Adsorptive removal of heavy metal from electroplating effluents by Agro-industrial waste adsorbent

Abstract

Cr (VI) is toxic and, in the absence of proof to the contrary, is considered carcinogenic. Of concern are its prevalence in various industrial effluents, namely electroplating, textile dyeing, leather tanning, wood treatment, refractory and metallurgy. Conventional treatment of two-stages chemical reduction and precipitation involves excess consumption of reducing agents due to the presence of dissolved oxygen in Cr waste streams; limited reduction of dissolved metal concentration with respect to the solubility product level as well as production of sulfides and voluminous sludge. Surplus, lowvalue agro-industrial by-products can be made into sorbent materials which are utilized in environmental remediation. This study characterized and evaluated oil palm empty fruit bunch (EFB) as adsorbent in adsorption of Cr (VI) from synthetic electroplating effluents. Simple chemical modification; i.e. acid and heat treatment was conducted to enhance the adsorptive capacity of EFB, thereby sustaining its economic value. Batch equilibrium tests were carried out at different temperatures (i.e. 30, 40 and 50C); thus allow the investigation of adsorption isotherms and thermodynamic parameters.