用于吸附养殖尾水中Cu^(2+)的温度敏感型淀粉基水凝胶制备及性能分析

Preparation and application in removal of Cu^(2+) from aquaculture tailwater for thermoresponsive starch ether/carboxymethyl starch composite hydrogel

为了快速移除水产养殖尾水中的铜离子(Cu^(2+)),合成了一种新型温度敏感多糖基水凝胶,以具有结构和性能优势的2-羟基-3-异丙氧基丙基淀粉醚(HIPS)和羧甲基淀粉钠(CMS)为原料,以乙二醇二缩水甘油醚(EDGE)和CaCl 2为交联剂,通过形成共价键和离子键的混合交联方式制备具有温度敏感性能的HIPS/CMS复合凝胶,利用傅里叶转换红外光谱(FT-IR)、扫描电镜(SEM)对复合凝胶的结构和内部形貌进行表征,研究复合凝胶的温度敏感性能,并探究了复合凝胶对水产养殖尾水中Cu^(2+)的吸附效果。结果表明:HIPS/CMS复合凝胶具有优异的温度敏感性能,当温度高于其体积相转变温度(VPTT,34.1℃)时,复合凝胶体积明显收缩,溶胀率从62.1倍下降至33.6倍;HIPS/CMS复合凝胶对水产养殖尾水中Cu^(2+)具有良好的吸附性能,最大吸附量可达25.2 mg/g;复合凝胶对Cu^(2+)吸附过程符合Langmuir吸附模型,属于单分子层化学吸附;利用该复合凝胶的温度敏感性能,可实现HIPS/CMS复合凝胶的回收再利用,并且经5次吸附-解吸循环后吸附量仍可达15.1 mg/g。研究表明,本研究制备的HIPS/CMS复合凝胶对养殖尾水中的Cu^(2+)的去除效果较好且绿色环保,可以重复使用。

A thermoresponsive hydrogel composed of 2-hydroxy-3-isopropoxypropyl starch(HIPS)and carboxymethyl starch sodium(CMS)was synthesized via cross-linking with hybrid crosslinkers including ethylene glycol diglycidyl ether(EDCE)and calcium chloride(CaCl 2)for removal of copper ions from aquaculture tailwater.The internal structure,morphology and thermoresponsive performance of the hydrogels were characterized by Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM).The adsorption behavior of HIPS/CMS composite hydrogel for Cu^(2+)in aquaculture tailwater was explored under different adsorption capacities of Cu^(2+),pH,and Cu^(2+)concentrations.The results showed that the HIPS/CMS hydrogel had excellent thermoresponsive performance,with the significantly shrunken volume at temperature of higher than its volume phase transition temperature(VPTT,34.1℃),and decrease in the swelling rate from 62.1 times to 33.6 times.HIPS/CMS hydrogel has desirable adsorption properties for Cu^(2+)in aquaculture tailwater,with the maximal adsorption capacity of 25.2 mg/g.The adsorption process of Cu^(2+)was conformed to the Langmuir model.The thermoresponsive of the hydrogel was used to realize the recovery and reuse of HIPS/CMS hydrogel,with the Cu^(2+)adsorption capacity of 15.1 mg/g after five adsorption-desorption cycles.The findings indicated that the HIPS/CMS composite gel prepared in this study had a good effect on the removal of Cu^(2+)and was friendly reused for environment.