Robust Photocatalytic MICROSCAFS^® with Interconnected Macropores for Sustainable Solar-Driven Water Purification

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Advanced oxidation processes (AOPs) are crucial for degrading organic pollutants in wastewater.
• Photocatalysis, utilizing semiconductor nanoparticles, offers a promising AOP for water remediation.
• Tailored porous materials enhance photocatalyst efficiency and stability for water treatment applications.

Purpose of the Study:

• To investigate the impact of pore and particle size of photocatalytic MICROSCAFS® on methyl orange (MO) degradation.
• To evaluate the performance of photocatalytic MICROSCAFS® in both batch and continuous flow systems.
• To develop a flow kinetic model for simulating photocatalytic MICROSCAFS® performance.

Main Methods:

• Synthesis of silica-titania microspheres (MICROSCAFS®) with controlled porosity and P25 TiO2 nanoparticle grafting via sol-gel and phase separation.
• Photocatalytic degradation experiments of methyl orange (10 mg/L) in aqueous solution using batch and flow reactors under simulated solar light.
• Kinetic modeling, scavenger studies for mechanistic insights, and high-resolution mass spectrometry for transformation product analysis.

Main Results:

• Achieved 87% methyl orange degradation in 2 hours under batch conditions (1 sun simulator, catalyst/pollutant ratio of 23).
• Demonstrated proof of concept for continuous transformation processes using a flow reactor setup.
• Elucidated MO degradation pathways and transformation products, with an in silico toxicity assessment.

Conclusions:

• Photocatalytic MICROSCAFS® show significant potential for efficient organic dye degradation in water.
• The developed flow kinetic model accurately simulates photocatalyst performance in continuous systems.
• Understanding degradation mechanisms and products is vital for assessing the overall environmental viability of the process.