Optimization of copper adsorption by chemically modified fly ash using response surface methodology modeling

Abstract

Though copper is a necessary trace element but it can be toxic in higher concentration. Locally available fly ash was found to be low-cost adsorbent to remove copper from aqueous solution. Calcium oxide-treated fly ash was investigated in the study of scale up of copper removal. Response surface methodology (RSM) was used for the statistical optimization of the copper reduction process. A two-level-three-factor (23) full factorial central composite design with the help of Design Expert Version 7.0.0 (Stat Ease, USA) was used for the optimization of the copper adsorption process variables like: initial solution pH (3.5–5.5), initial copper concentration (15–50 mg/L), and contact time (45–90 min) and to evaluate the effects and interactions of process variables. The optimum reduction of copper was 99.16% at pH 3.98, 77.88 mg/L copper concentration, and 58.82 min of contact time. The percentage deviation between experimental and RSM model equation was 0.03%.