اصلاح ساختاري و عملكردي غشاهاي دياليز با هدف دستيابي به تراوش بالا، پاكسازي تنظيم‌شده و خون‌سازگاري در فرايند تصفيه خون

Patients in end-stage renal disease are prescribed renal replacement therapy, one of which is hemodialysis. The dialysis membrane is the core of this system, facing challenges such as removing uremic toxins while preserving essential proteins and ensuring biocompatibility with blood. During hemodialysis, these patients also face increased inflammation and oxidative stress-related complications. To solve these challenges, polyvinyl alcohol, vitamin E in the membrane substrate and heparin and ethylenediaminetetraacetic acid were added to the polyacrylonitrile membrane surface. Surface and chemical characterization tests, including ATR and EDX, confirmed the presence of these modifiers in the membrane structure. The surface charge of the membranes was determined by PZC testing, and the effects of the modifiers on membrane roughness were assessed by AFM, while membrane pore morphology was examined by SEM. Blood compatibility tests, including coagulation time, hemolysis ratio, platelet adhesion, and protein adsorption, as well as antioxidant tests like DPPH and MDA, confirmed the blood compatibility and antioxidant properties of the membranes. Additionally, the effects of each modifier on filtration parameters (water flux, simulated blood flux, urea clearance, creatinine clearance, flux recovery ratio, and total fouling) were eva‎luated. Experimental design identified the key parameters influencing each response, leading to the optimization of the membrane. Modeling was also performed to predict flux and urea clearance, and the fouling mechanism was determined for each hour of filtration. Moreover, mass transfer mechanisms and resistances were established throughout the filtration process. Overall, the results showed that the addition of polyvinyl alcohol increased membrane porosity by up to 24%, creating a more uniform pore distribution and preventing complete pore blockage, thus enhancing membrane performance. Vitamin E improved the antioxidant properties of the membranes by up to 32% without negatively affecting flux, and it even increased urea clearance by 15%. Ethylenediaminetetraacetic acid increased the flux recovery ratio to 99% and reduced membrane resistance by up to 18%. Heparin increased clotting time by up to 5 times compared to the raw membrane and had significant effects on platelet adhesion and protein adsorption. Overall, the presence of these modifiers in the membrane structure reduced mass transfer resistance by up to 29%, increased urea clearance and flux, and provided improved blood compatibility and antioxidant properties.

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