改性花生壳对苯酚的吸附

Adsorption of phenol by modified peanut shell

以花生壳为原料,使用环氧氯丙烷、二甲胺及吡啶,以N,N-二甲基甲酰胺为反应介质改性花生壳。结果表明:改性花生壳对苯酚的去除效果优于未改性花生壳。在实验条件下,吸附剂的吸附量在溶液pH为9,吸附时间为120 min时达到最大;溶液离子强度对吸附的影响较大。分析了该反应体系的动力学和热力学参数,改性花生壳吸附苯酚过程拟用准二级动力学模型处理,计算得出平衡吸附量与实验值相符。改性花生壳对苯酚的吸附符合Langmuir和Freundlich等温模式,R2均大于0.98,Qmax在84.49～108.76 mg/g之间,Freundlich模式的吸附强度n值在1.211～1.262之间,热力学参数△G、△H、△S表明改性花生壳对苯酚的吸附过程是自发、吸热过程。

The modified peanut shell was obtained using peanut shell,epichlorohydrin and dimethylamine in N,N-dimethylformamide solution.It is indicated that the modified peanut shell has higher adsorption capacity for phenol.The adsorption capacity of phenol is best under following conditions： pH 9 of aqueous solution and 120 min of contact time optimum.The ionic strength of aqueous solution is important role.This paper analyzes the kinetic and thermodynamic parameters of experimental data.The analysis of kinetic parameters shows that this adsorption procession fitts the pseudo-second order kinetic model and the equilibrium adsorption capacity measured is consistent with model calculation.The goodness of fit was justified by the Langmuir and Freundlich adsorption isotherms from the experimental data.The correlation coefficient（R2） was higher than 0.98.Maximum adsorption capacity（Qmax）was 84.49～108.76 mg/g.The n values of Freundlich isotherm were 1.211～1.262.The thermodynamics values of △G、△H and △S indicated this adsorption process is spontaneous and endothermic.