Preparation And Adsorption Properties Of Surface Imprinted Materials

Among many techniques for preparing adsorbents,surface imprinting techniques have been widely used in the enrichment of rare ions and pre-treatment before detection due to the ability to prepare polymers with specific recognition capabilities in recent years.In this paper,ion and molecular imprinted polymers were prepared by surface imprinting.The preparation conditions and adsorption conditions were investigated,which provided important guiding significance for subsequent applications.In the study of ion-imprinted polymers,bromide ion which has important applications in the industry was selected as research objects.Bromine ion imprinted polymers(Br(I)-IIPs)were synthesized with chitosan modified by aluminum nitrate as functional monomer and glutaraldehyde as cross-linking agent.The results of adsorption conditions showed that the maximum adsorption capacity of Br(I)-IIPs and Br(I)-NIPs was achieved at the initial concentration of 100 mg-L-1 and the pH of the solution was 4.0,and the imprinting factor was 1.82.The adsorption capacity of Br(Ⅰ)-IIPs reaches up to its maximum value at 90 min,which was consistent with the pseudo-secondary adsorption kinetics model.Br(Ⅰ)-IIPs still have good adsorption selectivity for Br(Ⅰ)in binary mixtures of Br(Ⅰ)/F(Ⅰ),Br(Ⅰ)/Cl(Ⅰ),Br(Ⅰ)/I(Ⅰ).Meanwhile,the Br(Ⅰ)-IIPs have good recyclability.In the study of molecularly imprinted polymers,theophylline was selected as the research object.Preparation of theophylline molecularly imprinted polymers(THP-MIPs)using vinyl modified silica as the matrix,theophylline as the template molecule,MAA as the functional monomer,and hydrogen bonding in the solvent acetonitrile/trichloromethane(v/v=5/1).The electrostatic action formed a prepolymer and then carried on subsequent process.Finally the template was eluted with methanol/glacial acetic acid(v/v=9/1)as eluent.The characterization of the THP-MIPs were carried out by various characterization methods.The results of adsorption conditions showed that the maximum adsorption capacity of THP-MIPs and THP-NIPs was achieved at the initial concentration of 200 mg·L-1 and the pH of the solution was 7.0,and the imprinting factor was 1.26.The adsorption capacity of THP-MIPs reaches up to its maximum value at 60 min,which was consistent with the pseudo-secondary adsorption kinetics model.The prepared THP-MIPs can still recognize theophylline molecules well in the binary mixture of theophylline/theobromine(THP/THB)and theophylline/hypoxanthine(THP/HYX).Meanwhile,the THP-MIPs have good recyclability.In this study,bromine ion imprinted material and theophylline molecular imprinted material were successfully prepared based on surface imprinting technology,which has important guiding significance for the practical application of the pretreatment of seawater extraction bromine and theophylline wastewater before detection.