About "Purification of polluted groundwater"

 

　Profile #22: Dr. KAMIYA Yuichi, Professor

　Group of Functional Materials Chemistry,

　Section of Environmental Materials Science, Faculty of Environmental Earth Science

 

　【Research Topics】

　・Development of catalysts for purification of polluted groundwater

 

 

 

 

～Purification of groundwater polluted with nitrate nitrogen～ 

 

The 21st century is said to be the century of water, and securing clean water is the basis for building a sustainable society. Since groundwater is an excellent water resource with good water quality and little fluctuation in water volume throughout the year, sustainable use of groundwater is indispensable to secure clean water in the future. However, groundwater pollution caused by the qualitative and quantitative increase in human activities has become more serious in recent years around the world. Contamination of groundwater with nitrate nitrogen is one of them. Large-scale and centralized agriculture has dramatically improved the production of agricultural products. However, the excess nitrogen fertilizer on the fields turned into nitrate nitrogen in the soil, resulting in pollution of groundwater through the infiltration of rainwater. In this pollution, it is difficult to take measures to remove the pollution source because the pollution source is widespread. Thus, it is a realistic solution to purify and use the polluted groundwater.

We are conducting research on the development of catalysts for reacting nitrate nitrogen in groundwater with hydrogen to decompose it into gaseous nitrogen, which is the main component of air. When nitrate nitrogen reacts with hydrogen, it also produces ammonia, which gives off a foul odor, so how to suppress it is the key to catalyst development. Since most actual facilities purifying groundwater are small household-level ones, using hydrogen is difficult to handle.  Thus, we are also studying on methods for purification of contaminated groundwater without using hydrogen, which include sunlight-driven photocatalytic reaction system and ion-exchange method with ion-exchangers. 

 

　　　　　　　　　　　　　　

An illustration of a purification process for decomposition of　　　　　A transmission electron microscopy image of a catalyst active

nitrate nitrogen by the rection with hydrogen into nitrogen.　　　　　 for the decomposition reaction.

 

Field work around farmland with polluted groundwater.