Influence of Impregnation Ratio on the Properties of Activated Carbon Prepared via ZnCl2 Activation

In this study, an activated carbon with high surface area was prepared from walnut shell by chemical activation using ZnCl2. Impregnation ratios of activating agent to dry precursor (wt/wt) were selected in the range of 0.5–2.0. The influences of impregnation ratio on the characterization of the activated carbon were investigated by SEM (scanning electron microscopy), FTIR (transmittance Fourier infrared spectroscopy) and XRD (X-ray diffraction) analysis. The SEM analysis shows there is a good and successful pore development in the activated carbon obtained with increasingimpregnation ratios. X-ray diffraction patterns showed broad peaks, that suggesting either that structure is amorphous or that the particles are really too small particles or too low concentration of adsorbed material to diffract. The surface areas of the activated carbons increased with increasing impregnation ratios and the maximum value of the BET surface area can reach 2643 m2/g at impregnation ratio 2:1. The FTIR analysis showed that at high impregnation ratios the formation of aromatic rings was favored, while the formation of acidic surface groups was favored at lower impregnation ratios. Efficiency of activated carbon production has shown an optimum impregnation ratio of 2:1.

Keywords:

Activated carbon , Walnut shell , ZnCl2 , Impregnation , Adsorbent