The Synthesis Of The Polystyrene Base Modified Thiourea Resin And Its Adsorption Of Au (iii) Performance And Mechanism

Through the processes of aminition and esterification reactions on the material Chloromethylated polystyrene microsphere,polystyrene thiourea resins(PSTU) were synthesized.The adsorption properties and mechanism of PSTU resin to Au(Ⅲ) were studied in this paper.Bischloroformate was prepared by the reaction of bis(trichdomethyl) carbonate and diethylene glycol,catalyzed by N,N-dimethylaniline (DMA);Secondly,oxydiethane-2,1-diyl diisothiocyanatidate(ITC) were synthesized by the solid-liquid phase transfer catalysis reaction of bischloroformate and KSCN;then the amino resin was prepared by the reaction of Diethylenetriamine(DETA) and Chloromethylated polystyrene microsphere.Finally,ITC added with amino resin to prepare PSTU resin.The temperature,ratio and reaction time of aminition and esterification reactions were investigated.PSTU resins were charaterized by IR,elemental analysis,SEM,TG and so on.With batch method,the influence of adsorption duration,temperature,initial concentration of noble metals,concentration of HCl was studied.Adsorption capacity of PSTU to Au(Ⅲ) is 1.84 mmol·g^-1, under the following conditions:temperature is 30℃,initial concentration of noble metals is 1 mg·mL^-1,concentration of HCl is 1mol·L^-1.The adsorption process of PSTU to Au(Ⅲ) reached equilibrium after 28 hours. Adsorption capacities increase with the increase of temparature,the initial concentration of noble metals,effected hardly by acidity in the solution. Separation factor K_d of binary system highly rangs from 119 to 293, which revealed favorable selectivity for the noble metals.Adsorption isotherm,thermodynamics,kinetics were researched, and the adsorption mechanism of PSTU resin to Au(Ⅲ) was discussed. Isotherm adsorption process can be well described by Langmuir models, which indicats that the adsorption is a monolayer one;Enthalpy changeΔH of the process is plus,which demonstrated that adsorption process is endothermic;liquid film spreading is the predominant step of the adsorption process;IR contrastive analysis before and after adsorption reveal that Au(Ⅲ) coordinate with the resins in the adsorption process.