An efficient anti-fouling strategy involving in-situ aeration and dielectrophoresis by using high salinity seawater for oily wastewater treatment

Abstract

Membrane fouling is a significant barrier to the development of membrane separation processes, particularly in the treatment of oily wastewater resulting from frequent offshore oil spills. A green and sustainable solution is imperative to address this environmental concern. This paper presents a novel method involving the in-situ growth of superhydrophilic TiSe2 nanospheres on foam titanium via a one-step hydrothermal method. Supported by an external electric field, a dual anti-fouling strategy involving in-situ aeration and dielectrophoresis was developed, resulting in a remarkably improved fouling resistance by 90 %. Unlike prior methods focusing predominantly on developing super-wettability surfaces for passive anti-fouling, the strategy in this work leveraged the high salinity inherent in seawater to introduce in-situ aeration and dielectrophoresis forces to the filtration process. This innovative approach actively prevented oil droplets from contacting the filtration material surface, achieving effective active anti-fouling. The synthesized TiSe2/TF(TTF) demonstrated separation efficiencies of over 99 % for four different oil-in-water emulsions. Additionally, this work innovatively incorporated Transition State Theory (TST) and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory as supplementary evidence for the hydrophilicity of the filtration material. It is worth mentioning that even after four continuous months of filtration experiments, the TTF material maintained a rejection rate of over 99 % with only a slight decrease in pure water flux, showcasing its exceptional durability. This work provided a feasible and innovative solution for treating daily and offshore oily wastewater, laying a foundation for future research and practical applications in environmental water treatment.