Preparation of Adsorbent of Flue Gas Desulfurization Made from Surplus Sludge of Sewage

Adsorbent for flue gas desulfurization was prepared from surplus sludge of sewage by modifation method of loading metal oxides, and its properties were studied by means of pore characteristics, SEM and elemental analysis. The adsorption mechanism of system of the adsorbent for SO2-O2-H2O(g)-N2 was studied by FTIR and thermal analysis. The results show that the performance of the adsorbent with loaded(mass fraction) both 5% MnO2 and 5% MgO is the best. The pore structure mainly consists of intermediate and large pores, the corresponding specific surface area is lower. Under the adsorption conditions of inlet concentration of SO2 2 021.38 mg/m3, mass fractions of O2 12% and H2O(g) 12%, flue gas velocity 2.13 m/min, temperature 60 ℃, the desulfurization efficiency and adsorption capacity of sludge-derived adsorbent are 93.7% and 99.3 mg/g respectively, and those decrease to 93% and 84.4 mg/g after renovation by washing twice with ammonia, indicating that the renovation effect is better. In the presence of water vapour, the synergistic action of the complex oxides accelerates the chemical adsorption of sludge-derived adsorbent for SO2. The isothermal adsorption process can be described by Freundlich Model, and the adsorption heat value is 78.4 kJ/mol. Predictable values via stationary adsorption bed model are in agreement with experimental values.