多孔壳聚糖复合吸附材料的制备及应用

Preparation of porous chitosan composite adsorbents and application in adsorption of heavy metal ions

以柠檬酸改性的β-环糊精(CA-CD)和壳聚糖(CS)为原料,采用溶胶-凝胶法制备了柠檬酸改性β-环糊精交联的壳聚糖吸附材料(CA-CD/CS),用FTIR、SEM、TG对CA-CD/CS进行表征,并研究了CA-CD/CS对重金属离子Pb2+、Cu2+、Cd2+的吸附行为。结果表明,CA-CD已通过酰胺键成功和壳聚糖分子发生交联,CA-CD/CS具有一定孔隙结构,其热分解温度略低于CS。静态吸附结果表明,在25℃、p H=6时,CA-CD/CS对Pb2+、Cu2+、Cd2+饱和吸附量分别为85. 5,71. 2,22. 2 mg/g。CA-CD/CS对混合金属离子的吸附选择性与单一组分金属离子一致。吸附饱和的CA-CD/CS经2%的稀硝酸溶液洗脱后,循环使用6次,饱和吸附量几乎不下降。

Citric acid modifiedβ-cyclodextrin crosslinking chitosan(CA-CD/CS)was prepared using citric acid modifiedβ-cyclodextrin(CA-CD)and chitosan(CS)as raw materials.The adsorption of CA-CD/CS for heavy metal ions Pb^2+,Cu^2+and Cd^2+was studied.The chemical composition,morphology,and thermal stability of the CA-CD/CS sponge were characterized by FTIR,SEM,and TG analysis respectively.The adsorption kinetics and the effects of pH on adsorption were investigated using a static adsorption method.The selectivity in treating mixed-ion solution and the reusability of the CA-CD/CS sponge were also investigated.The maximum adsorptions of CA-CD/CS for Pb^2+,Cu^2+and Cd^2+at 25℃,pH=6 were determined to be 85.5,71.2,22.2 mg/g,respectively.The adsorption selectivity for metal ion mixture agreed with the trend in maximum adsorption.The adsorbed metal ions could be convenient desorbed by adjusting pH,allowing the sponge to be reused.The result showed that the adsorption capacity of CA-CD/CS remained high after 6 cycles.