PHOSPHATE REMOVAL BY ELECTROCOACULATION

Abstract

The present investigation deals with phosphate reduction from synthetic waste water in a batch electrocoagulation (EC) reactor using aluminium and iron electrodes. Central composite (CC) experimental design was employed to evaluate the individual and interactive effects of four independent parameters on the phosphate removal efficiency. The parameters studied were initial pH (pHo); 2-10, time (t); 10-50min, initial phosphate concentration (C); 10-100mg/1, current density (j); 2-20A/m2. Experiments were carried out in a 1.94 1 (1 lcmx11 cmx16cm) rectangular reactor made up of Perspex glass. Iron and aluminium plates of thickness 1 mm were used as electrodes. Dimensions of electrodes were 8.0 cmx8.0 cm; area of electrodes dipped into the solution was 8.0cmx8.0cm. The total effective surface area of each electrode was 128cm2. Results were analyzed using Pareto analysis of variance (ANOVA). Analysis showed a high coefficient of determination value (R2=87.6% and R2=83.8%) for Al and Fe electrode respectively and satisfactory prediction for second order regression model. Graphical response surface plots were used to locate the optimum values of studied parameters. Maximum phosphate reduction of 93.11% for Al electrodes and 98.16% for Fe electrodes was observed at optimum conditions.