荸荠皮渣改性产物作为重金属吸附剂的研究

Characterization of Modified Peel Dreg Cellulose of Chinese Water Chestnut as Heavy Metal Ion Sorption Agent

摘要:

荸荠皮渣经过预处理后进行改性：在吡啶试剂回流的情况下与琥珀酸酐反应，以引入羧基官能团。得到的改性荸荠皮渣进行重金属吸附，分别就金属离子初始浓度、pH和吸附时间进行吸附过程的研究。并对改性荸荠皮渣的吸附特性与机理进行了初步研究与探讨。结果表明：改性荸荠皮渣（MWCP）对三种重金属离子（Cu2+、Pb2+、Cd2+）具有显著的吸附作用，400 mg/L浓度下，吸附4 h基本达到吸附平衡：Cu2+、Pb2+、Cd2+分别达到44.80±2.68 mg/g、80.73±6.25 mg/g、45.94±3.15 mg/g；Cu2+、Pb2+、Cd2+的最佳pH分别为5.5、5.6和7.8；吸附过程是一种化学吸附过程，对吸附动力学的拟合较为符合拉格朗日假二级拟合模型；吸附等温模型比较符合langmuir等温吸附；红外图谱的相关吸收峰的变化说明荸荠皮渣发生了羧基化改性反应。

Abstract:

In this research, carboxylic functional group was introduced into the fibre backbone of peel dreg of Chinese water chestnut by succinic anhydride modification in pyridine. The adsorption capability of the modified peel dreg on Cu2+, Cd2+ and Pb2+ was influenced by the initial metal concentration, adsorption time and solution pH value. The maximum adsorption capacities of modified peel dreg of Chinese water chestnut reached 44.80±2.68 mg/g for Cu2+ at pH 5.5, 80.73±6.25 mg/g for Pb2+ at pH 5.6 and 45.94±3.15 mg/g for Cd2+ at pH 7.8. As an chemical style, the kinetics of adsorption process was accorded with lagrange pseudo second-order model. The adsorption isothermal experimental data coincided well with Langmuir model. FT-IR analysis indicated that the carboxylation reaction took place during the modification of the Chinese water chestnut peel.