Antifouling improvement of PVC membranes by embedding nanodiamond in algae concentration

Separation of algae from water is one of the challenges of biological processes that require membranes with low fouling. Emulsion PVC-based (EPVC) ultrafiltration membranes were prepared via phase inversion using NMP as solvent and modified with detonation nanodiamonds (DNDs) at varying concentrations (0.1–2 wt%). The membranes were characterized by SEM, EDX, TGA, and water contact angle measurements. The membranes were evaluated for permeability, BSA rejection, and fouling resistance using a dead-end filtration system at 1.0 bar. Among all compositions, the membrane with 1 wt% DND showed the best performance, with high water flux (51 L/m².h), excellent BSA rejection (98.4%), and strong fouling resistance. Pressure-dependent testing confirmed stable performance up to 4 bar. These membranes were further applied for the separation and concentration of microalgal biomass from its cultivation medium under 0.2–1.2 bar. Visual inspection revealed increased surface fouling with pressure, yet removal efficiencies exceeded 97% for all conditions except 0.2 bar. At 1 bar, the maximum removal efficiency was recorded at 99.72%, indicating optimal separation performance. These findings highlight the potential of DND-modified EPVC membranes for enhancing the performance of UF membranes and for effective microalgal harvesting in bioresource applications.