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为了提高壳聚糖对重金属离子的吸附性,以壳聚糖(CS)为基体,1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC.HCl)为缩合剂,N-羟基-丁二酰亚胺(NHS)为偶联剂,将L-精氨酸接枝到CS大分子上,制备出L-精氨酸接枝壳聚糖CS-L-Arginine(CA),并通过3因子3水平正交实验筛选出最优工艺。通过红外光谱(FT-IR)、扫描电镜(SEM)表征了产物的结构组成和表观状态。采用坂口反应测定了产物的接枝率(GR)。结果表明,当反应物的摩尔比为n CS:n Arg:n EDC=1:1:1,n EDC:n NHS=1:1,反应时间为12h,体系p H=5.5时,接枝率(GR)可达17.05%。吸附试验结果显示,在p H=6、温度25℃条件下,CA(GR=17.05%)对浓度25g/L的Cu~(2+)、Ni~(2+)的去除率分别达到75.36%和68.42%,吸附符合准二级动力学模型,吸附过程符合Langmuir等温吸附模型,也基本符合Freundlich等温吸附模型。
In order to improve the adsorption of chitosan to heavy metal ions, chitosan (CS) as a matrix, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC.HCl) L-arginine grafted chitosan CS-L was prepared by grafting L-arginine onto the CS macromolecule as a condensing agent and N-hydroxy-succinimide (NHS) as a coupling agent -Arginine (CA), and the optimal process was screened by 3-factor 3 level orthogonal experiment. The structure and apparent state of the product were characterized by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The grafting rate (GR) of the product was determined by the Sakaguchi reaction. The results showed that when the reactants molar ratio n CS: n Arg: n EDC = 1: 1: 1, n EDC: n NHS = 1: 1, the reaction time was 12h and the system was p H = 5.5, (GR) up to 17.05%. The results of adsorption experiments showed that the removal rates of Cu 2+ and Ni 2+ with the concentration of 25g / L were 75.36% for CA (GR = 17.05%) at pH 6 and 25 ℃, respectively. And 68.42% respectively. The adsorption was in accordance with the quasi-second-order kinetic model. The adsorption process accorded with the Langmuir isothermal adsorption model and the Freundlich isothermal adsorption model.