Denitrification of underground water by chemical adsorption and by electrodialysis

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• 作者：Annouar ; S. ; Mountadar ; M. ; Soufiane ; A. ; Elmidaoui ; A. ; Sahli ; M.A. Menkouchi ; Kahlaoui ; M.
• 关键词：Denitrification ; Underground water ; Adsorption ; Electodialysis
• 刊名：Desalination
• 出版年：2004
• 出版时间：August 15, 2004
• 年：2004
• 卷：168
• 期：Complete
• 页码：185
• 全文大小：94.1 K

文摘

Today more than ever, the protection of health and the respect for the laws of nature are among man's main preoccupations. One of the main concerns, comes is that of nitrates. However, since about fifteen years in a number of Moroccan regions, as well as in many foreign countries, one sees a continuous increase of nitrate concentrations in underground and surface waters to be used as drinking water. The principal health risks to consider at the time of the consumption of nitrates in large quantities are methemoglobinemy and the formation of nitrosamines that are carcinogenic and that reach the stomach or the liver. The denitrifcation of waters becomes obligatory. Various methods have been tested for the denitrification of waters which are biological denitrification, ion exchange and membrane techniques. Chitin and chitosan are two biopolymers products by certain animals. They are therefore biodegradable and bioresorbable, two primordial properties to our time where the protection of the environment plays an important role. The chitosan caused a quicker interest than the chitin, since it has a greater number of important amino groups on its chain. The first applications have been developed in domains where the chitosan presented a notorious interest notably in pharmacology, cosmetology and especially in medicine. It is only later, with the hold of country conscience, that it was necessary to master the polluting dismissals that the first studies concerning properties of the chitosan to fix the heavy metals were undertaken. Electrodialysis is one of membrane processes that proved their reliability and efficiency. The main application of the electrodialysis is its utilization for the brackish water desalination, the electrodialysis is also used how process of demineralization and deacidification in the food processing industry. Other applications are in progress of development are metallurgy, chemistry, pharmacology, biotechnology and treatment of water and effluents. The interest in this work is threefold. Firstly, with the help of a natural chitosan, we achieve denitrification by chemical adsorption. Secondly, using a laboratory electrodialysis cell and a pre-industrial pilot plant, we achieve a denitrification of underground water a stemmed the region irrigated loaded in nitrate. Thirdly, we make a comparative survey between the two processes.