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Chemical removal of nitrate from water


HIGH levels of nitrate in ground water can pose a serious health risk. Reduction of nitrate to nitrite in the gut may cause methemoglobinaemia1both in newborn infants and in adults deficient in glucose-phosphate dehydrogenase2. Under abnormal circumstances, reduction to nitrite can also occur in the stomach to form N-nitrosamines, a postulated cause of stomach cancer3. Nitrate outflow onto shallow continental shelves can promote nearshore algal blooms. Both natural and anthropogenic sources contribute to nitrate pollution. In the United States4 and Europe5, legislation now specifies a maximum permissible nitrate level in drinking water. Techniques such as selective ion exchange6, reverse osmosis, electrodialysis and distillation exist to transfer nitrate between two bodies of water, but only biological processes are presently available for nitrate destruction. Here I describe a chemical process in which aluminium powder reduces nitrate to ammonia, nitrogen and nitrite. In a pH range of 9 to 10.5, selective reduction of nitrate relative to sulphate is possible, and between pH 9.1 and 9.3, loss of the reductant through decomposition of water can be minimized to less than 2%. Subsequent control of pH and concentrations of dissolved aluminium, nitrite and ammonia should be possible at a realistic cost, making this process potentially useful for combating nitrate pollution.

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  1. Walton, G. Am. J. Public Health 41, 986–995 (1951).

    CAS  Article  Google Scholar 

  2. Challis, B. C. Nature 244, 466 (1973).

    ADS  CAS  Article  Google Scholar 

  3. Mirvish, S. Nature 315, 461–462 (1985).

    ADS  CAS  Article  Google Scholar 

  4. U.S. Congress 93, Session 433 Safe Drinking Water Act Public Law 93-523 (1974).

  5. Eur. Chem. Industry Ecol. Toxicol. Centre Tech. Report No. 27 (Brussels, Belgium, 1988).

  6. Hoek, J. P. van der et al. Wat. Air & Soil Pollut. 37, 41–53 (1988).

    ADS  Article  Google Scholar 

  7. Weast, R. C. (ed.) Handbook of Chemistry and Physics 65 edn, D155–D158 (Chemical Rubber Company, Boca Raton, 1976).

  8. Murphy, A. P. U.S. Patent applied for August 1990.

  9. Pontius, F. W. (eds) Water Quality and Treatment 4th edn, 168 (McGraw-Hill, New York, 1990).

  10. Mioduszewski, D. Wat. & Wastes Engng 12, 34–46 (1975).

    CAS  Google Scholar 

  11. Wolfe, R. L. et al. J. Am. Water Works Assoc. 76, 74 (1984).

    ADS  CAS  Article  Google Scholar 

  12. Pressley, T. A. et al. Envir. Sci. Technol. 6, 622 (1972).

    ADS  CAS  Article  Google Scholar 

  13. Diyamandoglu, V. et al. Envir. Sci. Technol. 24, 1711 (1990).

    ADS  CAS  Article  Google Scholar 

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Murphy, A. Chemical removal of nitrate from water. Nature 350, 223–225 (1991).

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