Method for Purifying Water Contaminated with Environmental Chemicals

Technical Summary:

Bismuth phosphate (BiPO4) has been explored previously as a photocatalyst for advanced oxidation of organic contaminants. This method applies BiPO4, in microparticle form, as a suspension in water and reducing conditions are established in order to reduce, rather than oxidize, target contaminants - particularly recalcitrant poly/perfluoroalkyl substances. Reduction conditions are created by purging out dissolved oxygen via nitrogen bubbling, and through addition of an organic electron donor, such as methanol. The anoxic water and catalyst mixture is irradiated with ultraviolet lamps inside a photoreactor to induce treatment. Subsequently, the catalyst particles may be removed and recycled using a membrane separation process. The key aspect of the claims of this invention is the combination of BiPO4 and reducing conditions to induce treatment of PFAS, which has not been similarly demonstrated previously.