Phthalocyanine- Engineered Functional Membranes for Advanced Water Treatment: Photodynamic Bioremediation and Microplastic Filtration

Abstract

Ensuring access to clean and safe water remains a global priority, yet conventional wastewater treatment plants face increasing challenges in effectively removing microplastics and microbial contaminants, including bacteria and viruses. These pollutants pose significant public health and environmental risks, with microplastics acting as carriers for pathogens and toxic chemicals, exacerbating contamination. Conventional physical, chemical, and biological treatments often fail to address biofouling, antimicrobial resistance, and secondary pollution. Additionally, disinfection techniques such as chlorination and ozonation can generate harmful byproducts, while membrane filtration systems suffer from fouling and limited long-term stability.
To overcome these limitations, material science-driven innovations in membrane technology are essential. Catalytic membrane reactors integrate separation and reaction processes to enhance contaminant removal, yet they often suffer from fouling, limited catalytic efficiency, and gradual deactivation. Photocatalytic membrane reactors address some of these challenges by enabling self-cleaning, energy-efficient pollutant degradation, and microbial inactivation. However, traditional photocatalysts suffer from poor visible-light absorption, rapid charge recombination, and potential toxicity. Photosensitizers offer a superior alternative with broader visible-light absorption, high photostability, and tunable chemistry, allowing seamless integration into polymeric membranes to create a fully organic, scalable, and sustainable platform for filtration and microbial photodynamic inactivation. Among photosensitizers, phthalocyanines have emerged as highly effective antimicrobial and antiviral agents, generating reactive oxygen species under visible-light irradiation, inducing oxidative stress, and disrupting microbial membranes and viral capsids, making them highly effective for bioremediation.
This thesis explores the development of Phthalocyanine-engineered functional membranes as a multifunctional platform for microplastic filtration, photodynamic bioremediation, and biofouling control. Performance evaluation under filtration conditions revealed complete rejection of pristine microplastics (100%) and near-complete removal of biofouled microplastics (99.97%). The membranes also achieved 99.87% E. coli rejection, with a corresponding log reduction value (LRV) of 3.06, and a 2.46-log reduction of Influenza A virus. Furthermore, a 99.8% permeance recovery was recorded under visible light irradiation, indicating excellent fouling reversibility. These findings establish Phthalocyanine-functionalized membranes as a high-performance solution for advanced water treatment, integrating efficient contaminant rejection, biofouling mitigation, and broad-spectrum antimicrobial activity within a single multifunctional platform.

Date of Award	2025
Original language	American English
Supervisor	Srinivas Mettu (Supervisor)