Application of activated carbon from banana stem waste for removal of heavy metal ions in greywater using a Box–Behnken design approach

Abstract

There is limited information on the optimal processes to remove heavy metals in greywater. A Response Surface Methodology (RSM) via the Box–Behnken Design (BBD) approach was applied in this study to investigate and optimise the process variables of activation time (1.5–2.5 h), impregnation ratio (0.25–0.75) and zinc chloride (ZnCl2) percentage (20–60%) for the removal of heavy metal ions (Cd, Cu, Pb and Ni) associated with greywater treatment. The quadratic model was chosen to describe the effects of the process variables (activation time, impregnation ratio, ZnCl2 percentage) on predicting the responses (heavy metal ions removal) with low p-values (