Chemicals

July 12, 2007

 

Innovative Technology Treats Fluoride-Contaminated Soil

Keywords: Chemicals University / Research institute 

Associate Prof. Masamoto Tafu, Professor Tetuji Chohji and their research group in the Department of Ecomaterials Engineering, Toyama National College of Technology in Japan has developed a new soil treatment method that makes it possible to prevent the spread of fluoride contamination into surrounding soil for several hundred years. The research was presented at the Scientific Instruments Show (SIS) Japan 2006 at Tokyo Big Sight (Tokyo International Exhibition Center) on December 1, 2006.

The research was supported by a subsidy program of the New Energy and Industrial Technology Development Organization (NEDO) for industrial technology research. With the technology, a simple and easy treatment of contaminated soil takes only one day of curing, in order to reduce the amount of fluorine elution to levels at or below the government-regulated concentration of 0.8 mg per liter. The method also has lower soil treatment costs compared to other methods.

The research team found that calcium hydrogen phosphate dihydrate (DCPD) molecules form nanoscale surface structures, inducing a certain reaction with fluorine compounds. Exploiting this reaction, the technology enables fluorine compounds in soil to turn into stable fluoride compounds such as fluorapatite. A patent was pending as of February 2006. The team and its business partners plan to jointly develop the technology for mass production of calcium phosphate and conduct further field tests for soil treatment.

Excessive intake of fluorine, which exists widely in the natural world, causes nerve damage and other serious impacts on human organisms. The Soil Contamination Countermeasures Law, which entered into force in February 2003, established greater restrictions on concentrations of toxic substances in soil when contaminated land is to be reused. Existing soil treatment methods mainly target organic chemicals and heavy metals, but sufficient measures have not been taken against natural compounds such as fluoride. Thus, there have been many cases of public concern in Japan where the regulated standards on fluorine have been violated in vacant lots to be converted from factory site to residential uses or athletic ground.


http://www.toyama-nct.ac.jp/

Posted: 2007/07/12 04:05:52 PM
Japanese version

 

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