| Currently, a focus is quite concerned that recovery of small amount of gold about low concentrations of gold-bearing waste solution in gold field. Under the dual benefits of environmental protection and economic, it is particularly urgent and meaningful to seek an efficient and green gold-extracting methods. In this study,three kinds of grafted materials were prepared by an appropriate method of grafting, and its adsorption abilities towards AuCl4-were researched preliminary. Then, using noval surface molecular(ions) imprinting technology established by our research group, three kinds of AuCl4- imprinted materials were prepared and its adsorption performance and recongnizing mechanism towards template ion AuCl4- were researched. The prepared Ionic surface imprinted materials possess efficient adsorption and recognition performance, which have great scientific significance and research value.A functional grafted material SiO2-g-PEI was prepared via grafting functional polymer PEI (polyethyleneimine, PEI) onto the surface of silica gel particles. Using surface ion imprinting technology, PEI macromolecules grafted onto the surface of silica gel particles was crosslinked using AuCl4- as template ions and ethylene glycol diglycidyl ether (EGDE) as crosslinking agent, ionic imprinted material SiO2-g-IIPPEI was obtained. The adsorption characteristics of SiO2-g-PEI and SiO2-g-IIPPEI for AuCl4- were investigated through static method. The experiment results shows that saturated adsorption capacity of grafted material SiO2-g-PEI for AuCl4- is 13.29 mg/g, the adsorption is physical adsorption with monomolecular layer and adsorption process obey second-order kinetic model. The adsorption capacity of the ionic imprinted material SiO2-g-IIPPEI could reach to 23.59 mg/g, and the relative selectivity coefficients relative to Cu2+ is 32.45, which exhibits excellent adsorption performance and strong ability of memories recognition of the ionic imprinted material SiO2-g-IIPPEI for AuCl4-. Furthermore, SiO2-g-IIPPEI also possesses excellent reusability.Using WDA918 resin as the carrier, Polyethyleneimine macromer was grafted to the surface of WDA918 resin by epichlorohydrin, and the grafted material WDA918-g-PEI was obtained. According to the similar prepared methods to SiO2-g-IIPPEI, imprinted material WDA918-g-IIPPEI was obtained. The adsorption characteristics and regeneration performance of WDA918-g-PEI and WDA918-g-IIPPEI for AuCl4- were investigated through static method. The experiment results shows that the static adsorption capacity of WDA918-g-PEI can reach to 34.98 mg/g at 25℃ and pH of 2. The static adsorption capacity of ionic imprinted material WDA918-g-IIPPEI can reach to 76.18 mg/g at 25℃ and pH of 2. Compared with WDA918-g-PEI, the adsorption capacity of WDA918-g-IIPPEI increased by 2 times and exhibiting excellent adsorption properties for AuCl4- The relative selectivity coefficients relative to Cu2+ is 278, which exhibits excellent adsorption performance and strong ability of memories recognition of the ionic imprinted material WDA918-g-IIPPEI for AuCl4-. Additional, WDA918-g-IIPPEI possesses excellent regeneration and reusability.Glycidyl methacrylate (GMA) was grafted onto the surfaces of D301 resin to obtain grafting material D301-g-PGMA by using oxidation-reduction initiating system constituted by the amino groups of D301 resin and ammonium persulfate in the solution. Then by ring-opening reaction between epoxy groups of PGMA molecular chain and amine groups in the ethylenediamine, realizing amino modified of grafted material, and the functional adsorbent material D301-g-APGMA was Obtained. According to surface ion imprinting technology, ionic imprinted material D301-g-IIPAPGMA was obtained by using AuCl4- as template ions and ethylene glycol diglycidyl ether (EGDE) as crosslinking agent. The adsorption characteristics and regeneration performance of D301-g-APGMA and D301-g-IIPAPGMA for AuCl4- were investigated through static method and dynamic method. The research results showed that grafting rate of PGMA could be as high as 41.15% under the conditions of GMA dosage 10 mL, w(APS) 1.5%, reaction time 18 h, and reaction temperature 40℃. The ring-opening rate of epoxy bond of D301-g-PGMA can reach 91.67% when reaction time is 8 h and reaction temperature is 90℃. The static adsorption capacity of D301-g-APGMA can reach to 276.74 mg/g at 25℃ and pH of 2. The relative selectivity coefficients relative to Cu2+ and Fe3+ are 713 and 374, respectively. Compared with the D301 resin, the adsorption ability and selected performance of D301-g-APGMA toward AuCl4- was greatly improved. Under the same conditions, the static adsorption capacity of ionic imprinted material D301-g-IIPAPGMA can reach to 335.25 mg/g at 25℃ and pH of 2. The relative selectivity coefficients relative to Cu2+ is 895, which exhibits excellent adsorption performance and strong ability of memories recognition of the ionic imprinted material D301-g-IIPAPGMA for AuCl4-. Additional, D301-g-IIPAPGMA possesses excellent regeneration and reusability. |
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