Biofriendly chitosan-based high-efficiency dialysis membrane

Chitosan, a biofriendly material, has a wide range of applications owing to its biocompatibility and biodegradability. We successfully prepared super-adsorbent membranes by dip-coating filter paper in chemically and physically modified chitosan solutions, and compared the urea adsorption performances of the different chitosan membranes. Chemical modification was achieved by successfully introducing carboxyl and amine groups into chitosan by carboxylation and amination using chloroacetic acid (ClCH₂CO₂H) and ethylenediamine (C2H4(NH2)2), respectively. Physical modification was performed by attempting different crosslinking reactions using sodium tripolyphosphate and copper ions (Cu2+). The effects of the various physical and chemical modifications was determined on the urea reduction ratio (URR). At a urea concentration of 500 ppm, the modified chitosan membranes exhibited URRs of >80 % within 2 h, a 38 % decrease in the equilibrium swelling ratio, and a 600 % increase in the bursting strength. These results demonstrate the immense potential of these membranes for hemodialysis in biomedical research. Lastly, model fitting revealed that the mechanisms of urea adsorption onto chitosan were best described using the Freundlich adsorption isotherm and the pseudo-second-order kinetic model.