyaniline hierarchical membrane for efficient removal of chromium in a photocatalytic membrane reactor
    (John Wiley and Sons Inc, 2023) Rathna, T.; JagadeeshBabu, J.; Ruben Sudhakar, D.R.
    In this article, the rational design of a physically coated TiO2-WO3 nanocube-polyaniline photocatalytic membrane (hierarchical) reactor for the efficient reduction of chromium (VI) under visible light is discussed. The incorporation of TiO2-WO3 in the polyaniline (PANI) membrane provides excellent hydrophilicity and high photo-corrosion resistance and facilitates the rapid permeation of water with a flux rate of 12 L/m2 h and higher Cr (VI) reduction. The exposure of bare PANI membranes in Cr (VI) solution leads to over-oxidation of PANI membrane and eventually leads to the destruction of the membrane. The hierarchical photocatalytic coating improves the lifetime of the membrane by blocking it from deprotonation. The photocatalytic membrane could offer 79.30% Cr (VI) reduction under visible light irradiation in a photocatalytic membrane reactor. After several reduction cycles, the membrane showed good self-cleaning ability. The present work suggests that TiO2-WO3 nanocube-coated PANI hierarchical membrane is a promising approach for the reduction and removal of Cr (VI) from wastewater. © 2023 CIWEM.