胺化木质素对水中硝基苯吸附性能的研究

Adsorption of nitrobenzene from aqueous solution by aminated lignin

含硝基苯的工业废水对环境造成了严重的污染。本文用环氧氯丙烷、乙二胺对碱木质素进行改性制备胺化木质素,详细研究了溶液pH、接触时间、温度、浓度等因素对胺化木质素吸附水溶液中硝基苯性能的影响。结果表明:溶液pH对吸附有较大的影响,吸附的最佳pH为8,胺化木质素对硝基苯吸附3 h后达到平衡,与准一级吸附动力学模型有较好的拟合;吸附容量随着浓度增大而增大,平衡吸附量可达到33.8 mg/g,等温吸附符合Freundlich方程;随着温度的升高,吸附量逐渐增大,吸附焓变(ΔH)为6.17 kJ/mol,表明该过程为吸热过程。

The nitrobenzene in industrial wastewaters has caused many serious environmental problems.In this work,aminated alkali lignin using epichlorohydrin and ethylenediamine was prepared for the adsorption removal of nitrobenzene.The adsorption performance of this novel adsorbent to nitrobenzene was investigated considering the effect of initial pH,contact time,initial nitrobenzene concentration and temperature.The results indicated that pH plays a key role in nitrobenzene adsorption capacity and the optimal pH was found to be 8.The adsorption equilibrium can be achieved in 200 min and the adsorption kinetics is well described by pseudo-first-order model.The adsorption capacities increased with the increase of initial nitrobenzene concentration and the saturated adsorption capacities reach 33.8 mg/g at pH 8.0.It was found that the equilibrium data can be described by the Freundlich equation,and the adsorption capacity increased with the increase of temperature.Enthalpy change（ΔH）was found to be 6.17 kJ/mol which indicated that the adsorption of nitrobenzene on the aminated alkali lignin is an endothermic process.