| abstract |
A composite cartridge-type filter effective to substantially reduce low but hazardous concentrations of lead in drinking water to acceptable levels utilizes a porous activated carbon block filter and a powdered deionizing resin which is converted to an ion exchange resin in situ and during use of the filter. The method of operation of the filter results in a substantially extended life for lead removal as compared to similar disposable cartridge filters. The composite filter is also affective in removing dissolved metals which are leached from the soluble ash fraction of the carbon block itself. Powdered deionizing resin, having a greatly enhanced active surface area as compared to the resin beads from which it is formed, is formed by fracturing the resin beads in situ in a slurry filling and drying process which provides a stable packed resin bed. |