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.