Mixed matrix polysulfone/clay nanoparticles ultrafiltration membranes for water treatment

We studied the effect of clay nanoparticles (CN) with and without the use of polyethylene oxide (PEO) as the pore former on the structure and performance of mixed matrix polysulfone ultrafiltration membranes. The pure water permeability of the neat PS membrane was 15 L.m(-2) h(-1) bar(-1). The optimal dosage of the individually doped membranes was 1.5% weight CN to PS and 5% weight PEO to PS resulting in permeabilities of 56 and 237 L m(-2) h(-1) bar(-1), respectively. Additional experiments were completed comparing the control membrane to the membranes with 1.5% and 4.5% CN, 5% PEO, 1.5% CN + 5% PEO, and 4.5% CN + 5% PEO to determine dopants effects on pore microstructure, superficial charge, separation performance and fouling susceptibility. Simultaneous doping of the optimal individual dosages of both additives resulted in a membrane with a permeability of 192 L m(-2). h(-1) bar(-1). Changing the additive dosages for 4.5% CN and 5% PEO had a synergistic effect, resulting in a composite membrane with a permeability of 319 L m(-2) h(-1) bar(-1). In general, the use of CN improved membrane thermal/mechanical resistance and permeability with minimal loss in rejection. Membranes' molecular weight cut off ranged from 100 kg mol(-1) for the membrane with 1.5% weight of CN to more than 203 kg mol(-1) for the membrane with 5% weight PEO. Challenging tests with sodium alginate and natural water showed a lower fouling potential and higher flux recovery for the membranes cast with CN. Overall, the CN significantly improved all the evaluated characteristics of the obtained mixed matrix membranes.