Recyclable superhydrophilic meshes with scalable and robust coating for separating oily wastewater

[Display omitted] •The mesh showed reliable superhydrophilicity, mechanical durability, ultra-high separation fluxes and rejections for separating oily wastewater.•A strategy of scalable and robust hydrophilic modification was successfully developed by uniformly oxidizing and then coating tough sodium alginate/phytic acid hydrogel with the hydrogen-bonded-ionic double network.•This developed mesh with recyclability and durability is promising for low-cost, large-scale and long-term treatment of oily wastewater. Oily wastewater, mainly from the petroleum related industries, have posed on extremely serious waste of water resources and oil resources. Superwetting membrane technology is considered to be the most effective method to treat oily wastewater. And a scalable strategy to prepare robust superhydrophilic membrane is the core issue. In this work, a superhydrophilic mesh was successfully prepared via facile oxidation and coating strategy. The oxidative treatment successfully fabricated large-scale uniform hierarchical morphologies on mesh. And the coating of sodium alginate/phytic acid hydrogel on the hierarchical mesh synthesized tough and controllable superhydrophilic layer, based the hydrogen-bonded-ionic double-network design. This developed mesh was superhydrophilic, underwater superoleophobic (∼171°) and antifouling. And this mesh also possessed strong mechanical durability, excellent chemical durability, ultra-high separation fluxes (28,220–54,340 L·m−2·h−1) and rejections (99.99%) for separating oily wastewater. In addition, with the assistance of calcination, this mesh could be recyclable. This developed mesh with recyclability and scalability looks promising for low-cost, large-scale and long-term treatment of oily wastewater.