摘要
利用反相悬浮分散法和聚乙二胺改性制备成Fe_3O_4/壳聚糖磁性微球(PEMCS)以提高其氨基含量。采用X射线衍射(XRD)、红外(IR)、热重分析(TGA)等对其进行了表征,考察PEMCS对Hg^(2+)和UO_2^(2+)的吸附性能。结果表明,其吸附剂粒径小(15—30μm),吸附速率快;当氨基含量6.47mmol/g、pH<3时可选择性分离Hg^(2+)和UO_2^(2+),因Hg^(2+)能与Cl-形成络阴离子(HgCl_3^-),以离子交换机理吸附,而UO_2^(2+)则不能。对Hg^(2+)与UO_2^(2+)的饱和吸附容量q_m(mmol/g)分别为2.19与1.38。动力学数据采用Lagergrent拟合,对Hg2+与UO_2^(2+)的吸附速率常数k_(ad)(min^(-1))分别为0.087和0.055。UO_2^(2+)和Hg^(2+)可用1mol/LH_2SO_4脱附,UO_2^(2+)还可用2mol/LHCl脱附,脱附率>90%。
Fe3O4/chitosan magnetic microspheres were prepared with inverse-phase suspension dispersion method. It was modified through the reaction with poly（ethyleneimine） to increase the content of amine group of the adsorbent. The samples were characterized by X-ray diffraction （XRD）, FT-IR, and thermogravimetric analysis （TGA）. Adsorption performance of the modified chitosan microspheres toward Hg^2＋ and UO2^2＋ was investigated. The results showed that the concentration of amine group of the adsorbent was 6.47 mmol/g. The adsorption rate was fast due to their small size （15-30μm）. Selective separation of Hg^2＋ and UO2^2＋ was achieved at pH〈3.This was due to the fact that Hg^2＋ was able to form complexing anion （HgCl3） with Cl^- and adsorb onto the modified chitosan adsorbent through ion-exchange mechanism, but UO2^2＋ could not. The maximum adsorption capacity （qm） was 2.19 mmol/g for Hg^2＋ and 1.38 mmol/g for UO2^2＋. The adsorption rate constant calculated by Lagergrent equation was 0.087 min^-1 for Hg^2＋, 0.055 min^-1 for UO2^2＋. More than 90% desorption efficiency for UO2^2＋ and Hg^2＋ was achieved using 1 mol/L H2SO4 and for UO2^2＋ using 2 mol/L HCl.
出处
《核技术》
EI
CAS
CSCD
北大核心
2007年第9期768-772,共5页
Nuclear Techniques
基金
东华理工学院核资源与环境工程技术中心开放测试基金(070710)
国家留学基金委资助(22307S05)
