Preparation And Adsorption Properties Of Ion Imprinted Materials Based On Fulvic Acid

Ion imprinted material,as a new organic polymer adsorption material,has a great application prospect in separation and enrichment of metal ions.Single metal ion can be identified and adsorbed specifically by ion imprinted material.After a series of experiments,different ion imprinted polymers,which is used to absorb Cd²⁺ with a good selectivity,were synthesized and analyzed based on the fulvic acid?FA?as basic material.1)Modified fulvic acid?MFA?,based on FA and epoxy chloropropane as materials,was synthesized under the condition of alkaline.The modification technological condition of FA was optimized.Under optimal reaction conditions,the highest epoxide equivalent of product is 0.88 mol/100 g?the optimization of process conditions is that,Rate of charge,reaction time and reaction temperature?.Structure and surface appearance of FA and MFA were analysised with FT-IR,UV and SEM,respectively.2)MFA-IIP was synthesized by inversing suspension copolymerization,with MFA as functional monomer and ethylenediamine as cross-linking agent.FT-IR,SEM and TG were used to analysis structure and characterization of MFA-IIP.Adsorption capacity of MFA-IIP was researched by FAAS.Optimal reaction condition is that the dosage of MFA is 0.5000 g,the amounts of Cd²⁺?3.0 g/L?and ethanediamine are 30 mL and 20 m L respectively,reaction time and temperature are 12 h and 60? respectively.After recycling for 3⁴ times,MFA-IIP can sustain its structure properties and adsorption capacity.3)MFA-M-IIP was prepared with Fe₃O₄/SiO₂,MFA and KH-550 as magnetic core,functional monomer and cross-linking agent,respectively.Good paramagnetism of MFAM-IIP is beneficial to separate products simply and quickly.Under the optimal condition,adsorption quantity and removal rate of MFA-M-IIP to Cd²⁺are 2.48 mg/g and 99.37%.After competitive adsorption experiment,the selectivity coefficient of Cd²⁺/Pb²⁺ and Cd²⁺/Cr3+ are 79.68 and 136.82,respectively.Adsorption behavior of MFA-M-IIP to Cd²⁺can be described by pseudo-second-order kinetic model and Langmuir isotherm.