Removal of zinc (II) from model wastewater using processed Moringa oleifera Lam. Seeds: Optimization study using central composite design (CCD) and response surface methodology

Abstract

This study investigated the effectiveness of processed Moringa oleifera Lam. seeds as bioactive constituents (biosorbent) for zinc (II) removal in wastewater. Previous studies reported significance adsorptions on heavy metals using salt extracted bioactive compounds. Thus, it was followed in this study by a process of ultrafiltration to obtain higher and purer yield compounds. Method analysis developed using second order polynomial (quadratic) model of Central Composite Design (CCD) observed significant interactions between the rate of zinc (II) removal with amount of bioactive dosage and pH applied. Optimization study using CCD has achieved the final residual of 98.33% removal which agreed with the predicted model value. Therefore, the method was proven to be successful in reducing average zinc(II) concentrations in wastewaters (initial of 3 mg/L) thus fulfilling regulation for maximum discharge limit of 1 mg/L under Malaysia-Environment Quality Act 1974 (Sewage and Industrial Effluents) .