新型多胺羧甲基壳聚糖的合成及对Ni(Ⅱ)的吸附特性

Synthesis of carboxymethyl polyamines chitosan and its adsorption properties for Ni(Ⅱ)

为了提高壳聚糖(CS)吸附重金属的能力,对表面含有氨基乙酸基团的新型多胺羧甲基壳聚糖(CTGCS)进行了合成研究。其合成过程为:以CS为原料,通过戊二醛交联得到壳聚糖树脂(GCS),再经四乙烯五胺改性,得到多胺壳聚糖树脂(TGCS),最后采用一氯乙酸进行修饰,得到了目标产物(CTGCS)。通过对CS、GCS、TGCS和CTGCS进行红外光谱和XPS分析,对合成过程进行了分析。吸附结果表明,CTGCS对Ni2+的吸附规律符合Freundlich等温式模型,吸附过程符合拟二级动力学模型,最大平衡吸附量为533.8 mg·g-1,比TGCS的吸附量增加了1.5倍。

A novel amino acid functionalized polyamine carboxymethyl chitosan （CTGCS） was designed to improve adsorption ability of chitosan （CS） for heavy metals. Chitosan resin （GCS） was firstly obtainedvia cross-link reaction of chitosan and glutaraldehyde. After following modification by tetraethylenepentamine and chloroacetic acid, CTGCS was successfully synthesized. The samples at different reaction steps were characterized by using FTIR and XPS to understand reaction mechanism. Moreover, the adsorption ability of as-synthesized CTGCS for Ni2＋from aqueous solutions was investigated. The adsorption process conformed with the Freundlich isotherm model and could be fitted by the pseudo-second order kinetics model. The maximum adsorption capacity of CTGCS for Ni2＋was significantly improved up to 533.8 mg·g？1, about 1.5 times more than that of TGCS, indicating that CTGCS was a promising adsorbent for heavy metals.