Photocatalytic degradation of dimethoate using LbL fabricated TiO2/polymer hybrid films

Priya, Neela D and Modak, Jayant M and Trebse, Polonca and Zabar, Romina and Raichur, Ashok M (2011) Photocatalytic degradation of dimethoate using LbL fabricated TiO2/polymer hybrid films. In: Journal of Hazardous Materials, 195 . pp. 214-222.

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Abstract

Degradation of dimethoate under UV irradiation using TiO2/polymer films prepared by the layer-by-layer (LbL) method was investigated. The thin films were fabricated on glass slides and the surface morphology and roughness of the thin films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effect of lamp intensity, catalyst loading in the layers, number of bilayers, pH and initial dimethoate concentration on the degradation of dimethoate was systematically studied. The degradation was monitored using high performance liquid chromatography (HPLC) analysis and total organic carbon (TOC) measurements as a function of irradiation time, to see the change in concentration of dimethoate and mineralization, respectively. Complete degradation of dimethoate was achieved under TiO2 optimum loading of 4 g/L at an UV irradiation time of 180 min. Increase in the lamp intensity, catalyst loading and number of bilayers increased the rate of degradation. At a pH of 4.62, complete degradation of dimethoate was observed. The degradation efficiency decreased with increase in initial dimethoate concentration. The degradation byproducts were analyzed and confirmed by gas chromatography-mass spectra (GC-MS). Toxicity of the irradiated samples was measured using the luminescence of bacteria Vibrio fischeri after 30 min of incubation and the results showed more toxicity than the parent compound. Catalyst reusability studies revealed that the fabricated thin films could be repeatedly used for up to ten times without affecting the photocatalytic activity of the films. The findings of the present study are very useful for the treatment of wastewaters contaminated with pesticides. (C) 2011 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	Journal of Hazardous Materials
Publisher:	Elsevier Science B.V.
Additional Information:	Copyright of this article belongs to Elsevier Science B.V.
Keywords:	Layer-by-layer method;Photocatalysis;TiO2;Dimethoate; Immobilized catalyst
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	09 Mar 2012 10:38
Last Modified:	03 Jan 2013 04:55
URI:	http://eprints.iisc.ac.in/id/eprint/43871

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