Durable superhydrophobic engineered mesh with self-healing and anti-corrosive capabilities for efficient oil/water separation

Abstract

The complex composition of oilfield-produced water is easy to scratch or corrode the separation membrane because of the existence of solid micro-particles, corrosive acid and alkali, proposing higher requirements on the durability of the membrane. Herein, a durable self-healing stainless-steel mesh was fabricated by hydrothermal growth of Ni and Fe double hydroxide nanosheet structure and dip-coating of polydimethylsiloxane (PDMS). The coating of ultrathin PDMS on the top of the nanosheets excellently maintained roughness of surface, while the PDMS stored at the valleys of the nanosheets array acted as a supplementary source for continuous self-healing process. Therefore, the engineered mesh could self-heal its superhydrophobicity despite suffering from different scales of damage. Moreover, the prepared mesh exhibited reliable superhydrophobicity, mechanochemical durability, corrosion resistance and self-cleaning properties. Eventually, the mesh showed ultrafast flux (21,000 L m−2 h−1) and rejection rate (> 99.99%) for separating phenixin/water mixtures during 50 continuous cycles. In addition to low-viscosity oils, the engineered mesh could separate high-viscosity crude oil/water mixtures. Aiming at the practical problem that dirty oil containing solid micro-particles is difficult to separate, the three-phase separation performance of the mesh on oil/water/sand mixtures was studied. These features make the engineered mesh have great practical application potential in oilfield-produced water treatment.