Link: http://www.reuters.c...03&pageNumber=0
Date: 10-30-03
Author: Risa Maeda
Source: Reuters
Title: Germ-Wary Japanese Fuel New 'Green' Technology
Germ-Wary Japanese Fuel New 'Green' Technology
Thu October 30, 2003 08:40 PM ET
By Risa Maeda
TOKYO (Reuters) - Car dealer Takeshi Kiyomiya has a piece of wall at his shop in central Tokyo that stays remarkably clean despite the bombardment of dirt and grime from one of the city's main thoroughfares.
"When spraying the wall, the water running off is usually dark with dust and dirt. But it's really amazing to see how clean the water from that part is," said Kiyomiya, pointing to the wall.
The section's ceramic tiles are coated with a thin film of soot-eating nanoparticles made by top toilet maker Toto Ltd (5332.T: Quote, Profile, Research) from titanium dioxide, a pigment commonly used in cosmetics and white chocolate.
The substance acts as a photocatalyst, using light and oxygen to break down organic compounds and producing carbon dioxide and water -- the reverse of photosynthesis in which plants use light to produce organic matter and oxygen from carbon dioxide and water.
The technology holds such promise for removing nitrous oxide and other petrochemical by-products of fossil fuels from the air and water that supporters have called it a "green technology" as important as the solar cell.
"What we're working on now is a way to swiftly convert the by-products of fossil fuels, which are derived from organic compounds produced by plants, back to carbon dioxide and water," said University of Tokyo Professor Kazuhito Hashimoto, one of the main researchers behind the technology.
Hashimoto first got the idea of coating flat surfaces with titanium dioxide, which he had started studying nine years earlier, after noticing a dirty university toilet one day in 1989, the peak of Japan's asset bubble era.
It occurred to him that he could fight the grime by exploiting the Honda-Fujishima effect, a phenomenon discovered in 1972 by the two Japanese researchers in which a semiconductor -- such as titanium dioxide -- electrolyses water, breaking it down into hydrogen and oxygen, when exposed to sunlight.
In hygiene-conscious Japan, the technology is increasingly being used for a wide variety of applications.
Tiles, glass, tent sheets, tunnel lights, highway barriers, air purifiers and other goods featuring the technology accounted for some $277 million in sales in Japan in 2002.
In addition to its growing popularity with Japanese consumers, whose wariness of germs fuels a heavy demand for products such as face masks, wet tissues and odor-free socks, it also appeals to Japan's hospitals, auto makers, road builders and real estate developers.
The surface of the photocatalyst attracts water, which then acts like detergent, preventing the formation of tiny droplets and making the substance useful for such products as fog-resistant mirrors and anti-stain materials for exterior use.
Asahi Glass Co (5201.T: Quote, Profile, Research) and Matsushita Electric Works Ltd (6991.T: Quote, Profile, Research) jointly have used Toto's patented process to develop windows that only have to be cleaned once a year, rather than the standard six times.
Toto earned 250 million yen in patent fees from the technology in the last business year ended in March, and expects fee income to increase to one billion yen in 2005/06.
Daikin Industries (6367.T: Quote, Profile, Research) , which uses a similar filter-based technology, expects to this year sell 20,000 of its 39,800 yen ($367) photocatalyst air cleaners to households in Japan after selling just 200 a year ago.
The cost is about two to four times as much as ordinary cleaners but the company says they can more effectively eliminate viruses, such as SARS, not to mention smoke and other odors.
The company plans to market the latest version of the cleaners in the rest of Asia, where it believes demand will be high because of this year's SARS outbreaks.
ENVIRONMENTAL CHALLENGES
Despite its environmentally friendly properties, the technology has yet to catch on globally.
One issue is the lack of international standards to gauge the effectiveness of such products. The International Organization for Standardization (ISO) only took up the issue this month, at the behest of Japan.
Manufacturers are wary of losing consumer trust should the market become flooded with unreliable or fake photocatalyst products that don't work.
"I think Japan is responsible for establishing evaluation procedures, since we have built up the know-how in our years of research," said Mitsugu Yamashita, chief researcher at Daikin Industries.
In the United States, Europe and the rest of Asia, companies have brought photocatalyst products onto the market only in the past few years. There were almost none, even in Japan, in 1998.
"We see several hurdles ahead, including difficulties in applying the technology to more lucrative and essential areas, such as waste water treatment," said Shinichi Kamei, senior staff researcher at Mitsubishi Research Institute.
These are the areas, the so-called three-dimensional environments, in which mainly European and U.S. researchers have been struggling to apply the technology.
Advances in these areas, though, aren't likely to come soon.
Japan's experience in the past three decades suggests that photocatalysts work well on flat surfaces, like car dealer Kiyomiya's wall, but they aren't as effective in larger-scale applications, such as cleaning up massive air or water pollution
