Adsorption of Pb (II) ions by activated and modified candlenut shell based carbon

Abstract

A research on the adsorption of Pb2+ ions by candlenut shell carbon that was activated with 10% ZnCl2 and then modified with HNO3 has been done. The candlenut shell was carbonized at 400°C before activation and surface modification. Characterization of the carbon was carried out by surface area test using methylene blue method, identification of functional groups using Fourier Transform Infrared (FTIR) and adsorption experiment at optimum condition. The concentration of Pb (II) ions was determined by Atomic Absorption Spectrophotometer (AAS). Surface area of carbon, activated carbon and modified activated carbon are 503.57 m2/g, 516.63 m2/g and 524.86 m2/g, respectively. Boehm titration and FTIR analysis results showed that functional groups such as -OH (in carboxylic acid and phenol) and C=O (in lactone) increased after modification with HNO3. Based on analysis using AAS, the optimum adsorption time was 30 minutes and the optimum pH was 4. The adsorption capacity of Pb2+ ions by modified activated carbon was higher than un-modified activated carbon.