Water filtration method

Abstract

A drinking water filter for removing lead at point-of-use composed of specially treated gamma alumina particles between 48 and 100 mesh (0.148-0.297 mm), gamma alumina neutral (about 7 surface pH) or basic (about 9 surface pH) is washed in highly purified H.sub.2 O at 100.degree. C. to reduce alumima surface pH to 3.5-5.0 and then washed with highly purified H.sub.2 O at ambient temperature. The alumina is placed for three to twelve hours in bath having equivalent pH value (3.5-5.0) of acid electrolyte, diluted with a highly purified H.sub.2 O, preferably HCl, ascorbic acid or EDTA, adjusted to alumina surface pH level and desired degree of dilution by salts such as NaCl and/or alkalies such as NaOH to transfer to adsorbent surface materials that effect selective ion exchange with lead and other heavy metal ions or otherwise cause their removal from drinking water. Upon removal of alumina from bath, it is vacuum washed and then dried in an oven at 200.degree. C. to 350.degree. C. for about two hours. For wet packing in cartridges about 50%, and for dry packing about 98% of moisture is so removed Cartridges contain about 200 grams alumina for each one-half gallon capacity flow per minute, the treated alumina being tightly packed in the cartridges to prevent channeling while not causing a pressure drop at maximum rated capacity of more than about 10 psi across the cartridge. The filter is placed after a further filter using shavings of a zinc-copper alloy to remove chlorine and nitrates, the alumina filter removing zinc, copper, and other heavy metals leached from the zinc-copper alloy media.

Dependencies are inferred from the claim text.