豆秸秆基多孔炭的制备及其对亚甲基蓝染料吸附行为的研究

Preparation and adsorption behavior study of soybean stalks-based porous carbon for methylene blue dyes

为实现农林废弃物豆秸秆最大价值化利用且有效应用于亚甲基蓝染料废水的吸附,以农林废弃物豆秸秆为原料,采用碱活化炭化-酸刻蚀结合法制备出多孔炭SSC-800。利用拉曼光谱,X射线衍射仪(XRD)和氮气的吸附/脱附对豆秸秆基多孔炭SSC-800进行性能分析,研究了多孔炭SSC-800添加量和溶液pH对吸附效果的影响并剖析炭材料对亚甲基蓝染料的等温吸附模型和动力学模型。结果表明:当原料与活化剂比例仅为1∶2时,制备的SSC-800其比表面积达到2101.28 m^(2)/g,其中微孔比表面积为1753.19 m^(2)/g。对亚甲基蓝染料的去除率高达99.6%,最大吸附量可达到1369.08 mg/g;多孔炭SSC-800对亚甲基蓝染料的吸附符合Langmuir吸附等温模型,属于单分子吸附类型,吸附动力学符合准二级动力学,以化学吸附为主。

In order to realize the most valuable utilization of agricultural and forestry waste soybean stalks for methylene blue dye wastewater adsorption,the porous carbon SSC-800 was prepared from soybean straw by coupling alkali activated carbonization and acid etching method.The Raman spectroscopy,X-ray diffraction(XRD),and N_(2) adsorption/desorption,were characterized on the performance of soybean stalks-based porous carbon SSC-800,the effects of the dosage of adsorption,and pH of the solution on the adsorption were tested,and the isothermal adsorption model and dynamics of carbon materials on methylene blue dyes were further analyzed.The results show the specific surface area of the prepared SSC-800 could reaches to 2101.28 m^(2)/g when the ratio of raw material to activator is only 1∶2,in which the micropore ratio surface area is 1753.19 m^(2)/g.The removal rate of methylene blue could reach to 99.6%,and the maximum adsorption capacity is 1369.08 mg/g.The adsorption of methylene blue is in line with the Langmuir model,and belongs to the type of monolayer molecule sorption.The adsorption kinetics conforms to the pseudo-second-order model and which is dominated by chemical adsorption.