改性污泥活性炭对水中镉离子的吸附性能

Adsorption of Cd(Ⅱ) from aqueous solution by modified activated carbon made from activated sludge

以城市污水处理厂的剩余污泥为原料,氯化锌为活化剂制备污泥活性炭,对一部分污泥活性炭用6.0 mol/L的硝酸进行改性,并研究了未改性和改性的污泥活性炭对Cd2+的吸附行为的影响。结果表明,在pH为5.0、Cd2+初始浓度为100 mg/L、吸附剂投加量为2.0 g/L、反应温度为25℃时,未改性的污泥活性炭吸附容量为8.45 mg/g,硝酸改性的污泥活性炭吸附容量达到了23.35 mg/g。改性和未改性的污泥活性炭对Cd2+都有较好的吸附容量,硝酸改性大幅度提高了污泥活性炭对Cd2+的吸附性能。常温下改性污泥活性炭对Cd2+的吸附符合Langmuir吸附等温式。

Activated carbon was prepared from excessive sludge from municipal wastewater treatment plant,and zinc chloride was used as the activation reagent.The activated carbon from sludge was also treated using 6.0 mol/L nitric acid to prepare modified activated carbon.The performances of the two types of activated carbon for Cd2＋ adsorption were compared.Results show that the adsorption capacity of the unmodified activated carbon and modified activated carbon was 8.45 and 23.35 mg of Cd2＋ per g of activated carbon,respectively at a pH of 5.0,an initial concentration of Cd2＋ of 100 mg/L,and a dosage of activated carbon of 2.0 g/L.Therefore,these two types of activated carbon had good adsorption capacities,and the modification by nitric acid greatly improved the adsorption performance for Cd2＋.At room temperature,the adsorption of Cd2＋ by the modified sludge activated carbon accords with the Langmuir equation pretty well.