Study On Preparation Of Adsorbents Made From Sewage Sludges And Their Application

Adsorbents for wastewater treatment were prepared from biochemical and surplus sludge of sewage and surplus sludge of petrochemistry by chemical activation, and their physical and chemical properties were studied. The results show that the best performance of adsorbents are made by complex of ZnCl₂ and H₂SO₄, and the optimum preparation conditions are concentration of two activators 5 mol·L^-1, ratio of solid to liquid 1:2.5, pyrolysis temperature 550 ℃, pyrolysis time 2 h. Under the condition that the concentration is 0.5%, the removal rates of adsorbent made from the biochemical sludge for COD, total phosphorus and the chromaticity color of sewage are 63.2%, 98.3% and 87.5% respectively. On the condition that the flow is 20 mL·h^-1, the breakthrough time decreased from 12 h to 10 h by heating method for two times in dynamic adsorption experiment. Under the condition that the concentration is 0.05%, the oil removal rate of adsorbent made from the sludge of petrochemistry in the treatment of oil-bearing wastewater is 94.3%. The isothermal adsorption process can be described by Freundlich Model.Adsorbent for flue gas desulfurization was prepared from surplus sludge of sewage by pyrolysis, and its physical and chemical properties was studied. The results show that the optimum preparation conditions are particle diameter of material 0.1 cm ～0.5 cm, the flow of N₂ 30 L·h^-1, pyrolysis temperature 550 ℃, pyrolysis time 1 h. Under the adsorption conditions of inlet concentration of SO₂ 2021.38 mg·m^-3, O₂ 12%, flue gas velocity 4.25 m·min^-1, temperature 40℃, the desulfurization efficiency and adsorption capacity of sludge-derived adsorbent for simulation flue gas are 75.3% and 8.68 mg·g^-1 respectively, and those decrease to 66.2% and 6.25 mg·g^-1 after renovation by washing with water for two times. Under the adsorption conditions of inlet concentration of SO₂ 2021.38 mg·m^-3, O₂ 12%, H₂O (g) 12%, flue gas velocity 4.25 m·min^-1, temperature 60 ℃, the desulfurization efficiency and adsorption capacity are 85.1% and 12.20 mg·g^-1 respectively, and those decrease to 76.2% and 10.36 mg·g^-1 after renovation for two times. If water vapour is present, the adsorption mechanism of SO₂ is mainly changed from physical adsorption to chemical adsorption, and the adsorption effect of chemical adsorption is better than physical adsorption. Predictable values by stationary adsorption bed model and experimental values are tallied preferably.The adsorbents for flue gas desulfurization were prepared from surplus sludge of sewage by different modifation methods such as impregnation of Na₂CO₃ solution and...