Intensification of the ultrafiltration of real oil-contaminated (produced) water with pre-ozonation and/or with TiO2, TiO2/CNT nanomaterial-coated membrane surfaces
Gábor Veréb, Péter Kassai, Érika Nascimbén Santos, G. Arthanareeswaran, Cecília Hodúr, Zsuzsanna László
Abstract
Abstract In the present study, commercial PES, PVDF, PTFE ultrafilter membranes, and two different nanomaterial (TiO 2 and TiO 2 /CNT composite)-covered PVDF ultrafilter membranes (MWCO = 100 kDa) were used for the purification of an industrial oil-contaminated (produced) wastewater, with and without ozone pretreatment to compare the achievable fouling mitigations by the mentioned surface modifications and/or pre-ozonation. Fluxes, filtration resistances, foulings, and purification efficiencies were compared in detail. Pre-ozonation was able to reduce the total filtration resistance in all cases (up to 50%), independently from the membrane material. During the application of nanomaterial-modified membranes were by far the lowest filtration resistances measured, and in these cases, pre-ozonation resulted in a slight further reduction (11–13%) of the total filtration resistance. The oil removal efficiency was 83–91% in the case of commercial membranes and > 98% in the case of modified membranes. Moreover, the highest fluxes (301–362 L m −2 h −1 ) were also measured in the case of modified membranes. Overall, the utilization of nanomaterial-modified membranes was more beneficial than pre-ozonation, but with the combination of these methods, slightly higher fluxes, lower filtration resistances, and better antifouling properties were achieved; however, pre-ozonation slightly decreased the oil removal efficiency.