Surface Roughness Engineering for High-Salt-Tolerant Solar Evaporator with Enhanced Efficiency in Sustainable...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Dense salt crystal accumulation on solar evaporators reduces efficiency by blocking light and water flow.
• Preventing salt adhesion is crucial for sustained high performance in solar evaporation.

Purpose of the Study:

• To develop a novel solar evaporator that mitigates salt crystallization issues.
• To enhance water evaporation rates using a modified wood-based material.

Main Methods:

• Coating delignified wood (DW) with KOH-activated carbon (KAC) to create a 3D column-shaped evaporator (KAC-DW).
• Characterizing the microstructured surface of the KAC coating for protrusions.
• Testing the KAC-DW evaporator's performance under simulated solar radiation with saline solutions.

Main Results:

• The KAC-DW evaporator exhibited microstructured protrusions (≈144 mm⁻², 20 μm height) that inhibited salt adhesion.
• Achieved a water evaporation rate of 8.18 kg m⁻² h⁻¹ with 15 wt% NaCl solution, over double that of uncoated DW (3.91 kg m⁻² h⁻¹).
• Sustained high performance over 96 hours due to prevented dense salt layer formation and promoted loose crystal growth.

Conclusions:

• The KAC coating effectively prevents salt accumulation on solar evaporators.
• The engineered surface enhances solar evaporation efficiency through improved light absorption and water transport.
• This KAC-DW material offers a promising solution for efficient solar water desalination.