水热污泥渣活性炭的制备及其应用

利用城市污水厂剩余污泥经水热反应(T=320℃、P=12 MPa、RT=10 min)得到的污泥水热渣为原料,以ZnCl2为活化剂制备污泥水热活性炭。通过正交、单因素分析,研究制备工艺条件对污泥活性炭碘吸附性能及产率的影响。结合比表面积、孔径分布和浸出特性,对制备的污泥活性炭的性能进行评价,并探讨其作为水处理吸附剂的去除效果。结果表明当活化温度为450℃、活化时间为30 min、ZnCl2浓度为40%、固液比为1∶2时为最佳制备条件,制得的水热污泥活性炭的碘吸附值为543 mg/g、产率为56.0%。其比表面积为501.4 m2/g、平均孔径为5.78 nm、孔体积为0.47 mL/g、微孔体积为0.18 mL/g、中孔体积为0.21 mL/g,污泥中重金属大多被固化。将该产品用于处理ASBR出水,当吸附平衡时间约为90 min、投加量为11 g/mL时,COD的去除率为87%,吸附容量为76.82 mg/g。

Preparation and Application of Activated Carbon Made from Sludge-Based Hydrothermal Residues

Hydrothermal residues produced from excess sludge under the condition of 320 ℃,12 MPa and 10 min of reacting time were used to produce residue-based activated carbon,and zinc chloride(ZnCl2) was used as sludge activating agent.By orthogonal experiment and single factor analysis,the impacts of preparation conditions on the adsorption performance and mass yield of sludge activated carbon were studied.BET surface area,pore size distribution and leachability were analyzed to evaluate the performance of hydrothermal sludge-based activated carbon.The effects of hydrothermal sludge-based activated carbon on wastewater treatment were also studied.The result show that the optimum preparation conditions are as follows: activation temperature is 450 ℃,activation time is 30 min,concentration of ZnCl2 is 40 % and the ratio of solid and liquid is 1∶ 2.The iodine adsorption value by hydrothermal sludge-based activated carbon is 543 mg/g,mass yield is 56.0 % and BET surface area is 501.4 m2/g.Average pore diameter,total pore volume,micropore volume and mesopore volume are 5.78 nm,0.47 mL/g,0.18 mL/g and 0.21 mL/g,respectively.In addition,the heavy metals in the source sludge have been mostly solidified in the course of hydrothermal and pyrolytic process.When the amount of hydrothermal sludge-based activated carbon added is 11 g/L and the equilibrium adsorption time is about 90 min,the removal rate of COD is 87 % and the equilibrium adsorption capacity is 76.82 mg/g in ASBR treatment.