Preparation and adsorption properties of sludge composite biochar

Le résumé fourni par la source

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.

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