A Remediation Study Using Moringa oliefera Seed (Uncarbonised and Carbonised) for the Adsorption of Chromium, Cadmium and Lead from Synthetic Water

Abstract

Moringa oleifera seed was treated and activated to prepare low-cost adsorbents whose adsorption properties would be compared. The uptake for lead, chromium, and cadmium from aqueous solution using the Moringa oleifera seeds biomass (MOS) and Moringa oleifera seed charcoal (CMOS) was studied. CMOS was prepared from MOS in order to make better use of this biomass material. Batch experiments were conducted under varying MOS/CMOS adsorbent dosages (0.5-1.5 g), contact time (30 min–6 hr) and metal ion concentrations (1-50 ppm) for chromium, lead and cadmium. The data for MOS fit well with Langmuir isotherm model for lead (maximum metal uptake (Qm) = 1.281 mg/g) and Cadmium (maximum metal uptake (Qm) = 0.168 mg/g) whereas CMOS can be modelled by both Freundlich and Langmuir isotherms for chromium (adsorption capacity = 0.2202 mg/g) and Lead (maximum metal uptake (Qm) = 0.552 mg/g) respectively. However, the biomass of MOS was found to be more suitable than CMOS for the development of an efficient adsorbent for the removal of chromium, lead and cadmium from aqueous solutions. This study demonstrated that both the charcoal and uncarbonised biomass could be used as adsorbents for the treatment of Cr, Pb and Cd from aqueous solution.