Professor Yuichi Kamiya

Affiliation: Graduate Faculty of Environmental Earth Science /Graduate Graduate School of Environmental Science

Specialized field: catalytic chemistry, environmental purification

Research keywords: solid catalyst, environmental purification material, wastewater treatment, polluted groundwater, nitrogen cycle

Alma mater: Kariya North High School (Aichi Prefecture)

Final academic background: Graduate School of Engineering, Nagoya University

Website address:

*This article was originally published in the 4th issue of "Frontiers of Knowledge" and has been re-edited for the web.

what are you researching?

Our daily lives and the production of goods have a considerable impact on the global environment. In other words, human activity pollutes the earth's environment. Nature has the power to restore itself, but our human activities, which are based on the massive consumption of energy, have such a great impact on the environment that nature's resilience cannot recover. Therefore, in order for our society to continue to develop sustainably in the future, we need not only science and technology to manufacture things (here we call them arterial technology), but also to restore the polluted environment. At the same time, we must also develop the science and technology (venous technology) that is capable of producing products without polluting the environment. Originally, I was researching solid catalysts as arterial technology for the industrial production of chemical products, but now I am particularly interested in solid catalysts for purifying water polluted by human activities. Masu.

Contamination of Groundwater by Nitrate Ions and Catalytic Purification

Currently, the total population of the earth is steadily increasing, partly due to the efficient production of agricultural products. Fertilizer is essential to get as many crops as possible from limited farmland. The Haber-Bosch process, which synthesizes ammonia from air (nitrogen), was developed, making it possible to produce large amounts of nitrogen fertilizer at low cost. However, excessive nitrogen fertilizers spread on farmland have caused groundwater to be contaminated with nitrogen compounds (nitrate ions).It has been pointed out that drinking water containing a high concentration of nitrate ions can cause health problems such as cyanosis (methemoglobinemia), diabetes and hypertension. Therefore, the World Health Organization (WHO) warns against drinking water containing more than 50 mg/L of nitrate. In Japan, the Ministry of the Environment surveys groundwater (well water) nationwide every year, and unfortunately, nitrate ions above the standard value have been detected in about 5% of the surveyed wells.Contamination of groundwater by nitrate ions has a lot to do with food production and the livelihoods of farmers, so it is very difficult to cut off sources of pollution, such as not using nitrogen fertilizers. Therefore, it becomes necessary to purify the polluted groundwater. Several methods have been proposed to remove nitrate from groundwater, but I am researching the chemical decomposition of nitrate in water to gaseous nitrogen. Gaseous hydrogen is blown into contaminated groundwater to chemically reduce nitrate ions, but simply blowing in gaseous hydrogen does not promote this reaction at all. In order to actually proceed with the reaction, a material catalyst that promotes the chemical reaction is required. I am researching the development of high-performance solid catalysts that purify polluted groundwater and how catalysts promote reactions. In addition to decomposing nitrate ions as fast as possible, the catalyst is required to have the performance of suppressing the by-product ammonia as much as possible (because water with an ammonia smell is not drinkable). In addition to nitrate ions, actual polluted groundwater contains various ionic substances and water-soluble organic substances, so catalysts are required to have performance that is not affected by them. Furthermore, cost (price) and toxicity of the catalyst are also issues for practical application of this method, so we must develop a catalyst that satisfies all of these performance and constraints. I am still halfway through, but I am conducting research with a strong belief that it will definitely be possible.

I often hear about environmental problems, but it feels like a distant topic.

That's not true. Japan has abundant rainfall and a high water supply penetration rate, so even if the well water is contaminated, it is unlikely that you will have trouble living right away. However, there are some cities in Japan that rely on groundwater for all of their tap water sources, and it is feared that the situation will become dire in a few decades. Also, since Japan depends on imports for most of its food, it indirectly imports water from countries that produce the food (called virtual water). Japan is connected to these countries through water, and problems such as water shortages and pollution overseas are not unrelated to us. We believe that we must contribute to the preservation of the water environment in these countries by developing and providing various technologies and methods other than purification methods using catalysts, including the technology for purifying nitrate ion-contaminated water. .

What kind of place is a graduate school?

Graduate School of Environmental Science, to which I belong, is a graduate school-only organization with no faculties. In graduate school, there is passive learning through lectures, but students are mainly engaged in research. In addition to acquiring specialized knowledge through lectures, students also train their application and practical skills, such as their ability to think, generate ideas, analyze, plan, and communicate (presentation) through research. Let's all go on to graduate school and explore the vast world of science together.