Efficient Solar-Thermal Distillation Desalination Device by Light Absorptive Carbon Composite Porous Foam

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Solar-thermal desalination using porous carbon materials shows potential for freshwater production.
• Existing high-efficiency solar desalination devices face challenges in practical application, including complex fabrication, cost, and scalability.

Purpose of the Study:

• To introduce facilely fabricated, scalable, and cost-effective direct solar-thermal carbon distillation (DS-CD) tubular devices.
• To evaluate the performance of DS-CD devices in solar still and membrane distillation systems.

Main Methods:

• Fabrication of DS-CD tubular devices using microporous graphite foam coated with carbon nanoparticles and superhydrophobic materials.
• Evaluation of device efficiency in two proof-of-principle distillation systems: solar still and membrane distillation.
• Assessment of solar energy absorbance, solar-steam generation efficiency, vapor production, and salt rejection.

Main Results:

• The solar still configuration achieved a solar-steam generation efficiency of 64% from simulated seawater under 1 sun irradiation.
• The membrane distillation system demonstrated high vapor production (≈6.6 kg m⁻² h⁻¹) with over 99.5% salt rejection under 3 sun irradiation.
• The "black" composite foam effectively absorbs solar light, heating saltwater and producing vapor, while the superhydrophobic surface retains the liquid feed.

Conclusions:

• The developed DS-CD tubular devices offer a scalable and cost-effective approach to solar-energy-driven desalination.
• The adaptable DS-CD technology can be scaled up to high-temperature tubular modules, presenting a viable solution for practical freshwater production.
• These findings address key limitations of traditional solar desalination, paving the way for wider application.