Preparation of biochar-based photothermal superhydrophobic coating based on corn straw biogas residue and blade anti-icing performance by wind tunnel test

The utilization of biological resources is conducive to alleviating energy shortages and environmental pollution, and the application of biochar to anti-icing can promote green low-carbon cycle development. In this study, the ice-phobic coating with a photothermal effect was prepared from biogas residue after anaerobic digestion. The modification and Fe3O4 loading promoted the formation of the rough structure of the material and reduced the hydrophilic groups, thus increasing the contact angle of the prepared photothermal coating to 154.49°. The rough structure of the biochar-based photothermal superhydrophobic coating effectively decreased the contact area between the coating and the ice, significantly reducing the icing adhesion strength to 71.96 kPa. The Fe3O4-loaded biochar material had an extremely high light absorption capacity, which rapidly increased the surface temperature of the coating to 48.2 °C. This was attributed to the photothermal properties of the Fe3O4 particles, which enhanced the photothermal conversion performance of the photothermal coating. Icing wind tunnel experiments showed that the maximum reduction in icing mass and icing area of coated blades were 39.13% and 13.48%, respectively, compared to uncoated blades, indicating that the coating had a good anti-icing effect. The biochar-based ice-phobic coating had fine acid and alkali resistance and durability. This study provided a method for anti-icing civil and industrial material surfaces.