Preparation and Bilirubin Adsorption Property of Functional Microsphere PEI-CPGMA

Microbeads of poly glycidyl methacrylate(CPGMA) were synthesized with an average diameter of 100 μm adopting suspension method with ethylene glycol dimethacrylate as crosslinking agent,polyethylenimine(PEI) was then grafted on the surface of the CPGMA microsphere via the ring-opening reaction between the epoxy groups of PGMA and the amino groups of PEI,to form microspheres of PEI-CPGMA.The adsorption property of the microsphere for bilirubin was studied,and the effects of various factors,such as pH value,ionic strength of the medium and the grafting degree of PEI,on the adsorption property of microspheres were examined.The static adsorption experiment results show that PEI-CPGMA microspheres have strong adsorption towards bilirubin.The strong adsorption is attributed to the electrostatic interaction between the protonized amino groups of PEI and the dissociated carboxyl groups of bilirubin.The isothermal adsorption can be fitted to Freundlich equation,and the saturated adsorption can reach up to 14.1 mg/g.The pH value of the aqueous solution has great effect on the adsorption property of PEI-CPGMA microsphere.In near neutral solution(pH=6),the adsorption reachs maximum,while decreased in either acidic or basic solutions.Ionic strength of the medium has slight effect on the adsorption property of PEI-CPGMA microsphere.