Research Projects

This proposal aims to address the pressing technological challenge of water contamination by per- and polyfluoroalkyl substances (PFAS)—a group of synthetic, highly persistent, and toxic micropollutants. Known as “forever chemicals” due to their resistance to degradation, PFAS pose significant threats to water security and public health globally, including in India. Due to the high chemical stability of the C-F bond, these chemicals are resistant to photo-, thermal, and biological degradation and even advanced oxidation processes, which is the reason for their wide application in firefighting foams, metal finishing, and packaging industries. Regulatory benchmarks highlight their toxicity: the U.S. EPA recently lowered the recommended drinking water limit for PFOA and PFOS to just 4 ng/L (from 70 ng/L), while the EU has set a combined threshold of 100 ng/L. Alarming levels of PFAS contamination have been detected in major Indian water bodies, including the Ganges River and groundwater in Chennai, with concentrations ranging from 0.10 ng/L to over 130 ng/L. While many countries have begun regulating these harmful substances, India still lacks clear and enforceable guidelines, highlighting the urgent need for action. Recently, covalent organic frameworks (COF)-modified membranes have emerged as a highly promising technology for sustainable water purification, particularly for treating PFAS-contaminated water. These are increasingly being adopted as an alternative to state-of-the-art technologies for PFAS removal, including granular activated carbon (GAC), ion exchange (IEX) resins, and high-pressure membranes such as nanofiltration (NF). PFAS-loaded ion exchange resins are typically non-regenerable, while activated carbon requires specialized facilities for high-temperature regeneration and exhaust gas treatment. Nanofiltration is gaining traction, but produces concentrated retentate that cannot be safely released into the environment. Additionally, high-pressure membranes often remove essential mineral ions and involve higher complexity and costs. In response to these limitations, this project aims to develop a novel class of COF-based membranes designed for adsorption-enhanced ultrafiltration (UF) to efficiently remove PFAS from water. COF materials such as TpPa, COF-300, TpBD, and COF-5 will be integrated into membranes as nanoparticle layers to maximize contact with contaminated water while preserving membrane permeability. To prevent leaching and ensure stability, a polymeric hydrogel matrix—synthesized in situ via graft polymerization—will entrap the COF nanoparticles on the membrane surface. The project will specifically target highly mobile PFAS, including long- and short-chain PFAS, as well as emerging alternatives like GenX, ADONA, and PFPeA. This new approach minimizes waste production, retains essential minerals, and supports circular economy and zero-pollution principles.