Research On The Preparation, Performance And Application Of Rh(Ⅲ) And Pd(Ⅱ) Ionic Surface Imprinted Polymers

Palladium and rhodium are important noble metal elements,which have unique physical and chemical properties and are used in many fields.Therefore,it is important for us to study their separation and enrichment methods.On the basis of consulting a large number of literatures,combined with the advantages of surface ion-imprinted polymers with good selectivity and simple preparation method,the preparation of Rh（Ⅲ）and Pd（Ⅱ）surface imprinted polymers and it’s application research work on separation and enrichment of Rh（Ⅲ）and Pd（Ⅱ）as materials are studied.The specific work is as follows:Firstly,a functional monomer,1-methacrylamide-1,2,4-triazole（MAT）,was synthesized from 1,2,4-triazole as a raw material.Then,we used the ethylenated multi-walled carbon nanptubes as carriers and as the template ion,Orthogonal experimental design method was used to optimize the amount of monomer,cross-linking agent（EGDMA）and carrier.Surface ion-imprinted polymer Rh（Ⅲ）-ⅡP@VMWCN was synthesized by using 0.1 mmol of template Na₃（RhCl₆）,0.5mmol of MAT,3 mmol of EGDMA and 0.125 g of carrier.The FTIR,SEM and nitrogen adsorption experiments were used to characterize the structure and morphology of the imprinted polymer.The adsorption properties and the application value of the solid phase extractant were studied.The results showed that the imprinting factors of the imprinted polymer was 1.87 and the equilibrium adsorption capacity was 3.55 mg/g,the recoveries of the solid phase extraction column for Rh（Ⅲ）were 68%,and the extraction rate of coexisting ions(Fe³⁺、Cu²⁺、Ni²⁺and Pd²⁺)was all below 16%.Secondly,Silica gel（SiO₂-KH570）modified with 3-（trimethoxysilyl）propyl methacrylate（KH570）was as carrier.The mixed monomer MAA-KH550 obtained by the reaction ofα-methacrylic acid（MAA）and 3-aminopropyltriethoxysilane is a functional monomer and the amount of functional monomer,carrier and crosslinking agent EGDMA is optimized one by one.After that,Surface ion-imprinted polymer Rh（Ⅲ）@SiO₂-KH570 was prepared by 0.1 mmol of template Na₃（RhCl₆）,0.4 mmol ofmonomer,0.08g of carrier and 3 mmol of EGDMA by graft copolymerization on the surface of silica gel.The structure and morphology of the imprinted polymer were characterized by FTIR,SEM and nitrogen adsorption experiments.The adsorption properties and application performance in solid phase extraction were also studied.The results showed that the equilibrium adsorption capacity of the imprinted polymer was3.20 mg/g and the imprinting factor was 2.32.The recoveries of Rh（Ⅲ）were 67%and the extraction rate of interfering ions(Fe³⁺、Cu²⁺、Ni²⁺and Pd²⁺)was below 15%.Thirdly,A salen ligand N,N’-bis（3-propenyl salicylaldehyde）o-phenylenediamine（BASP）was prepared from o-phthalamide,bromopropene and salicylaldehyde.Then,it was used as functional monomer and the modified silica gel as carrier.After optimizing the amount of monomer,carrier and crosslinker,surface ion-imprinted polymer Pd（Ⅱ）-ⅡP@SiO₂-KH570 was prepared by 0.1 mmol of template Na₂PdCl₄,0.11 g of carrier SiO₂-KH570,0.4 mmol of monomer BASP and 3mmol of crosslinking agent EGDMA.The morphology and structure of Pd（Ⅱ）-ⅡP@SiO₂-KH570 was characterized by FTIR,SEM and we also studied its adsorption performance and application in solid phase extraction.The results showed that the equilibrium adsorption capacity of the imprinted polymer was 6.19 mg/g and the imprinting factor was 2.28 in 10 mL of 0.02mg/mL Pd（Ⅱ）ion solution.In the case where most of the coexisting ions are eluted,the recoveries of Pd（Ⅱ）can reach 70%and the extraction rate of interfering ions(Fe³⁺、Cu²⁺、Ni²⁺and Rh³⁺)was no more than 17%.