Nanotechnology Products and Applications
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Product Sector: Food → Food Processing → Filtration
Pleated filter cartridges combining high efficiency particulate filtration with a high efficiency (powdered) activated carbon (PAC) into a single depth media - NanoCeram-PAC is a further advancement in Argonide's series of filters and is a major breakthrough in using activated carbon for purifying water.
Typically granular activated carbon (GAC) is used in a packed bed or is combined into a media using adhesives or via a foamed polymer. What is new with NanoCeram-PAC is that fine activated carbon powder (-325 mesh) is held within the structure by electro-adhesive forces, without using adhesives that would blind or deactivate the carbon. As compared to media containing GAC, PAC offers a much greater external surface area that results in much more rapid adsorption of soluble contaminants. Contaminants removed include chlorine, iodine or soluble organics that may be highly toxic or may cause unpalatable taste and odor. The result is much greater adsorption efficiency at moderate to high flow rates and/or with thin beds of media, such as a single layer pleated cartridge. At the same time, the media is capable of retaining bacteria, virus and colloidal particles with efficiency that is unsurpassed as compared to a depth media, a microporous membrane or even an ultraporous membrane.
How it works
Nano alumina is combined into a microglass fiber matrix to form an electropositive (~+50 mV) filter media and is then converted into pleated cartridges. The active ingredient is a nano alumina fiber that is only 2 nanometers in diameter and about 250 nm long and is grafted to a microglass fiber backbone. Coarser cellulose or synthetic polymer fibers are added to enlarge the pore size and provide flexibility and strength. The media is produced by a conventional wet laying process and is then pleated and end-capped to form a cartridge. Since virtually all small particles are electronegative in water, they are readily adsorbed. This filter has a high efficiency for capturing very fine particles. What we discovered is that we could add very fine or even nano size particles in fabrication of the paper-like sheet, and that they are held so tightly that they can't be removed without destruction of the media or by other heroic means. The first commercial implementation contains 32 weight percent of a high surface area commercial PAC (Iodine Number=1100 mg/g, ave.particle size ~27 µm). The new media is laminated with polyester spun-bond. Its pore size is 2 µm and its flowrate is equivalent to NanoCeramŽ cartridges.