TEPA-SiO2@PDA composite as a highly stable underwater oleophobic coating on copper mesh for oil-water separation with high flux

Abstract

Specially wettable mesh can effectively separate the oil-water mixture. However, the pore blocking and poor stability limit the application. In this work, a tetraethylenepentamine-silica@polydopamine (TEPA-SiO2@PDA) coating is developed on the copper mesh for oil-water separation. By exploiting the rough structure and hydrophilic molecule, an underwater oleophobic surface is obtained, in which the aforementioned challenges can be addressed. As a result, the TEPA-SiO2@PDA modified mesh presents a high underwater oil contact angle and stability at various pH and temperature. Oil-water separation test confirms the high efficiency (>99 %) and high water flux. After 15 cycles of separation testing, it still exhibits a high efficiency of 98.21 % and water flux of 23,315.2 L m−2 h−1. High intrusion pressure and special rough structure contribute to the good oil-water separation ability and high stability. This work proposed a novel strategy for designing a highly stable underwater oleophobic mesh for oil-water separation.