Starch hydrogel with Poly(ionic liquid)s grafted SiO₂ for efficient desalination and wastewater purification

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Freshwater scarcity is a global challenge.
• Solar-driven interfacial evaporation is a sustainable solution.
• Existing photothermal materials face challenges in cost, efficiency, and scalability.

Purpose of the Study:

• To develop a facile and green strategy for preparing an efficient hydrogel evaporator.
• To address the limitations of current photothermal conversion materials.
• To create a durable and scalable solution for water desalination.

Main Methods:

• Grafting poly(ionic liquid)s onto silica nanoparticles.
• Doping the composite with starch to form a hydrogel evaporator (SiO2-PILs/starch).
• Evaluating solar absorption, hydrophilicity, salt tolerance, and evaporation efficiency under simulated solar irradiation.

Main Results:

• The SiO2-PILs/starch hydrogel exhibits broad solar absorption (approx. 91%).
• Achieved high solar evaporation efficiencies: 91.72% for pure water and 81.45% for 20 wt% NaCl solution.
• Demonstrated excellent long-term salt stability (8h), self-cleaning of salt crystals, and 75.84% efficiency in oily wastewater.

Conclusions:

• The developed SiO2-PILs/starch hydrogel is a highly efficient and durable material for solar-driven water evaporation.
• Its properties make it suitable for practical applications in desalination and wastewater treatment.
• This material offers a promising, cost-effective, and scalable solution to freshwater scarcity.