木耳菌糠生物炭对阳离子染料的吸附性能研究

为了有效处理印染废水，以废弃木耳菌糠（AG）为原料，采用限氧热解法在350、550、750℃的温度下制备木耳菌糠生物炭（AGBC），处理含有孔雀石绿（MG）、番红花红T （ST）的有色废水.考察了不同初始pH值、吸附时间、初始浓度对AGBC吸附MG、ST的影响，讨论了吸附动力学及等温吸附特性.并利用傅里叶变换红外光谱（FTIR）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）等技术对吸附前后的菌糠生物炭进行表征，探究吸附机理.结果表明：随着热解温度的升高，吸附剂表面的含氧官能团数量逐渐减少，而比表面积和芳香化程度逐渐增加.MG的平衡吸附量随溶液pH值的升高而增大，而ST的平衡吸附量呈现相反趋势.AGBC对MG、ST的吸附分别在8h和4h基本达到平衡.AGBC对MG的吸附过程符合准一级动力学模型与Freundlich模型，说明吸附过程以物理吸附为主；对ST的吸附过程符合准二级动力学模型与Freundlich模型，说明吸附过程以化学吸附为主.与AG350和AG550相比，AG750对MG和ST的吸附量更高，经Langmuir模型拟合，其对MG和ST的最大吸附量分别为10249.79mg/g、3353.49mg/g.吸附机理表明，AGBC对MG的吸附主要为静电引力和π-π共轭作用，对ST的吸附主要为氢键作用、π-π共轭作用以及静电引力.说明AGBC对阳离子染料具有一定的吸附潜力，是一种经济高效的吸附材料.

Study on adsorption properties of biochar derived from spent Auricularia auricula substrate for cationic dyes.

In order to effectively treat dyeing wastewater and develop an economic and efficient adsorbent, the biochar derived from spent auricularia auricula substrate (AGBC) was prepared by oxygen limited pyrolysis method at 350℃, 550℃ and 750℃ to treat colored wastewater containing malachite green (MG) and safranine T (ST) in this study. The effects of initial pH, adsorption time and initial concentration on the adsorption of MG and ST by AGBC were investigated, and the adsorption kinetics and isothermal adsorption characteristics were discussed. FTIR, XRD and SEM and other techniques were used to characterize the biochar derived from spent auricularia auricula substrate before and after adsorption, and the adsorption mechanism was explored. The results showed that with the increase of pyrolysis temperature, the number of oxygen functional groups on the adsorbent surface decreased, while the specific surface area and aromatization degree increased gradually. The equilibrium adsorption capacity of MG increased with the increase of pH value, while the equilibrium adsorption amount of ST showed the opposite trend. The adsorption of MG and ST on AGBC reached equilibrium at 8h and 4h, respectively. The adsorption process of MG on AGBC followed the pseudo first order kinetics model and the Freundlich model, which indicated that it is mainly physical adsorption. The adsorption process of ST conformed to the pseudo second order kinetics model and the Freundlich model, which indicated that the adsorption process is mainly chemical adsorption. Compared with AG350and AG550, AG750had higher adsorption capacity for MG and ST, and the maximum adsorption capacity of AG750 on MG and ST were 10249.79mg/g and 3353.49mg/g, respectively, which were fitted by Langmuir model. The adsorption mechanism showed that the adsorption of MG on AGBC is mainly electrostatic attraction and π-π stacking interaction, while ST is mainly hydrogen bonding, π-π stacking interaction and electrostatic attraction. This showed that AGBC has excellent adsorption potential for cationic dyes, therefore it can be an economical and efficient adsorption material.