Application of statistical design of experiment with desirability function for the removal of organophosphorus pesticide from aqueous solution by low-cost material

This paper deals with the multiple response optimization for the removal of organophosphorus pesticide quinalphos [QP: O,O-diethyl O-2-quinoxatinyl phosphorothioate] from the aqueous solution onto low-cost material and tried to overcome the drawbacks of univariate optimization. Used tea leaves were used as low-cost adsorbent and batch equilibration method was followed for this study. A Box-Behnken design was used to develop response model and desirability function was then used for simultaneous optimization of all affecting parameters in order to achieve the highest removal% of quinalphos. The optimum conditions of factors predicted for quinalphos removal% were found to be: pH 8.83, concentration 7 mg L-1 and dose 0.40 g. Under these conditions, maximum removal% of quinalphos was obtained 96.31%. Considering the above optimum conditions. the adsorption isotherms were developed and provided adsorption capacity of 196.07 mu g g(-1) by using Langmuir equation, indicating that used tea leaves may be applied as a low-cost material for pesticides removal from aqueous matrices. (C) 2009 Elsevier B.V. All rights reserved.