生物质活性炭的制备及其染料废水中的应用

Preparation of activated carbon from activated sludge and its application in treating dye wastewater

以城市污水厂活性污泥为原料,用3 mol/L ZnCl2溶液活化,通入水蒸气作活化气制备活性炭吸附剂。实验结果表明,温度为600℃条件下,活化时间为1 h,制得的活性炭其碘吸附值为374.10 mg/g,比表面积为381.62 m2/g,孔容积为0.25 cm3/g,微孔容积为0.11 cm3/g。并进一步将生物质活性炭应用于染料废水的处理,考察了吸附时间、活性炭投加量和pH对色度及TOC的脱除效果的影响。室温下,酸性大红GR染料废水初始浓度为300 mg/L,污泥活性炭的最佳投加量为2%(质量分数),吸附15min,废水色度脱除率可达99.6%,TOC去除率可达99.7%,利用等温吸附实验作吸附等温线,吸附等温线可以用Freundlich或Langmuir方程描述。

An activated sludge sample from a local sewage treatment plant was first dried at 105℃ and ground （1-2 mm） and then soaked in 3 mol/L ZnCl2 solution for 24 h; the centrifuged cake was dried and steam activated at 600 ℃ for 1 h, and the product was washed to remove the ZnCl2 and other inorganic impurities and finally dried again to result in the activated carbon. The activated carbon exhibited an iodine capacity of 374.1 mg/g, a BET surface area of 381.62 m^2/g and pore volume of 0.25 cm^3/g and a micropore volume of 0.11 cm^3/g. The capacities of this carbon for color and TOC of a simulated dye wastewater were well represented by both the Freundlich and the Langmuir adsorption isotherm models; higher capacities were obtained at a neutral pH. The activated carbon prepared from sewage treatment plant activated sludge may be attractive for treating dye wastewater.