Full-Spectrum Carbon-Based Ceramic Fibers and Their Application in Seawater Desalination

Abstract

[Introduction] An environmentally friendly technology that harnesses green renewable solar energy to generate thermal energy for seawater desalination is proposed and the design of a novel fibrous membrane evaporator with full-spectrum absorption capability is introduced, aiming to address global challenges such as environmental pollution and freshwater scarcity. [Method] The proposed technological process began with the preparation of nano-scale C@TiO2 fibrous membranes using the electrospinning process. These membranes then underwent in-situ carbothermal reduction at 800 ℃ for 2 hours, resulting in the production of carbon-based ceramic C@Ti4O7 photothermal conversion materials with a dark color. [Result] The results show that the C@Ti4O7 fibrous membrane exhibits a band gap much lower than that of W-TiO2 and excellent solar light absorption capability across a wide range of wavelengths from 200 to 2500 nm, due to the doping of C elements and Ti3+ and the presence of oxygen vacancy defects. Under a light intensity of 1 kW/m2, the surface temperature of the C@Ti4O7 fibrous membrane, floating at the air-seawater interface, can quickly rise to 74.55 °C. Consequently, the evaporation rate of seawater increases to 1.55 kg/(m2·h), resulting in a photothermal conversion efficiency as high as 90.68%. With a light intensity of 5 kW/m2, the evaporator can generate electrical signals of up to 460 mV. In addition, it is proven workable continuously for 30 days in the simulated seawater with NaCl mass fraction of 10%, without salt deposition on the surface. [Conclusion] Therefore, the adoption of carbon-based ceramic C@Ti4O7 as the photothermal conversion material for the solar-driven interfacial evaporator offers not only high efficiency in photothermal conversion, but also great potential for large-scale applications, demonstrating a broad application prospect in the field of seawater desalination.

Keywords

• interfacial evaporation
• photothermal conversion
• ti4o7
• seawater desalination
• hydroelectric power generation