Insights into Localized Crystallization in the 3D-Cone Solar Evaporator for High-Salinity Desalination

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Solar-driven interfacial evaporation is a key technology for desalination.
• Salt deposition on evaporator surfaces hinders continuous operation and efficiency.
• Understanding salt precipitation mechanisms is crucial for advanced evaporator design.

Purpose of the Study:

• To design and investigate a 3D conical cellulose paper evaporator for efficient solar desalination.
• To elucidate the mechanism of controlled salt precipitation in a 3D structure.
• To achieve continuous desalination of high-salinity water with improved salt management.

Main Methods:

• Fabrication of a low-cost, 3D conical evaporator from cellulose paper.
• Investigation of salt diffusion and accumulation rates under solar irradiation.
• Analysis of temperature gradients and surface tension effects on salt precipitation.
• Long-term performance testing with high-salinity water (24.5 wt.%).

Main Results:

• The 3D conical evaporator successfully directed salt precipitation to a specific location (1.4 cm above the base).
• Continuous operation for up to 8 hours was achieved with high-salinity water without performance loss.
• An exceptional evaporation rate of 2.54 kg·m^-2·h^-1 was recorded.
• A high solar energy conversion efficiency of 93.7% was demonstrated.

Conclusions:

• The 3D conical design effectively manages salt crystallization through controlled diffusion and accumulation.
• Temperature-induced surface tension gradients play a vital role in directing salt precipitation.
• This work offers a promising strategy for developing durable and efficient solar desalination systems.