Nanocomposite Polysulfone/CB Modified by Melt Extrusion and Solution Mixing for Enhanced Removal of Uremic Toxins

In this study, polysulfone-based nanocomposites with carbon black (CB) nanoparticles were fabricated to evaluate their urea-removal properties. The nanocomposites were obtained using two different methods: solution mixing and melt extrusion. These materials were evaluated using Fourier transform infrared spectroscopy (FTIR), which allowed for the identification of the corresponding functional groups within the polysulfone polymer matrix. X-ray diffraction (XRD) analysis was performed, confirming the amorphous structure of the polysulfone. The addition of modified carbon black shifted the most intense peak of the polysulfone. Thermogravimetric analysis (TGA) showed an increase in thermal stability with the addition of different concentrations of modified carbon black for solution-mixing method. Scanning electron microscopy (SEM) revealed that the melt-extrusion method presented a better dispersion of the nanoparticles, since large agglomerates were not observed. Additionally, a urea adsorption study was conducted, obtaining removal percentages of 76% and 72% for the extrusion and solution-mixing methods, respectively. It was demonstrated that the nanocomposite can be used for up to five cycles without losing urea-removal efficiency, whereas the efficiency of pure polysulfone decreases as the number of cycles increases. Finally, the hemolysis test was performed, and the nanocomposites showed less than 1% hemolysis, indicating that the material is non-hemolytic.