Surface engineering of stainless-steel mesh with superwettability toward efficient water treatment through electroflotation

Abstract

Electroflotation water treatment technology employs bubbles generated by water electrolysis to capture and remove pollutants from wastewater. Effective bubble-pollutant adhesion is essential for high-performance electroflotation, highlighting the importance of bubble regulation. Herein, we report a surface-engineered stainless-steel mesh electrode with underwater superaerophobicity that enables efficient generation of fine bubbles and markedly boosts electroflotation performance. The generation of fine bubbles reduces coverage of catalytic active sites on the structured and superaerophobic stainless-steel mesh electrode engineered by femtosecond laser, thereby improving electrochemical hydrogen evolution activity and operational stability. During electroflotation, these fine bubbles significantly increase the removal efficiency of small pollutants, including emulsified oil droplets and bacteria, by facilitating effective collision and adhesion. Furthermore, we integrate a filtration function by depositing a superoleophobic silica layer on the backside of the electrode, enabling subsequent oil–water separation via filtration. The post-electroflotation effluent exhibits a substantially higher filtration flux, confirming that electroflotation pretreatment effectively mitigates membrane blockage. Overall, the surface-engineered electrode integrates electroflotation and membrane filtration within a single device, providing an energy-efficient strategy for advanced water treatment.