Large-Scale Flat Silk Cocoons as a Highly Effective Salt-Resistant Low-Cost Solar-Powered Evaporator

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Solar seawater evaporation is crucial for freshwater production but faces challenges in efficiency, salt resistance, and scalable manufacturing.
• Existing evaporative materials struggle with performance limitations and high production costs.

Purpose of the Study:

• To develop a novel, cost-effective, and highly efficient solar seawater evaporator using modified flat silk cocoons.
• To investigate the performance of a Janus-structured evaporator (FJE) in terms of evaporation rate, salt resistance, and thermal localization.

Main Methods:

• Large-sized flat silk cocoons (FSC) were produced and modified into a Janus-structured evaporator (FJE) with superhydrophobic (polydimethylsiloxane) and superhydrophilic (polypyrrole) layers.
• The FJE's water transport, heat localization, and evaporation performance were evaluated under solar irradiation using saline solutions.

Main Results:

• The FJE achieved a high evaporation rate of 3.075 kg m⁻² h⁻¹ and an impressive efficiency of 79.73%.
• Exceptional salt resistance was demonstrated, with sustained evaporation for 18 hours in 20 wt.% saline solutions without salt deposition.
• The FJE exhibited excellent cost-effectiveness (258.2 g h⁻¹ USD⁻¹) and efficient solar energy utilization.

Conclusions:

• The Janus-structured evaporator based on flat silk cocoons offers a promising new generation of eco-friendly, cost-effective, and high-performance solar desalination technology.
• The unique Janus structure facilitates efficient water transport and evaporation while preventing salt precipitation, addressing key challenges in solar seawater desalination.