Adsorbent prepared from sewage sludge by chemical activation and its application to sulfur dioxide adsorption

Textural characteristics of adsorbent derived from sewage sludge by chemical activation with ZnCl2 solution were investigated. The effects of hold time, pyrolysis temperature and ZnCl2 solution concentration on the specific surface area (BET method) of adsorbent derived from sewage sludge were also studied. Keeping the hold time for 2 h, pyrolysis temperature at 850°C and ZnCl2 concentration of 3 mol/L, the specific BET surface area achieves 550 m²·g^-1. Dynamic adsorption test for sulfur dioxide was carried out in a packed column. The effects of mass fraction of water, SO2 inlet concentration, mixture gas flux and adsorbent dosage on the desulfurization efficiency of the adsorbent were studied. The optimal operations are decided as: mass fraction of water of 25%, inlet SO2 concentration of 0.15%, mixture gas flux of 300 L·h^-1 and adsorbent dosage of 30 g, and the adsorbent derived from sewage sludge was found to have obvious capability for the adsorption of SO2.