A durable efficient oil–water separation material: Polydopamine coating on modified stainless steel mesh

With the growing contamination of oily wastewater, there is a pressing need to identify a material capable of effectively promoting the separation of oil–water mixtures. Although a large number of materials were applied to the oil–water separation, there are few materials can be applicable for a wide range of oily wastewater, and the separation of oily wastewater with complicated oil and water contents is still a challenge. In this study, the stainless steel mesh (SSM) was modified by the (NH 4 ) 2 S 2 O 8 /NaOH mixed solution and oxalic acid solution subsequently, then, a micro-thin layer of polydopamine (PDA) was deposited on the modified SSM (PCO-SSM). Results indicated that the PCO-SSM was superhydrophilic/underwater superoleophobic and exhibited excellent anti-pollution property. The PCO-SSM can efficiently separate a wide range of oil–water mixtures, such as oily wastewaters from kitchen oils, industrial oils and organic solvents. Furthermore, for the oily wastewater with complicated oil compositions and waters at different harsh conditions, the PCO-SSM can also separate them with a high water flux (10 4 –10 5  L m −2  h −1 ) and separation efficiency (＞99.0 % for most of cases). The excellent separation performance of the PCO-SSM provides a eurytopic material for oil–water separation.