Title: Phosphotungstic acid supported on chitosan/SiO₂ composite for photocatalytic degradation of tetraazo dye direct fast black G

Authors: Kebin Li; Yanhui Zhang; Qinqin Wang; Hong Wei; Feng Zhao; Tao Zhang

Addresses: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, School of Chemistry and Material Science, Northwest University, Xi'an 710069, China ' Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, School of Chemistry and Material Science, Northwest University, Xi'an 710069, China ' Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, School of Chemistry and Material Science, Northwest University, Xi'an 710069, China ' Department of Municipal and Environmental Engineering, Xi'an University of Technology, Xi'an 710048, China ' Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, School of Chemistry and Material Science, Northwest University, Xi'an 710069, China ' Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, School of Chemistry and Material Science, Northwest University, Xi'an 710069, China

Abstract: A facile process to prepare the supported phosphotungstic acid/chitosan-coated silica gel composite catalyst (PW₁₂/CST/SiO₂) was presented. SEM-EDX, UV-vis DRS, FT-IR and XRD analyses revealed that PW12 was highly dispersed on CST/SiO₂ composite support's surface with the intact Keggin units. The effects of pH, dye concentration, and catalyst loading on adsorption and photodegradation of a tetraazo dye direct fast black G (DB19) by the prepared composite catalyst in the presence of electron donor (isopropanol) were investigated. The kinetics of dye adsorption and photodegradation were analysed by the zero-order kinetic model, and the corresponding rate constants were calculated. The optimal condition for the photocatalytic degradation of DB19 was also established. This study further indicates that PW₁₂/CST/SiO₂ could be used as a bifunctional material to decolourise azo dye in aqueous solutions by a combined adsorption and photocatalytic degradation process.

Keywords: phosphotungstic acid; dye photodegradation; azo dye; chitosan; silicon dioxide; silica gel; composites; kinetics; dye adsorption; kinetic modelling; photocatalytic degradation.

DOI: 10.1504/IJNM.2014.059001

International Journal of Nanomanufacturing, 2014 Vol.10 No.1/2, pp.94 - 109

Received: 26 Dec 2012
Accepted: 26 Mar 2013
Published online: 17 May 2014 *

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