Anti-fouling TiO2 nanowires membrane for oil/water separation: Synergetic effects of wettability and pore size

• DOI: 10.1016/j.memsci.2018.11.056
• Publication Date: 2018-11-23T21:41:44Z
• Authors: Zihe Pan; Sijing Cao; Jianfeng Li; Zhiping Du; Fangqin Cheng
• Keywords: Superhydrophilicity

Abstract TiO2 nanowires (NWs) membranes with varied wettability ranging from superhydrophilic to superhydrophobic have been facile fabricated via dip-coating for oil/water separation. Incorporating TiO2 NWs results in the increase of roughness and the formed hierarchical structure from TiO2 NWs micro-aggregations enlarges the wettability. Separation efficiency and permission flux of the as-prepared membranes increase first and decrease with the increment of TiO2 NWs. These superhydrophilic/hydrophilic membranes eliminate water from oil/water mixtures and the separation efficiency declines with the increasing water contact angle until the membrane lose the oil/water separation property at around 90°. Membranes with water contact angle of 90–100° cannot separate oil/water mixtures while membranes with water contact angle larger than 120° become oil-remove type with separation efficiency around ~ 99% and high permission flux. The study illustrates that relatively large pore size (~ 15 µm) attributes to the high separation efficiency and permission flux. The synergetic effects of wettability and pore size indicate that surface wettability is critical for efficient oil/water separation. Both hydrophilic and superhydrophilic membranes show high separation efficiency and outstanding anti-fouling performances after long term oil/water separation.