双功能基聚倍半硅氧烷的合成及其对Hg^(2+)和Ag^(+)的吸附性能研究

Synthesis of Bifunctional Polysilsesquioxane and Its Adsorption Property for Hg^(2+) and Ag^(+)

本文采用溶胶凝胶法,通过酸催化水解、碱催化缩合合成了含氮、硫双功能基的聚倍半硅氧烷(ASPSS),研究了其对Hg^(2+)和Ag^(+)的吸附性能;并探究了溶液pH值、时间、温度、金属离子初始浓度等因素对吸附性能的影响。结果表明:ASPSS对Hg^(2+)和Ag^(+)均表现出良好的吸附性能,在pH值为6时吸附性能最佳;对Hg^(2+)和Ag^(+)的吸附分别在360 min和270 min达到平衡,动力学吸附过程符合拟二级动力学模型且液膜扩散为控速步骤;等温吸附数据表明,ASPSS对两种金属离子的吸附量随温度和金属离子浓度的增大而增大,吸附过程符合Langmuir模型,为单分子层吸附;热力学参数表明,ASPSS对两种金属离子的吸附过程均为自发进行的、吸热、熵增的过程。本研究为水体中Hg^(2+)和Ag^(+)的高效脱除提供了一种高效吸附剂,在滨海生态环境保护领域具有潜在应用价值。

In this paper,bifunctional polysesquioxane microspheres(ASPSS) that contain nitrogen and sulfur were synthesized by sol-gel method via acid-catalyzed hydrolysis and alkali-catalyzed condensation process.The adsorption performance of ASPSS for Hg^(2+) and Ag^(+) was systematically investigated.The effects of pH value,time,temperature and initial concentration of metal ions on the adsorption property were investigated.Results showed that ASPSS exhibited good adsorption performance for both Hg^(2+) and Ag^(+).The optimal pH for the adsorption of Hg^(2+) and Ag^(+) was 6.Adsorption kinetic indicated the adsorption for Hg^(2+) and Ag^(+) could reach equilibrium at 360 min and 270 min.Adsorption kinetic could be well fitted by pseudo-second-order(PSO) models with film diffusion as rate-controlling stage.Adsorption isotherm values demonstrated the adsorption capacity could be increased by raising initial concentration of the metal ions and temperature.The adsorption process could be described by Langmuir model with monolayer adsorption behavior.Thermodynamic parameters suggested the adsorption was a spontaneous,endothermic and entropy increased process.The research work provided efficient adsorbents for the removal of Hg^(2+) and Ag^(+) from aqueous system,which shows great potential in coastal ecological environment protection.