壳聚糖交联β-环糊精聚合物对Cu^2+的吸附研究

Adsorption of Cu^2+by chitosan corss-linkedβ-cyclodextrin polymers

为了提高壳聚糖对金属离子的吸附能力,利用柠檬酸作为交联剂,通过溶液聚合的方法将原材料壳聚糖和β-环糊精交联制成壳聚糖/β-环糊精聚合物。通过扫描电镜和红外光谱对两者结构进行表征,并用来吸附溶液中Cu^2+,考察了溶液pH值、吸附时间、Cu^2+初始浓度以及温度对吸附Cu^2+过程的影响。结果表明:柠檬酸的羧基分别与β-环糊精的羟基(—OH)和壳聚糖的羟基(—OH)反应将两者交联,其产物拥有更多的吸附位点和更大的比表面积;在pH值为6,吸附温度为30℃,吸附时间为40 min,Cu^2+初始质量浓度为500 mg/L的条件下吸附效果最佳,最大吸附量为141.90 mg/g;该吸附过程更适合于用拟二级动力学模型和Langmuir等温模型来描述。

In order to improve the adsorption capability of chitosan to metal ions,using citric acid as a cross-linking agent,the raw material chitosan andβ-cyclodextrin polymers were cross-linked to make chitosan/β-cyclodextrin polymers by solution polymerization.The structure of chitosan andβ-cyclodextrin were characterized by scanning and infrared spectroscopy,and then,they were used to adsorb Cu^2+from solution.The effect of solution pH value,adsorption time,initial concentration of Cu^2+and temperature on Cu^2+adsorption,were investigated.The results showed that,the carboxyl of citric acid was linked to hydroxyl(—OH)ofβ-cyclodextrin and chitosan respectively through the reaction,the product had more adsorption sites and larger specific surface area.The best adsorption effect was obtained under the condition that the pH value was 6,the adsorption temperature was 30℃,the adsorption time was 40 min,the initial mass concentration of Cu^2+was 500 mg/L,the maximum adsorption quantity was 141.90 mg/g.The adsorption process is more suitable to be characterized by pseudo-second order kinietic model and Langmuir isothermal model.