Photocatalytic degradation of aqueous styrene in visible lightusing design of experiment

In thisstudy, the center compositedesign in response surface methodologywasfirstlyapplied to optimize the photocatalytic degradation of aqueous styrene undervisible light. Twentyexperimentswere doneby adjusting threeparameters (initial concentrationof styrene,concentration of catalystand initial pHof reaction mixture) at fivelevels bythemethod ofmultiple variableanalyses. Based on the experimental design, an empirical expression was firstlyestablished and subsequently applied to predict the photocatalytic degradation efficiencyof aqueous styreneunder visible light. Theresultsshowedthatthe experimental photocatalytic degradationefficienciesare in accordancewith thetheoretically predicted values very well with a highcorrelation.The strongest interaction between the parameters assessed was concentration of catalyst/initial pHof mixture.Optimal experimental conditions for arbitrary aqueousstyreneconcentration of 115 mgL−1 werefoundinitial pH 6.8and catalystloading 2 gL−1. The hotocatalyticdegradation efficiencyof aqueousstyreneunder this conditionreachedtoabout84%.Furthermore, the main degradation intermediate produced in this process was identified by GC/MS technique. The photocatalytic mineralization of styrene in aqueous solution has been studied by TOC.

Keywords:

AqueousStyrene , Photocatalytic degradation , visible light , design f experiment