Comparative studies on bentonite clay and peanut shell carbon recovering heavy metals from printed circuit boards

Abstract

The quantity of electronic waste subjected to disposal annually is increasing alarmingly and is of major environmental concern due to the existence of heavy metals and other toxic substances. In this present study, by combining leaching and adsorption the recovery of heavy metals from Printed circuit boards (PCBs) has been performed. The two stage aqua-regia leaching extracts Copper (Cu), Tin (Sn), Lead (Pb), and Zinc (Zn) from PCB. Bentonite Clay (Bent) and Peanut Shell Carbon (PSC) in their pristine, thermally and chemically activated forms were employed as adsorbents to remove the heavy metals from leached solution. Effect of parameters (contact time, temperature, adsorbent dosage and size) on % adsorption was studied. Chemically activated bent (C-A Bent) has proven to be an effective among all adsorbents studies with % adsorption for Cu 97%, Sn 98%, Zn 96%, and Pb 96%. Leaching and adsorption combination can become a promising methodology for handing electronic waste.