Adsorption of Copper from Waste Printed Circuit Boards with Modified Orange Peels

Abstract

Copper adsorption from waste printed circuit boards (PCBs) was studied using biosorbents derived from waste orange peels (OP). The orange peels were modified by different methods including saponification with NaOH (OP-S), crosslinking with sodium trimetaphosphate and sodium tripolyphosphate (OP-C), hydroxypropylation with propylene oxide (OP-H), and acidification with citric acid (OP-A) to increase the adsorption capacity of orange peels. Adsorption tests on the copper (Cu) model solutions were performed by using native and modified orange peels at three different temperatures (25 degrees C, 40 degrees C, and 60 degrees C) to determine the optimum adsorption conditions. The PCB was pyrolyzed in a fixed bed stainless steel reactor to obtain a solid product that contained only inorganic material. Metals were then leached from the solid product, and adsorption studies were realized on the leach solution under optimum adsorption conditions. According to the analyses results, the best adsorption efficiency for the Cu model solution was obtained with OP-S at 25 degrees C for 30 min. Under these conditions, the Cu adsorption efficiency from pyrolysis solid product was approximately 86%.