Method for the Production of Deuterium-Depleted Potable Water
Feng Huang and Changgong Meng*
Department of Chemistry, Dalian University of Technology, Dalian 116024, China
Ind. Eng. Chem. Res., 2011, 50 (1), pp 378–381
Publication Date (Web): November 29, 2010
Copyright © 2010 American Chemical Society
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A study of the utilization of dual-temperature catalytic exchange between water and hydrogen for the production of deuterium-depleted water is presented. We use a novel catalyst with excellent physical properties for the hot tower of the isotopic exchange. The deuterium-depleted water obtained from the experiment is in agreement with the theoretical consideration on deuterium content at 80 °C when λ is about 1.5. The deuterium-depleted water with 126.3 ppm D2O is gained when λ is about 2 under 80 °C. This kind of water can be used as ordinary drinking water and in cosmetic and hygiene products.
The exceptional properties of heavy water as a neutron moderator make it useful in nuclear reactors. The significance of deuterium in the nuclear industry is also well-known. Various methods have been developed for the separation and purification of deuterium,(1-5) especially for the production of heavy water,(6) such as, chemical exchange, liquid hydrogen distillation, cryogenic adsorption, and thermal diffusion. Nevertheless, accumulating evidence indicates that deuterium in drinking water can be detrimental to health. For instance, there is evidence to show that high concentration of deuterium in water (heavy water) will cause the loss of activity and various diseases in higher animals such as quail,(9) trout,(11) and others,(7)and in addition, some aquatic plants stop growing and developing in heavy water.(8, 9)
Contrarily, decreasing of the deuterium concentration will improve the biological activity of the water. Natural water is a mixture of H2O and D2O in which the concentration of deuterium is approximately 150 ppm. Deuterium-depleted water in which the concentration of deuterium is less than 80 ppm is usually used in medical treatment. Deuterium-depleted water with about 125 ppm deuterium is generally used in ordinary drinking water and in the cosmetic industry.
The function of deuterium-depleted water can be divided approximately into two aspects. First, deuterium-depleted water could promote animal and plant growth and play a significant role in health care. For instance, there is an increase in the rate of photosynthesis of plants and growth promotion effects for agricultural products and aquatic animals with use of low deuterium water as compared to control groups using standard water.(10-13) Second, deuterium-depleted water can be applied to cancer therapy. The daily drinking water of the patients is replaced by deuterium-depleted water, which is administered as an anticancer agent besides conventional therapy, and it remarkably prolonged the survival time of the patients.(14-17)
Therefore, the subject of the production of deuterium-depleted water has attracted much interest of scientists. Deuterium enrichment and depletion are simultaneous processes. Various technologies have been developed for the production of deuterium poor water, such as electrolysis,(18) distillation,(19, 20) desalination from seawater,(7) and Girdler-sulfide (G-S) process.(21) Separation by electrolysis is based on the difference between the mobility coefficients of the ions. This method is very expensive as electrolysis is a high-power consumption process. Separation by distillation is based on the difference between the boiling points of the molecules. This method uses simple equipment and is a simple operation technology, but has high-energy consumption. Desalination from seawater by using solar energy is an energy-saving and environment friendly method, but it is inefficient. The G-S process is a dual-temperature exchange method between hydrogen sulfide and water. This process uses the very hazardous material hydrogen sulfide. Besides these four methods, there are two processes that could be applied for producing deuterium-depleted water. One process is combined electrolysis and catalytic exchange (CECE). An alternative process is bithermal hydrogen water (BHW). In each stage there is an upper cold tower where the deuterium transfers from the hydrogen to the liquid water, and a lower hot tower where the deuterium transfers from the water to the hydrogen gas.
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