*Principles of Membrane Surface Modification for Water Applications DOI: http://dx.doi.org/10.5772/intechopen.96366*

to the hydrogen bonding force and more electrostatic repulsion properties of sTiO2 NPs. The same group has also investigated the effect of the addition of sulfonated graphene oxide (sGO) NPs into PVDF membranes fabricated by the phase inversion method [89]. A gradual increase in water fluxes was obtained up to the sGO loading concentration of 0.8% meaning to the elimination of aggregation. Maximum water permeability attained at the 0.8 wt% of sGO addition was reported as 146% higher than the neat PVDF. The enhancement of the water flux has been explained by the improved charge density due to the availability of extra sulfonic groups on sGO supports that can attract more water layer. In addition, the attached –SO3H group in sGO provides stronger hydrogen-bonding with respect to –OH/-COOH groups available in native GO. The performances of the CNT and sulfonated CNT (sCNT) NPs blended PVDF UF membranes were compared for the objective of conserving the bacterial population and providing antifouling property [90]. The porosity, pore size, water flux, fouling recovery ratio values of PVDF-CNT and PVDF-sCNT were obtained as 81 and 84%, 50 and 60 nm, 360 and 680 L/m2.h and 72.7 and 83.5%, respectively. In addition, the BSA (bovine serum albumin) rejection was 90% in the PVDF-sCNT. Authors demonstrated that the fabricated composite membranes were nontoxic to the bacterial population, hence the proposed membrane architecture can be a promising approach for membrane bioreactor systems in wastewater treatment plants.
