Removal of Lead Ions (Pb2+) Using Acid-Activated Clay from East Kalimantan

This study aims to determine the optimal conditions of acid-activated clay adsorbent in adsorption of Pb2+ metal ions. Clay was taken around East Kalimantan, Karang Joang. This adsorbent was prepared by mixing clay into a solution of KMnO4, H2SO4 and HCl successively, and stirred for 4 hours at a temperature of 80°C. The morphology and active groups of the adsorbent were analyzed using BET and FTIR. The variables of this study were the mass of the adsorbent 0.1, 0.3 and 0.5 grams and the contact time of 5, 30 and 55 minutes. Adsorption capacity of this adsorbent was analyzed using Atomic Absorption Spectrophotometry (AAS). The results of this study indicate that the optimum mass of adsorbent is 0.1 g, and contact time is 30 minutes. Adsorption capacity of Pb2+ metal ions by acid-activated clay adsorbent at the optimum condition of 0.1 gram was 23,585 mg/g and adsorption energy was 2,338 kJ/mol. Meanwhile, at the optimum condition for 30 minutes, the adsorption capacity was 0.771 mg/L, and the adsorption energy was 2.895 kJ/mol. So that the adsorption process in this study can be known, namely physical adsorption because the adsorption energy value is less than 40 kJ/mol.