Surface Microlenses for Enhanced Photodegradation of Organic Contaminants in Water

Abstract

The global need for clean water requires sustainable technology for purifying contaminated water. Highly efficient solar-driven photodegradation is a sustainable strategy for wastewater treatment. However, solar-driven water treatment suffers from reduced efficiency due to the energy loss in the light treatment, difficulties of facility maintenance, and decentralized and intermittent features of solar irradiation. One promising solution is coupling microlenses (MLs) with solar-driven reactors, optimizing the distribution of solar irradiation in contaminated water for higher photodegradation efficiency of organic contaminants. However, the fabrication of customized MLs for solar-water treatment remains to be developed. Furthermore, understandings of the mechanisms of MLs-enhanced photodegradation are required for the optimization of MLs-involved reactors. Last but not least, the adaptability and scalability of MLs need to be verified before the practical applications of the technology. This Ph.D. thesis focuses on understanding the mechanisms of MLs-enhanced photodegradation in water treatment and maximizing the performance of MLs under the guidance of the discovered principles. On one hand, the fabrication methods of MLs are developed based on a solvent exchange process followed by in-situ photopolymerization to meet the requirements of reactors for solar-driven water decontamination. Both microscopy and optical simulations are applied to characterize the optical properties of different types of MLs. Furthermore, the photodegradation of multiple typical organic pollutants in different water matrices is monitored in the MLs-functionalized reactors under varied irradiation conditions to verify the effectiveness of MLs. The combination of optical simulations and the experimental results helps to further improve the efficiency of solar-driven photodegradation by MLs and assist the design of MLs-functionalized reactors for broader applications.