硫杂冠醚为载体的液膜中Ag(I)的迁移研究

Transfer of Ag(I) through the liquid membrane with thiacrown as carrier

选择内耦合液膜技术,以CHCl3为膜溶剂,1,4,7,10,13,16-六硫杂-18冠-6(HT18C6)为流动载体,研究Ag(I)在(HT18C6-CHCl3)液膜体系中的迁移过程.考察了载体的种类和浓度、料液相浓度、接受相的种类、浓度和pH值、搅拌速度以及温度等因素对Ag(I)离子迁移过程的影响.结果表明,在最佳迁移条件下:载体浓度为5.0×10-4mol/L、料液相NaClO4浓度为5.0×10-3mol/L、接受相Na2S2O3浓度为0.05mol/L、搅拌速度为120r/min、工作温度控制在293～313K范围内,Ag(I)的迁移率可达到99%以上.同时Hg(Ⅱ),Mg(Ⅱ),Ca(Ⅱ),Ni(Ⅱ),K(I),Na(I),Cr(Ⅲ),Zn(Ⅱ),Cu(Ⅱ),Pb(Ⅱ)和Cd(Ⅱ)等共存金属离子对Ag(I)的迁移无影响.对废定影液样品中Ag(I)进行迁移富集,银的回收率在99.3%～99.8%.

The transport of silver（I） ion through a chloroform bulk liquid membrane containing hexathia- 18- crown-6（HT18C6） as a carrier was studied. Factors, such as varieties and concentrations of thiacrown ethers in the membrane, silver（Ⅰ） concentration of feed phase, pHs of receiving phase, temperature and rate of stirring, were optimized. The results showed that transport rate of silver（Ⅰ） was over 98% when the carrier concentration in the membrane was 5.0×10^-4mol/L, NaClO4 concentration in feed phase was 5.0 ×10^-3 mol/L, concentration of receiving phase was 5.0×10^-3 mol/L, stirring rate 120 was r/min and working temperature was 293-313 K, respectively. The selectivitv of Ag＋ transport from the aoueous solutions containing nthor metal cations such as Hg^2＋ , Mg2＋, Ca^2＋, Ni^2＋ , K^＋, Na^＋, Cr^3＋ ,Zn^2＋, Cu^2＋ , Pb^2＋ and Cd^2＋ ions was investigated. However, no interference was found among these cations. Recovery rate of 99.3 % -99.8 % was obtained when the membrane was applied to collect the silver （Ⅰ） in the photographic developing waste.