共存物质对重金属絮凝剂MCC除镉性能的影响

Effects of coexisting substances on cadmiun removal performance by heavy metal flocculant MCC

为进一步拓展天然高分子絮凝剂壳聚糖的应用范围,以壳聚糖、L-半胱氨酸为原料,通过酰胺化反应制备一种具有重金属捕集功能的高分子重金属絮凝剂-2-氨基-3-巯基丙酰壳聚糖(MCC),研究了水体中常见的阴阳离子、有机配位剂及浊度对MCC除镉性能的影响,探讨了絮体形貌与絮体分形维数及絮凝除镉效果间的关系。结果表明,Na+、Cl-、NO-3、F-、SO2-4的存在对MCC除Cd2+均有促进作用,Ca2+表现为明显的抑制作用;低浓度的EDTA对除镉有促进作用,随着EDTA浓度的增大,逐渐转为抑制作用;低浓度的腐殖酸对MCC去除Cd2+有显著的促进作用;在一定范围内,浊度可促进MCC对Cd2+的去除;絮体间空隙越多,絮体分形维数越小,除镉效果越好。

In order to extend the application range of natural polymer flocculant chitosan, a macroinolecular heavy metal floeeulant-2-amino-3-mercapto-propionyl chitosan（MCC） which traps heavy metals was prepared by amidization reaction with chitosan and L-eysteine. Several coexist ions, ligand agents and turbidity which affect the removal rate of Cd2 ＋ were studied. The relationships among the morphology of floes, the fractal dimension of floc and the effect on removal rate of cadmium were discussed. The results show that the present of Na＋ , Cl- , NO3- , F- ,SO24- and humic acid improve the removal rate of Cd2 ＋ Turbidity and low concentration of humie acid can promote the removal rate of Cd2＋ either. Low concentrations of EDTA promote the removal rate of cadmium, but along with the increasing concentration of EDTA, it turns into inhibition. The more the interstices between flocs and the less the fraetal dimension of flocs, the better removal efficiency of cadmium ions.