Facile preparation of photothermal and superhydrophobic melamine sponge for oil/water separation and anti-icing

The preparation of superhydrophobic sponges with excellent physiochemical performance, affordability, and versatility is still a big challenge. Herein, a photothermal and superhydrophobic melamine sponge has been successfully achieved by decorating lignin particles (LPs)@MXene composite onto the skeletons of melamine sponge (MS) via the self-polymerization of dopamine. The obtained superhydrophobic MS (labeled as MS@PDA/LPs@MXene) shows a water contact angle of 153.7°, and maintains surface superhydrophobicity under harsh conditions (i.e., acidic, alkaline environments, high temperatures, frictional damage, and icing/de-icing cycles). Notably, the MS@PDA/LPs@MXene exhibits an exceptional oil adsorption capacity of carbon tetrachloride up to 143.6 times of its own weight, a high separation efficiency of 99.3 %, and a retained separation efficiency of 98.9 % after 15 cyclic adsorption processes, respectively. Owing to a synergistic photothermal effect of PDA and LPs@MXene, the MS@PDA/LPs@MXene possesses a maximum surface temperature of 62.8 °C under solar irradiation (1.0 kW/m2, 1 sun), and realizes the ice-free property at a low temperature of −17.9 °C (relative humidity, 90 %) on a continuous cooling stage under solar irradiation (0.5 sun). Furthermore, the LPs@MXene composite coating can be applied on various substrates (i.e., Al sheet, Cu sheet, filter paper, carbon cloth, steel mesh and NdFeB magnet) to obtain surface superhydrophobicity, showing excellent anti-corrosion property for the permanent NdFeB magnet. Thus, this paper proposes a facile and cost-effective strategy to prepare superhydrophobic melamine sponge with multifunctional properties, and provides new insights into the rational design of high-performance superhydrophobic sponges for their applications in oil/water separation and anti-icing. •A photothermal superhydrophobic melamine sponge (MS) is successfully achieved by decorating lignin particles@MXene composite.•The superhydrophobic MS shows excellent chemical stability, durability, and recyclability in various environments.•The superhydrophobic MS exhibits an oil adsorption capacity of CCl4 up to 143.6 g/g and a separation efficiency of 99.3 %.•The superhydrophobic MS realizes the ice-free property at a low temperature of −17.9 °C under solar irradiation (0.5 sun).•The lignin particles@MXene composite coating can be applied on various substrates to obtain surface superhydrophobicity.