Abstract: A specially functionalized composite filter material with a high specific surface area is used to adsorb PFAs from potable water. In a preferred embodiment, the base filter material is granular activated carbon (GAC), which is sequentially coated with a thin layer of polydopamine, a thin layer of partially oxidized iron, and a thin coating of octadecylamine. After PFAs are adsorbed onto the coated GAC particles, the PFAs are removed by a rinsing process, and remain in the rinse effluent. GAC particles are recovered and recoated as needed to restore their adsorptive capacity. The PFA-containing effluent is treated using photochemical processes to destroy the PFA molecules. The now PFA-free effluent can be disposed of as a non-hazardous material. The composite filter material works in systems ranging from small passive systems for personal use to large scale, high-flow-rate utility water treatment systems.

Abstract: Described here is a free-standing composite particle with a large surface area. The particle is capable of adsorbing heavy metal contaminants from water. The particle itself is comprised of a granular activated carbon particle to which are attached one or more carbon nanotubes, the combination of which is covered by at least a partial thin film of polydopamine or other polymeric material derived from dopamine-like compounds. The composite particles are mixed with contaminated water, after which the water and particle mixture is injected into a hydrocyclone separator specifically designed for use with the composite particle. The hydrocyclone separator removes the particles from the water, allowing the particles holding the contaminants to be extracted for treatment, while the purified water flows out of the separator for reuse. The separated particles can be treated to remove all the adsorbed contaminants, after which the reclaimed particles may be reused.