Adsorption of Some Heavy Metals from Wastewater using Fine Sand and Zeolite

Abstract

In this study, successive columns containing different types of solid state materials were used to investigate the treatment efficiency of soya bean oil mill wastewater (soap stock) using heavy metals analysis. Soap stock is a liquid waste obtained from soya bean oil industry from the neutralization process which has several environmental issues due to its high amount of organic and inorganic pollutants. Soap stock emerges from the refining process when oil is treated with a dilute alkali solution separating the FFAs as soaps. In this present study, an attempt was made at treating the wastewater using successive columns containing different types of solid state materials. The wastewater was passed through successive columns of fine sand, Zeolite and Zeolite/fine sand composite.. This treatment method decreased the toxic concentration of heavy metals assessed which include Pb, Cu, Zn, Ni and Cd by mean percentages of 96.60%, 100%, 62.0%, 16.10% and 96.60% respectively. Most contaminants were removed in the Zeolite/sand composite column possibly as a result of ion exchange capacity in addition to high sorption affinity of Zeolite on its active sites. This simple Zeolite based method enable us to obtain environmentally friendly treated soya bean oil water that can be safely used for irrigation purposes.