Study On Pd(Ⅱ)ion Imprinted Polymer By Nanometer Material As Carrier

Allowing for the unsatisfactory selectivity,low separation efficiency,high cost and environmental unfriendliness of existing methods and materials for separation and enrichment of Pd(II)5 the methods with ion-imprinted polymers,especially surface ion-imprinted polymers,exhibit the advantages of simple preparation,environmental friendliness,fast separation and enrichment,and high selectivity.In this paper,according to the coordination characteristics of Pd(II),two new functional monomers,which are mainly coordinated by nitrogen atoms from them were designed and synthesized.Then the preparation and application of Pd(Ⅱ)surface imprinted polymers were studied by choosing different nanomaterials as carriers.The specific research contents are shown as follows:Firstly,a functional monomer(MTet)containing multiple nitric heterocycle-s was synthesized from 5-aminotetrazole.Then Na2PdCl4 and carbon nanotubs were used as the template and the carrier,respectively.The polymerization conditions were optimized by single variable method.Finally,0.3 mmol MTet,0.1 mmol Na2PdCl4,4.0 mmolcrosslinker(EGDMA)and 0.1 g ethylenized carbon nanotubes were selected and usedto synthesize a Pd(Ⅱ)surface imprinted polymer(Pd(Ⅱ)-MTet-IIP@VMWCNTs)by surface imprinting technique.Its structure and morphology were characterized by SEM,TEM and FTIR.Its adso-rption and application performance were studied by adsorption experiments and solid phase extraction experiments.The results showed that the adsorption capacity of Pd(Ⅱ)-MTet-IIP@VMWCNTs was excellent(32 mg/g)with high imprinting factor of 1.93.The adsorption behaviorsof Pd(Ⅱ)-MTet-IIP@VMW-CNTs conformed to the quasi-second-order kinetic adsorption model.Under the optimum solid phase extraction conditions,the solid phase extraction column prepared by these polymers has high loa-ding capacity(65 mg/g)and preferable adsorptive selectivity.The selectivity coefficientof Solid phase extraction for Pt2+,Zn2+,Nit+,Cu2+ and Tb3+ were 3.2,5.1,16.0,4.7 and 3.5,respectively,the solid phase extraction column was used for the separation and enrichment of Pd(Ⅱ)in Green Lake.The recovery rate was over 66%,and the relative standard deviation was 1.04%(n=3).Secondly,a new functional monomer(MAS)containing imines was synthesized from 2-pyridylformylhydrazide and allylic chloride.Then vinyl carbon nanotubes(CNTs)were used as the carriers.After single variable method was used to screen the conditions for the synthesis of polymers,0.1 mmol template Na2PdCl4,0.3 mmol monomer MAS,5.0 mmol crosslinking agent EGDMA and 0.1g carrier were chosen as as polymerization conditions.The results show that the adsorption behaviors of imprinted polymer(Pd(Ⅱ)-MAS-IIP@VMWCNTs)prepared under the optimized conditions conforms to the quasi-second-order kinetic adsorption model,and has high adsorption capacity(equilibrium adsorption capacity is 20.94 mg)imprinting factor(2.67)and excellent adsorption selectivity.The adsorption selectivity coefficients of Ce3+,Zn2+,Fe3,,Rh3+,Tb3,,Ag+,and Pt2+ are 26.8,20.9,24.9,14.9,10.9,8.2,6.3 and 4.3,respectively.The maximum loading of the solid phase extraction column(Pd(Ⅱ)-MAS-IIP@VMWCNTs-SPE)prepared by these polymers is 63 mg/g,which could meet the requirements of separation and enrichment of trace Pd(II).Pd(Ⅱ)-MAS-IIP@VMW CNTs-SPE was used for the separation and enrichment of Pd(Ⅱ)in catalyst samples.The recovery was 67.14%,and the relative standard deviation was 0.89%(n=3),Thirdly,with 4-vinylpyridine as functional monomers,o-aminopyridine as ligands and nano-titanium dioxide as carriers,a Pd(Ⅱ)-IIP@TiO2 ion surface imprinted polymer(Pd(II)-IIP@TiO2)was synthesized by single variable method.Its structure,morphology adsorption and application performances were studied by SEM,TEM,FTIR and static adsorption experiments.The results showed that when Na2PdCl4 was 0.1 mmol,4-vinylpyridine was 0.6 mmol,o-aminopyridine was 0.4 mmol and EGDNA was 6.0 mmol,the prepared Pd(II)-IIP@TiO2 had the highest adsorption capacity(52.6 mg/g),the highest imprinting factor(4.0)and good adsorption selectivity.The adsorption selectivity coefficients of Fe(Ⅲ),Zn(Ⅱ),Tb(Ⅲ),Pt(Ⅱ),Rh(Ⅲ),Cu(Ⅱ)and Ag(Ⅰ)were 13.1,10.9,10.2,6.19,5.97 and 4.1,respectively.The recovery of Pd(Ⅱ)in Cuihu Lake ranged from 81.1%to 89.4%,and the relative standard deviation was less than 3.24%(n=3).