Removal of Per-and Polyfluoroalkyl Substances from Water using Ti-MOFs

A. Boehme, R. Ozdemir
United States

Keywords: water safety, per- and polyfluoroalkyl substances, metal organic frameworks


Due to high regulations of Per-and Polyfluoroalkyl Substances (PFAS) in drinking water from the Safe Water Drinking Act, greater attention is being paid to the dangers of such substances to human health. framergy’s recent studies have shown that the application of its sorbent, AYRSORBTM T125 (MIL-125-NH2), can stimulate the removal of these compounds from water. AYRSORB T125 demonstrated not only excellent PFAS capture, but also showed photocatalytic degradation paving the way to prevent the bioaccumulation of these compounds. Per- and polyfluoroalkyl substances have increasingly been used in the chemical industry due to their hydrophobic chains. Amongst PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been of tremendous interest due to their large variety of uses, such as food production, non-stick cookware, cleaning products, water- repellant fabrics, and commodity synthesis and fabrication. However, due to their environmental persistence, toxicity, and global use their remediation has gained increasing importance. Already there is are significant levels of PFOA and PFOS contamination in drinking water caused by localized contamination. Processes such as anion exchange, reverse osmosis, microfiltration, granular filtration, sorption, and flocculation have all been found ineffective at removing PFAS from drinking water. To address the growing environmental concerns surrounding persistent PFAS contamination, novel remediation methods, combining the strengths of multiple strategies, are urgently needed. AYRSORBTM T125, a metal organic framework, consists of titanium-oxo clusters bridged with 2-aminoterephthalic acid. Both of these components have been found to be effective in photocatalytic PFAS degradation. First, the titanium-oxo clusters are known to act as analogues to titanium dioxide, facilitating photocatalysis. Second, the incorporation of the amino functional group into 2-aminoterephthalic acid has been observed to help shift the absorption band of the material from the ultraviolet (UV) to the visible region, with AYRSORB T125 showing a clear absorption in the visible 400-425 nm range due to this effect. Initial photocatalytic degradation studies were performed using PFOS in an aqueous solution with triethanolamine (TEOA) as a sacrificial reductant. The results show that AYRSORB T125 is capable of degrading PFOS. The data represents the first known example of photoactive degradation of PFAS using Metal-organic Frameworks (MOFs). To further develop this promising technology, framergy, Inc. is currently developing a novel water pretreatment system, which combines the use of this cutting-edge nanostructured sorbent for the effective removal of PFAS by leveraging its highly selective adsorption and photocatalytic properties. At the heart of this technology are the innovative, chemically stable MOFs, which can be tailored for selective PFAS and PFOS capture and breakdown under UV or sunlight. framergy is a startup nanomaterial company, which designs and manufactures coordination polymers, including MOFs. Founded in 2011, framergy is the oldest coordination polymer company in the world. While there are many university MOF driven startups, framergy is the only Company in the material class with investments from industrial companies commercializing MOFs at scale.