Insight into the Charge-Ratio-Tuned Solar Vapor Generation of Polyion Complex Hydrogel/Coal Powder Composites

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Solar-driven water purification is crucial for addressing global water scarcity.
• Traditional solar distillers face limitations due to low evaporation rates and high material costs.
• Developing efficient and cost-effective photothermal materials is essential for practical solar water purification.

Purpose of the Study:

• To develop a highly efficient solar distiller using a novel polyion complex hydrogel/coal powder composite (HCC).
• To investigate the impact of charge ratio on the solar vapor generation performance of HCC.
• To evaluate the purification capabilities of HCC for various water bodies.

Main Methods:

• Fabrication of polyion complex hydrogel/coal powder composite (HCC) via polyelectrolyte complexation.
• Systematic investigation of the charge ratio of polyanion-to-polycation on HCC performance.
• Characterization using scanning electron microscopy (SEM) and Raman spectroscopy.
• Performance evaluation under one sun irradiation for solar vapor generation (SVG) and water purification.

Main Results:

• HCC prepared at the charge balance point exhibited the highest evaporation rate (3.12 kg m⁻² h⁻¹) and solar-vapor conversion efficiency (88.83%).
• Deviation from charge balance negatively impacted microporous structure, water transport, and water molecule activation.
• HCC demonstrated high evaporation rates for simulated seawater (3.22 kg m⁻² h⁻¹), acid (2.98 kg m⁻² h⁻¹), and alkaline (2.85 kg m⁻² h⁻¹) solutions.

Conclusions:

• The study presents a low-cost, highly efficient solar distiller based on HCC.
• Optimizing the charge ratio is critical for maximizing solar vapor generation performance.
• HCC shows significant promise for practical applications in seawater desalination and industrial wastewater purification.