Removal of As(V) using low cost adsorbents: aerocrete and vermiculite modified with iron oxy-hydroxide

The present study highlights performance of two adsorbents, namely aerocrete and vermiculite, modified with iron oxyhydroxide for removal As(V) from aqueous solution. A face-centered central composite design of response surface methodology (RSM) was employed to optimize efficacy of three experimental variables, adsorbent dosage, pH and initial As(V) concentration, and simultaneously the interactive effects of these variables on As(V) adsorption process were studied. The analysis of variance (ANOVA) of quadratic model shows that the predicted values are in good agreement with experimental data. The results show the leading effect of adsorbent dosage and initial As(V) concentration as well as interactive effect of these two variables on As(V) removal efficiency. Maximum As(V) removal 99.96% and 98.95% are obtained respectively for modified aerocrete and vermiculite at pH of 6, adsorbent dose of 3.1 g/l and initial As(V) concentration of 12 mg/l (ppm). The adsorption data are well fitted with the Langmuir and Freundlich isotherms.