Weijun Li

Underwater superoleophobic palygorskite coated meshes for efficient oil/water separation

Oil/water separation has recently become a global challenging task due to frequent oil spill accidents and increasing industrial oily waste water. Here, we demonstrate for the first time underwater superoleophobic palygorskite coated meshes, which were fabricated by spraying palygorskite and polyurethane mixtures on copper mesh substrates. The underwater superoleophobic meshes were then used to study gravity driven oil/water separation for a series of oil/water mixtures, where only the water from the oil/water mixture is allowed to permeate through the mesh. A separation efficiency of up to 99.6% could be achieved through the coated mesh for the kerosene–water mixture. In addition, the palygorskite coated mesh still maintained a high separation efficiency of over 99.0% and stable recyclability after 50 separation cycles with the surface morphology of the palygorskite coated mesh nearly unchanged. Furthermore, the palygorskite coated meshes exhibit excellent environmental stability under a series of harsh conditions, which are used for the separation of mixtures of oil and various corrosive and active aqueous solutions, including strong acidic, alkaline, or salt aqueous solutions, even hot water. The fabrication approach presented here can be applied for coating large surface areas and to develop a large-scale oil/water separation facility for oil and various corrosive and active aqueous mixtures.

Facile fabrication of an underwater superoleophobic mesh for effective separation of oil/simulated seawater mixtures

Recently, oil/water separation has become a global challenge due to frequent oil spills. Herein, we demonstrate an underwater superoleophobic Ag coated mesh, which is fabricated by a facile galvanic exchange reaction. The mesh was used to study gravity-driven oil/simulated seawater separation, in which a separation efficiency of above 94.0% could be achieved. In addition, the Ag coated mesh can maintain this high separation efficiency after 45 separation cycles. Furthermore, the Ag coated mesh exhibits excellent environmental stability under harsh conditions. We believe that the Ag coated mesh can be applied for the development of functional materials for oil/water separation.

Selective no loss transportation of water droplets based on the superhydrophobic surfaces with controllable high water adhesion

Abstract Superhydrophobic ZnO surfaces with controllable high water adhesion have been fabricated by combining both construction of ZnO structures on zinc substrates and the subsequent modification of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PDTMS). Different surface morphologies were obtained on the zinc substrates by changing the concentration ratio of (NH4)2S2O8/NaOH and temperature during the hydrothermal process. After being modified with PDTMS, the as-prepared surfaces show analogous superhydrophobicity but controllable high water adhesion, which ranges from 3 to 5 μL, 8 and 10 μL. Based on the different high water adhesion on the superhydrophobic surfaces, the selective no loss water transportation with different volumes has been achieved. We believed that the results reported here would be potentially used in microfluidic systems to manipulate the liquid droplets.