新型交联壳聚糖材料对地下水重金属Zn~(2+)的吸附性能

地下水重金属污染的原位修复技术研究日益受到关注.利用课题组研发的聚乙二醇(PEG400)作为交联剂合成的新型交联壳聚糖材料,用该新型材料吸附地下水中重金属Zn~(2+),探讨CTS:PEG比例和Zn~(2+)印迹量对吸附效果的影响,通过该材料对Zn~(2+)的吸附动力学、吸附等温线以及吸附热力学关系,讨论其吸附的内在机理.研究发现CTS:PEG=1:2和印迹的Zn~(2+)量是0.5%的交联壳聚糖,去除重金属Zn~(2+)的效率最高;其非平衡吸附遵循准二级动力学模型,吸附速率为0.1260mg·g~(-1)·h~(-1);在20℃,溶液pH值为7条件下,PEG-CTS对Zn~(2+)的最大吸附容量是18.20 mg·g~(-1),平均吸附能量是9.66kJ·mol~(-1);化学吸附为主,也包含物理吸附.

Absorption characteristics of bivalent zinc ion in groundwater absorbed by novel cross-linked chitosan material

In China, shallow groundwater has polluted by heavy metal pollution due to human activities. In situ groundwater remediation has been paid on attention by government and scientists. In this paper, the adsorption of heavy metal such as bivalent zinc ion(Zn~(2+)) in groundwater was studied by novel cross-linked chitosan material which was cross-linked with PEG400 and templated with bivalent zinc ion. The effect on removal efficiency made by the removal efficiency of CTS to PEG ratio and the amount of inprinted bivalent zinc ion was studied. Meanwhile, the kinetics, equilibrium and thermodynamics of the adsorptions processes were farther investigated. The result showed that under CTS:PEG=1:2, 5% bivalent zinc ion inprinted, the removal efficiency of bivalent zinc ion is the highest. The adsorption process of bivalent zinc ion follows the pseudo-second-order kinetic model. The adsorption rate reaches 0.1260 mg per gram per hour. Under temperature 20 ℃ and pH=7 conditions, the maximum adsorption capacity of bivalent zinc ion reaches 18.2 mg per gram according to the Langmuir adsorption isotherms and the average adsorption energy is 9.66 kJ per mole. The adsorption mechanism of bivalent zinc ion is predominant on the chemi-sorption process and also involved physical adsorption.