STUDY ON THE ADSORPTION/REGENERATION OF SO2 OVER PYROLUSITE DOPED WALNUT SHELL ACTIVATED CARBON

Pyrolusite-doped walnut shell activated carbon (P/AC) was prepared by a blending method. Four subsequent adsorption/regeneration of SO2 over prepared activated carbon samples were studied to evaluate its performance. The initial sulfur capacity of P/AC was 257.4 mg/g, which was 62.3% higher than that of blank activated carbon. When water-washed method was employed for activated carbon regeneration, the sulfur capacity of the P/AC sample remained stable (around 169 mg/g) after the first two cycles of regeneration/desulfurization, while for blank samples, a consistent decrease of sulfur capacity was observed after each cycle of regeneration. After the fourth cycle of regeneration, the sulfur capacity of blank AC was 109.6 mg/g, which was 54.7% lower than that of the P/AC. This result indicated that the P/AC sample prepared using the blending method had the advantage of simple preparation process, good desulfurization performance, and higher economic value. The good desulfurization performance presented by P/AC after few cycles of regeneration was mainly due to the insignificant change of activated carbon surface properties and the relatively stable metal concentration that remained on the carbon samples, which kept relatively high catalytic activity, even after cycles of regeneration.