Simple carbonization of sorghum straw: A Janus structure for highly efficient solar interface water evaporation

Solar interfacial evaporation is a green, environmental-friendly, energy-saving technology for clean water production. Designing a solar evaporator with a special structure is a feasible way to enhance the effect of light and heat. However, low efficiency, high cost and complicated manufacturing of solar evaporator are still its key problems. Biomass-based materials, with their unique natural structure, good environmental friendliness and low cost, have attracted extensive research interest as solar energy absorbing materials. In this paper, the cheap biomass sorghum straw (SS) is used as the material, and the dehydrated carbonation property of sulfuric acid is used to make the top of sorghum straw form a carbonation layer, and this carbonation layer forms a special –bowl-like structure, which increases the reflection of the incident light and the capture of the light, so that the sorghum straw solar energy evaporator's light absorption rate is more than 90 %, the evaporation rate is as high as 1.96 kg m −2  h −1 under one solar radiation, and the evaporation efficiency is 81.8 %. Notably, CSS demonstrated remarkable cyclic stability, along with excellent desalination and purification performances. This research offers a practical approach for the efficient utilization of sorghum straw, thereby holding substantial research significance and practical application potential.