Design of Pickering Emulsions for Photocatalytic Applications

Abstract

Modern wastewater is full of organic pollutants — from pesticides to pharmaceuticals — that are difficult to remove with traditional treatment methods. This PhD research addresses that challenge with a creative solution: using sunlight and carefully engineered oil droplets, stabilized by light-activated particles, to break down harmful chemicals in water.

These droplets, known as photocatalytic Pickering emulsions, act like tiny chemical microreactors. They are stabilized by nanoparticles, such as titanium dioxide (TiO₂), that sit at the oil-water interface. There, they absorb sunlight and trigger reactions that break down harmful organic pollutants.

The thesis explored how to fine-tune these emulsions to make them more effective, stable, and reusable:

· Embedding TiO₂ into hydrogels created more robust droplets that could be reused without losing performance.

· Coating TiO₂ particles with polymeric stabilizers like poloxamers helped resist changes in water chemistry but could slightly reduce cleaning efficiency.

· Particle surface modifications using silane chemistry allowed better control over droplet formation and pollutant interaction.

· Gold-doped titania particles improved light absorption and performance — especially under visible light — while also enhancing droplet stability.

This thesis not only expands the science of photocatalytic emulsions but also kickstarts new ways of thinking about sustainable water treatment. It shows that combining photocatalysis with smart material design can overcome long-standing challenges in the field — offering a low-cost, reusable, and scalable approach to cleaning contaminated water.