甲壳素/聚乙烯亚胺复合物对水溶液中Cr(Ⅵ)的吸附

Chitin/polyethyleneimine composite as an adsorbent of aqueous Cr(Ⅵ)

均相条件下,通过环氧氯丙烷将聚乙烯亚胺(PEI)接枝于甲壳素(CT)分子上,制备CT基Cr(Ⅵ)生物吸附剂(CTP)。采用FT-IR、XRD、SEM、EDS和Zeta电位表征CTP的结构与形貌。考察了溶液的p H、吸附时间、Cr(Ⅵ)的初始浓度、处理温度和共存离子对吸附的影响。结果表明,PEI与CT质量比为4:1的条件下所制备的CTP4,在p H为2.0和温度为25℃的条件下,根据Langmuir模型计算的最大吸附量为330.4 mg·g–1;吸附过程经过约60 min达到平衡,符合准二级动力学模型,是一个自发、吸热的过程;CTP4可重复使用,经过6次吸附-解吸循环后,其吸附量保持初次吸附量的89.5%。

The polyethyleneimine（PEI） was homogeneously grafted onto the chitin（CT） with aid of epichlorohydrin to produce CT-based biosorbents（CTP） for removal of Cr（Ⅵ） from water. The structure and morphology of CTP were characterized by FT-IR, XRD, SEM, EDS and Zeta potential. The effects of p H value, contact time, initial Cr（Ⅵ） concentration, treatment temperature and coexisting ions on the Cr（Ⅵ） adsorption were investigated. The results showed that the CTP with a mass ratio of PEI：CT = 4：1（CTP4） presented a maximum adsorption capacity of 330.4 mg·g–1 according to the Langmuir isotherm at 25℃ and p H value 2.0. The adsorption was a spontaneous and endothermal process, which achieved the equilibrium within 60 min and followed the pseudo-second-order kinetic model. After six cycles of adsorption-desorption, the CTP4 remained 89.5% of its original adsorption capacity, suggesting its favorable reusability.