Black Titanium Dioxide/Calcium Alginate Composite Hydrogel for Efficient Solar-Driven Interfacial Evaporation

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Solar-driven interface evaporation (SDIE) is crucial for addressing global water scarcity.
• Developing stable, high-performance photothermal materials is key to advancing SDIE technology.
• Black titanium dioxide (TiO2) offers excellent light absorption and chemical stability for SDIE applications.

Purpose of the Study:

• To develop a novel black TiO2-based composite hydrogel for efficient solar-driven interface evaporation.
• To evaluate the performance of the composite hydrogel under various conditions, including high salinity.
• To demonstrate the material's potential for practical seawater desalination.

Main Methods:

• Preparation of black TiO2 nanoparticles via precursor calcination.
• Fabrication of a black TiO2/calcium alginate composite hydrogel (PUCA-TiO2) using a polyurethane sponge backbone.
• Characterization of the evaporator's performance, including evaporation rate and photothermal conversion efficiency under simulated solar irradiation.

Main Results:

• The PUCA-TiO2 evaporator achieved an evaporation rate of 3.331 kg m-2 h-1 and 92.79% photothermal conversion efficiency at 1 kW m-2 solar intensity.
• The material maintained an efficient evaporation rate of 2.876 kg m-2 h-1 in 25 wt% brine.
• Seawater desalination tests confirmed excellent capacity and long-term salt stability.

Conclusions:

• The developed PUCA-TiO2 composite hydrogel overcomes limitations of traditional TiO2 photothermal materials.
• This material demonstrates significant potential for efficient and stable solar interface evaporation applications.
• The study highlights a promising advancement in materials for addressing water resource challenges.