Pickering emulsion-embedded hierarchical solid-liquid hydrogel spheres for static and flow photocatalysis

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Pickering emulsion-based photocatalysis offers large surface area and spatial separation for substrate enrichment.
• Hierarchical structures combining Pickering emulsions, hydrogels, and photocatalysts show potential for enhanced degradation.
• Efficient charge separation at interfaces is crucial for improving photocatalytic activity.

Purpose of the Study:

• To develop a novel hierarchical structure for enhanced photocatalytic degradation of 2-naphthol.
• To investigate the role of ionic liquids and graphene oxide/TiO2 interfaces in photodegradation.
• To establish a continuous flow photocatalytic system using the developed material.

Main Methods:

• Preparation of calcium alginate gel spheres encapsulating ionic liquid-in-water Pickering emulsions with TiO2, stabilized by graphene oxide, via emulsion gelation.
• Utilizing simulated solar irradiation for the photodegradation of 2-naphthol.
• Constructing a continuous flow photocatalytic system using the millimeter-sized gel spheres as column fillers.

Main Results:

• The hierarchical structure demonstrated enhanced degradation activity of 2-naphthol into small molecular alkanes.
• The ionic liquid acted as an effective adsorption medium, and the graphene oxide/TiO2 interface facilitated superior charge separation compared to pure TiO2.
• The continuous flow system achieved ~100% removal of 2-naphthol on stream, demonstrating sustained performance.

Conclusions:

• The novel hierarchical photocatalyst effectively degrades 2-naphthol, leveraging Pickering emulsion and hydrogel properties.
• The synergistic effect between ionic liquid adsorption and graphene oxide/TiO2 charge separation significantly boosts photodegradation efficiency.
• The developed material is suitable for constructing robust continuous flow systems for efficient water pollutant removal.