Incorporation of kappa-carrageenan as additive for morphological and performance enhancement of nanohybrid polysulfone / silver-graphene oxide membranes

Membranes have been widely used in the process of treatment of water and wastewater. PSf membranes exhibit robustness and flexibility. Nevertheless, the hydrophobic nature of PSf impedes the flow of water and reduces the effectiveness of membrane filtration. Hence, the properties of PSf membranes can be enhanced with the incorporation of kappa-carrageenan (k-car), an extremely hydrophilic biopolymer. This study examined the use of k-car, a biopolymer made up of anionic polysaccharides derived from certain species of ocean red algae. The goal was to address issues connected to the membrane's hydrophilicity and selectivity. The membranes produced with various percentages of k-cars (0.1 wt%, 0.25 wt%, 0.5 wt%, 0.75 wt%, and 1.0 wt%) are identified as Cl, C2, C3, C4, and C5, respectively. The PSf/k-car membranes underwent characterization using FTIR, water contact angle (WCA) goniometer, FESEM, salt and dye rejection. The inclusion of k-car substantially enhanced the hydrophilic properties of PSf membranes. The results indicated that the 0.25 wt.% kcar addition resulted in the maximum porosity, reaching 79%. The presence of an extra -OH signal at 3385.31 cm-I in the nanohybrid membrane's FTIR spectra suggests an enhanced hydrophilicity, possibly due to the hydroxyl (-0H) groups of k-car. The water contact angle of the manufactured membranes reduced from 68.52 0 to 43.28 0, indicating an improvement in their hydrophilicity. Compared to the pure PSf membrane, the arrangement of the finger-like structure of the manufactured nanohybrid membrane is slightly curved with a bigger lower section. Out of all the artificial membranes, C2 demonstrated the highest level of salt removal, reaching up to 97%. This discovery demonstrated that the inclusion of 0.25 wt% k-cars significantly improved both the water permeability of the membrane and its ability to reject salt and dye. Overall, the addition of k-car as a substance that creates pores in the PSf membrane has significantly affected its ability to attract water, its ability to selectively allow certain substances to pass through, and its physical structure.