Preparation And Performance Of Adsorption Material With Recognition Selectivity Towards AuCl₄^-

Gold performs excellent physical and chemical properties,and has extensive industrial applications and high market price.But scarcity and high value of gold make its efficient recovery receiving a great deal of attention.Through molecular design,three adsorption materials,LS-g-PDMAEMA,D301-g-PDMC and D301-g-IIPDMC,were designed and prepared.Their adsorption properties,recognition selectivity and reusability of AuCl₄^-were studied.The grafting material LS-g-PDMAEMA was obtained by grafting the functional monomer dimethylaminoethyl methacrylate?DMAEMA?onto the surface of LS resin via the method of surface initiated graft polymerization,then the quaternary transformation was took place to obtaintheadsorbentLS-g-QPDMAEMA.Intheprocessofpreparationof LS-g-QPDMAEMA,the volume of DMAEMA was 13 mL,w?APS?was 1.2%,reaction temperature was 55?,reaction time was 16 h,and the grafting rate of PDMAEMA was30.43%.LS-g-QPDMAEMA was prepared when the mass of 2-chloroethylamine hydrochloride was 0.5 g,the reaction temperature was 60?and the reaction time was 14 h.LS-g-QPDMAEMA has good adsorption properties towards AuCl₄^-,and its adsorption capacity could reach 700.64 mg/g at 25?and pH value of 2.The selectivity coefficient of LS-g-QPDMAEMA towards AuCl₄^-relative to CuCl₄^2-was 11.The adsorption behavior obeyed the Pseudo-second-order kinetic model and Freundlich adsorption isotherm model.In addition,LS-g-QPDMAEMA also has better regeneration and reuse performance.The adsorbent D301-g-PDMC was obtained by using surface initiated graft polymerization method to graft the functional monomer methacryloxyethyltrimethyl ammonium chloride?DMC?onto the surface of D301 resin.In the process of preparation of D301-g-PDMC,the volume of DMC was 17 mL,w?APS?was 1.6%,reaction temperature was 35?,reaction time was 10 h,and the grafting rate of PDMC was 26.67%.D301-g-PDMC has good adsorption properties towards AuCl₄^-,and its adsorption capacity could reach 748.03 mg/g at25?and pH value of 2.The selectivity coefficient of D301-g-PDMC towards AuCl₄^-relative to CuCl₄^2-was 17.The adsorption efficiency could attain 97.83%when the mass of D301-g-PDMC was 0.15 g.The adsorption behavior obeyed the Pseudo-second-order kinetic model and Freundlich adsorption isotherm model.In addition,D301-g-PDMC showed excellent regeneration and reusability.The imprinting adsorbent D301-g-IIPDMC was prepared by the surface ion-imprinting method--"simultaneous graft polymerization and cross-linking imprinting",using AuCl₄^-as template ion,DMC as functional monomer,and MBA as crosslinking agent.In the preparation of D301-g-IIPDMC,w?MBA?was 12%,the volume of DMC was 1.7 mL,w?APS?was 1.5%,reaction temperature was 35?,reaction time was 10 h,n?AuCl₄^-?:n?DMC?was1:1,and the grafting rate of IIPDMC was 48.85%.D301-g-IIPDMC possessed very strong adsorption affinity and excellent recognition towards AuCl₄^-,and the adsorption capacity could reach 831.08 mg/g,and the adsorption efficiency could attain 97.25%when the mass of D301-g-IIPDMC was 0.05 g.The selectivity coefficient of D301-g-IIPDMC towards AuCl₄^-relative to CuCl₄^2-was 128,which increased 6.53 times compared with that before the imprinting process.The adsorption behavior was an endothermic spontaneous process,and fitted well with Pseudo-second order kinetic model and Freundlich adsorption isotherm model.Besides,D301-g-IIPDMC was desorbed easily and exhibits excellent reusability.