Simple yet powerful nanofilters with tunable pore sizes and superhydrophilicity-underwater superoleophobicity for oil spill treatment

Abstract

Using filtration materials possessing superhydrophilic-underwater superoleophobic property to separate oil/water mixtures has become a research hotspot. However, most of the works are concentrated on building filtration materials with special wettability, ignoring the pore structures. Herein, polydopamine-modified (PDA-modified) nanofibrous mats with tunable pore sizes and special wettability were prepared by combining the electrospinning technique with a very simple modification process for oil/water separation. The results indicated that the pore structure of the PDA-modified nanofibrous mats could be finely modulated by utilizing different kinds of stainless steel wire meshes as collectors, and more interesting was that all the modified nanofibrous mats showed superhydrophilicity-underwater superoleophobicity. For the oil/water separation, the PDA-modified nanofibrous mats displayed high efficiency and high flux in separating oil/water mixtures, and the water flux could be highly improved by controlling the pore size and the optimal flux was high up to 40,405 L m−2 h−1. In addition, the PDA-modified nanofibrous mats exhibited excellent durability and recyclability. Finally, as a proof of concept a novel oil collection device based on the PDA-modified nanofibrous mat was constructed to in situ separate the oil/water mixtures and collect the oil simultaneously. The developed PDA-modified nanofibrous mats would have wide applications in oily wastewater separation and purification.