Abstract:

Based on the potential for sludge utilization and the high carbon content of biomass materials, using municipal sludge as the main raw material and dry mixing and impregnation as preparation method, a series of composite biochar were prepared by adding walnut shells, wheat straw, and bamboo powder as carbon enhancers. The influences of preparation methods and conditions on the adsorption performance of the prepared composite biochar were investigated. The results showed that the biochar prepared by impregnating and activating municipal sludge with 3 mol/L ZnCl₂ using walnut shell as a carbon under carbonization conditions at 400 ℃ had the best adsorption performance, with a specific surface area of 336.5 m²/g. The adsorption rate of methylene blue(MB) with an initial mass concentration of 50 mg/L could reach 99.47%, and the iodine value was 632 mg/g, reaching the iodine value standard of activated carbon for water treatment with moderate adsorption performance. The adsorption mechanism of MB by activated carbon was analyzed through adsorption kinetics and isothermal adsorption models. The results showed that the adsorption of MB by biochar was more in line with the pseudo-second-order reaction kinetics model and Langmuir isothermal adsorption model, and the adsorption process was mainly a single molecular layer adsorption dominated by chemical adsorption.

Key words: sludge, biomass, chemical activation, carbonization, adsorption

摘要：

基于污泥的资源化利用潜力和生物质材料含碳量高的特点，以市政污泥为主要原料，通过分别掺入核桃壳、小麦秸秆和竹粉作为增碳剂，采用干混和浸渍两种方式制备出一系列复合生物炭，考察了制备方法及制备条件对所制备复合生物炭吸附性能的影响。结果表明，以核桃壳为增碳剂，将市政污泥经3 mol/L ZnCl₂浸渍活化后于400 ℃炭化条件下制备得到的生物炭具有最佳吸附性能，其比表面积为336.5 m²/g，对初始质量浓度为50 mg/L的亚甲基蓝（MB）的吸附率可达到99.47%，碘吸附值为632 mg/g，达到中等吸附性能的水处理用活性炭碘吸附值标准。通过吸附动力学和等温吸附模型对吸附机理进行分析，结果表明，生物炭对MB的吸附更符合准二级反应动力学模型和Langmuir等温吸附模型，吸附过程为以化学吸附为主的单分子层吸附。

关键词: 污泥, 生物质, 化学活化, 炭化, 吸附

CLC Number: 

• X705