BENZENE ADSORPTION ON ACTIVATED CARBON FROM WALNUT SHELL

Abstract

The adsorption ability of activated carbon derived from walnut shell was investigated for removal of benzene existing in the rich amine stream of gas sweetening systems. Carbonaceous samples derived from Iranian walnut shell (WS) were prepared by the chemical activation method using ZnCl2 and H3PO4 as activating agents. Impregnation ratio, activation temperature, and retention time in the final temperature were studied as operating variables based on the Taguchi method. The obtained activated carbons were characterized by measuring their characteristics by scanning electron microscopy (SEM), FT-IR, BET, and iodine number techniques. According to the results, carbon activated by H3PO4 has higher BET surface area (1544 m2/g), while carbon activated by ZnCl2 has better ability for removal of benzene (about 61.22 mg/g in an initial concentration of 300 mg/L). Benzene uptake was found to increase with increase in initial concentration and contact time. Kinetic and equilibrium adsorption studies were investigated.