Purification of Low-Concentration Carbonyl Sulfide by Red Mud-Based Adsorbent

Bauxite residue, also known as red mud (RM), is a kind of industrial solid waste with high alkali content, complex composition and difficult utilization. In this study, a new type of RM-based adsorbent was prepared by using polyethylene glycol modified RM and was used to remove low concentration of COS in flue gas. The optimum preparation conditions of adsorbent and the optimum technological parameters of COS adsorption purification were investigated. Under the optimal conditions, the adsorption efficiency of the new adsorbent exceeds 95%, and the COS adsorption capacity reaches 63.56 mg/m³. The characterization results showed that the main active components of the adsorbent were active alkali, FeOOH and Fe₃O₄, and the main products were Na₂S₂O₃, Na₂SO₄, FeS and FeS₂.