Characterization of polyethylenimine grafted and Cibacron Blue F3GA immobilized poly(hydroxyethylmethacrylate-co-glycydylmethacrylate) membranes and application to bilirubin removal from human serum

In this study, acrylic hydrogel copolymer membrane was synthesized from 2-hydroxyethylmethacrylate (HEMA) and glycidyl methacrylate (GMA) monomers. The polyethylenimine polymer was then grafted onto membrane surface (poly(HEMA-co-GMA)-PEI). A dye–ligand (i.e., Cibacron Blue F3GA) was then covalently immobilized on the membrane through the amino groups of the polyethylenimine molecules (poly(HEMA-co-GMA)-PEI-CB). Both affinity membranes were used for the removal of bilirubin (BR) from aqueous solutions and human serum. The effects of pH, ionic strength, temperature and initial BR concentration on the adsorption capacity of both affinity membranes were investigated in a batch system. Separation of BR from human serum was also investigated in a batch system. Experimental data indicate that poly(HEMA-co-GMA)-PEI affinity membrane shows more adsorption capacity to BR than that of the poly(HEMA-co-GMA)-PEI-CB membrane, which may be explained on the basis of opposite charge on both PEI and BR. The BR adsorption on the poly(HEMA-co-GMA)-PEI and poly(HEMA-co-GMA)-PEI-CB affinity membrane did not well described by the Langmuir model, but obeyed the Freundlich isotherm model. The poly(HEMA-co-GMA)-PEI and poly(HEMA-co-GMA)-PEI-CB affinity membranes are stable when subjected to sanitization with sodium hydroxide after repeated adsorption–desorption cycles.