Study On Sludge Adsorbent Preparation And Its Adsorption Performance Of H₂S

With the improvement of sewage treatment capacity in municipal sewage treatmentplant, the disposal of sewage sludge has aroused people’s concern in recent yearsincreasingly. The limitation of the traditional sludge disposal methods is increasinglyprominent. Using sewage sludge to prepare sludge adsorbent is a new method for theresource, which can be applied to the H₂S removal, in order to realize the resourcerecovery and the purpose of using waste treat waste.This paper used excess sludge of municipal wastewater treatment plant as rawmaterial to prepare sludge adsorbent in chemical activation method, screened theactivator species and studied the influence factors of sludge adsorbent preparation,including activator concentration, solid-liquid ratio, carbonization temperature andcarbonization time. Results indicate that the optimal conditions are4mol/L ZnCl2immersed, sludge pyrolyzed at550°C for60min in a solid-liquid ratio of1.5. Themaximal iodine value of sludge adsorbent is599.32mg/g, and the maximal methyleneblue value is236.74mg/g.To improve the desulfurization performance of sludge adsorbent, this paper usedrare earth element cerium to prepare modified sludge adsorbent, and discussed theoptimum technological conditions. Results show that the maximal H₂S adsorptionthrough time of sludge adsorbent with cerium doped is171min under the optimumtechnological conditions that carbonization temperature is650°C, dipping time is15h,carbonization time is2h and cerium doped quality is5%; the maximal H₂S adsorptionthrough time of sludge adsorbent with cerium loaded is183min under the optimumtechnological conditions that calcination temperature is750°C, cerium loaded quality is3%, calcination time is1.5h and dipping time is6h, the H₂S adsorption through time ofunmodified sludge adsorbent is47min.This paper analyzed and characterized sludge adsorbent through the specificsurface area and pore structure analysis, SEM,XRD, TG-DTG, FI-IR and XPS.Analysis shows that the sludge adsorbent has high specific surface area and abundantpore structure, the surface oxygen-containing functional groups benefits the H₂Sremoval.Sludge adsorbent removes H₂S through physical adsorption and chemicaladsorption. Cerium modified sludge adsorbent has greater chemical adsorption. Thebetter oxidation properties of CeO₂promotes the oxidation of H₂S. In addition, themetal oxides on the surface of the sludge adsorbent are the active sites of the H₂Sadsorption. Cerium decentralizes these metal oxides on the surface of the sludgeadsorbent, which is conducive to the removal of H₂S.