Adsorptive removal of p-cresol and creatinine from simulated serum using porous polyethersulfone mixed-matrix membranes

In this study, porous polyethersulfone mixed-matrix membranes incorporating the adsorbents activated carbon (AC), zeolite ZSM-5, and graphene oxide (GO) were prepared via non-solvent-induced phase inversion. Such types of membranes were designed for the removal of uremic toxins, making the connection between hemodialysis and hemoadsorption more smooth. The optimal conditions (for example, compositions of the polymer solution and non-solvent bath) for preparing such composite membranes were first determined and their physicochemical properties and pore structures were characterized. Under the conditions studied, batch adsorption of p-cresol and creatinine from simulated serum on the prepared membranes reached the equilibrium within 24 h. Based on the measured isotherms at 37 °C, the Langmuir adsorption capacity of p-cresol and creatinine on the AC-incorporated membrane were obtained to be 108.7 mg and 133.3 mg, respectively, per gram of the membrane. In a closed-loop dynamic experiment for the clearance of p-cresol and creatinine from binary solutions at 37 °C, the preferential ability of these membranes for p-cresol adsorption was demonstrated; for example, 80.0% and 7.4% of p-cresol (initially, 50 mg/L) and creatinine (initially, 150 mg/L) were removed with the help of AC-incorporated membrane, respectively, within 4 h (volume 0.5 L and membrane area 58.9 cm²). The viability of fibroblast NIH/3T3 cells and hemocompatibility in the presence of the prepared mixed-matrix membranes was finally examined.