Chemical removal of nitrate from water
Chemical removal of nitrate from water
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DOI：
10.1038/350223a0
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发表时间：
1991-03
期刊：
影响因子：
64.8
通讯作者：
A. P. Murphy
中科院分区：
文献类型：
--
作者：
A. P. Murphy
地下水中高含量的硝酸盐会造成严重的健康风险。硝酸盐在肠道中还原为亚硝酸盐可能会导致高铁血红蛋白血症1，无论是新生儿还是缺乏葡萄糖磷酸酶的成人。在异常情况下，亚硝酸盐也可以在胃中还原形成N-亚硝胺，这是胃癌的一个假定原因3。硝酸盐外流到浅水大陆架上会促进近岸藻类大量繁殖。自然和人为来源都有助于硝酸盐污染。在美国4和欧洲5，立法规定了饮用水中硝酸盐的最高允许含量。现有的技术，如选择性离子交换6、反渗透、电渗析和蒸馏，可在两个水体之间转移硝酸盐，但目前只有生物过程可用于硝酸盐的破坏。在这里，我描述了一个化学过程，其中铝粉将硝酸盐还原为氨，氮和亚硝酸盐。在9至10.5的pH范围内，硝酸盐相对于硫酸盐的选择性还原是可能的，并且在pH 9.1和9.3之间，通过水的分解的还原剂的损失可以最小化至小于2%。随后控制pH值和溶解铝、亚硝酸盐和氨的浓度应该是可能的，成本合理，使这一过程可能有助于防治硝酸盐污染。
HIGHlevels 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 States4and 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.