Study On The Preparation, Performance And Application Of Three New Types Of Pd(?) Ionic Surface Imprinted Polymers

Palladium is an important precious metal element with a wide range of uses,so its separation and enrichment is of great significance.The imprinted polymer,especially the surface-imprinted polymer,is widely used as a separation material for the separation and enrichment of trace components because of its high selectivity for adsorption,simple preparation and reusability for the target molecule.However,the surface imprinted polymer of Pd(?)with nanometer material as carrier has not been reported.In this paper,two new functional monomers were synthesized according to the coordination characteristics of Pd(?).At the same time,the preparation and application of Pd(?)ion surface imprinting polymer were studied by selecting multi-walled carbon nanotubes and nano-TiO2 as the carrier,the specific research contents are as follows:Firstly,a new functional monomer,2-(N-allyl)aminopyridine(AAP),was synthesized from 2-aminopyridine as a raw material.Then,the ethylated multi-walled carbon nanotubes(MWCNTs)were used as carriers,and the polymerization conditions were optimized by orthogonal design.Pd(?)-AAP-IIP@MWCNTs was synthesized by using 0.075 g ethylenically amino MWCNTs as carrier,0.4 mmol of N-allylpyridin-2-amine as the functional monomer,5 mmol of EGDMA as the cross-linker,and 0.1 mmol Na2PdCl4 as template.The structure,morphology,adsorption properties and application prospect of Pd(?)-AAP-IIP @ MWCNTs were characterized by FTIR,TEM,SEM,adsorption and solid phase extraction experiments.The results showed that the equilibrium adsorption capacity and imprinting factor of the Pd(?)-AAP-IIP@MWCNTs for Pd(?)ion were found to be 9.053 mg/g and 3.46,respectively.The adsorption rate of Pd(?)ion was above 90%and the extraction rate was 74%under the optimized extraction conditions.The extraction rate of other coexisting ions was below 12%,the solid phase extraction method and ICP-OES were used to determine the Pd(?)ion in the water sample.The recoveries was 91.6%and the relative standard deviations was 2.47%.Secondly,another new functional monomer,1-methacryloylbenzotriazole(MAB)with nitrogen-containing heterocyclic ring was synthesized from 1H-benzotriazole as the starting material.MWCNTs was used as carriers.After the polymerization conditions were optimized by orthogonal design,Pd(?)-MAB-IIP @ MWCNTs was prepared by 0.1 mmol of template Na2PdCl4,0.1 g of carrier MWCNTs,0.4 mmol of functional monomer MAB and 3 mmol of crosslinking agent EGDMA.The structure,morphology,adsorption properties and application prospect of Pd(?)-MAB-IIP @MWCNTs were characterized by FTIR,TEM,SEM,adsorption and solid phase extraction experiments.The equilibrium adsorption capacity and the imprinting factor of Pd(?)-MAB-IIP @ MWCNTs to Pd(?)ion were 6.88 mg/g and 1.81,respectively.The adsorption rate of Pd(?)ion was 94.78%under optimized extraction conditions,the extraction rate was close to 80%,and the extraction rate of other coexisting ions was below 13%.The solid phase extraction method and ICP-OES were carried out for the determination of Pd(?)ion.The recoveries was 84.2%and the relative standard deviations was 4.06%.Thirdly,We chose 2-Acetylaminoacrylic acid(AAA)as the functional monomer after comparing the adsorption capacity and the imprinting factor of the Pd(?)surface imprinted polymer(Pd(?)-IIP @ TiO2)prepared with different functional monomers,and further optimized the dosage of nano-TiO2,functional monomer AAA,crosslinking agent EGDMA and porogen methanol by orthogonal design method.Finally,Pd(II)-IIP@TiO2 was prepared by 7.5 mL of methanol as porogen,0.5 g of nano-TiO2 as the carrier,0.5 mmol of the AAA as the functional monomer,3 mmol of EGDMA as the crosslinking and AIBN as initiator at 60 ?.The adsorption capacity of Pd(II)was 2.543 mg/g and the imprinting factor was 2.46 in 5 mL of 13.0 mg/L Pd(II)ion solution.The adsorption rate was above 90%,the extraction rate was 66.47%,and the extraction rate of other coexisting ions was below 15%under optimized extraction conditions.The solid phase extraction method and ICP-OES were carried out for the determination of Pd(II)ion.The recoveries were 83.7%and the relative standard deviations were 4.32%.