改性方法对辣木籽壳生物炭吸附亚甲基蓝的影响

The influence of modifying methods on the adsorption of methylene blue by Moringa oleifera seed shelling biochar

目的:探究不同工艺条件所制备的辣木籽壳生物炭对亚甲基蓝的吸附性能。方法:以辣木籽壳为原料,采用超声辅助碳酸钾—Fe_(3)O_(4)共浸渍热解和KOH浸渍—1000℃高温热解两种方法分别制备磁性辣木籽壳生物炭(Fe_(3)O_(4)-MOS)和改性辣木籽壳生物炭(KOH-MOS),并用XRD、SEM和FTIR对样品表面物化性质进行表征。在此基础上,通过平衡吸附法测定两种生物炭对溶液中亚甲基蓝(MB)的吸附特性,并用动力学、热力学和等温吸附模型分析对MB的吸附机理。结果:在试验所探究的条件下,Fe_(3)O_(4)-MOS和KOH-MOS对MB的吸附效率接近100%,且由Langmuir模型所得到最大吸附量分别为116.83,99.37 mg/g。结论:两种材料对MB的吸附是一个自发吸热熵增、化学吸附为主的过程。Fe_(3)O_(4)-MOS和KOH-MOS分别展现出了良好的磁分离能力和吸附能力。

Objective:The adsorption performance of the seed-shell biochar from Moringa oleifera prepared under different technological conditions on methylene blue was investigated in this study.Methods:The magnetic seed shelling biochar(Fe_(3)O_(4)-MOS) and modified seed shelling biochar(KOH-MOS)were prepared by ultrasonic-assisted K_(2)CO_(3)-Fe_(3)O_(4) co-impregnation pyrolysis and KOH impregnation pyrolysis at 1000℃,respectively.The physicochemical properties of the samples were characterized by XRD,SEM and FTIR.On this basis,the adsorption characteristics of the two kinds of biochar for methylene blue(MB)solution were determined by equilibrium adsorption method.Then the adsorption isotherm and kinetic model were used to fit the data to study the adsorption mechanism of biochar on MB.Results:It was found that under the experimental conditions,the adsorption efficiency of Fe_(3)O_(4)-MOS and KOH-MOS on MB was close to 100%,and the maximum adsorption capacity calculated by Langmuir model were 116.83 mg/g and 99.37 mg/g,respectively.Conclusion:The adsorption of MB by the two materials is a process of spontaneous endothermic entropy increase and chemical adsorption.Fe_(3)O_(4)-MOS showed good magnetic separation ability,while KOH-MOS showed good adsorption ability.