1. Field of the Invention
This invention relates generally to a novel polymer material and, more specifically, to a styrene-divinylbenzene three-dimensional copolymer having two different functional groups bonded directly to at least portion of the benzene nuclei of the copolymer and useful as a nitrate ion adsorbent.
2. Description of Prior Art
Known nitrate ion adsorbents include a graphite-nitric acid intercalated compound (Japanese Published Examined Patent Application No. Sho-60-18605) and an anion ion exchange resin having tributylamino groups (U.S. Pat. No. 4,479,877). The former adsorbent has a disadvantage because the absorption and desorption rates are not high. The latter, anion resin adsorbent has a drawback that it is difficult to regenerate the used adsorbent, although the selectivity thereof to nitrate ion is high.