Scientists get green light for a cleaner world
Stumbling out of bed in the morning, your thoughts turn to a wakeup cup of tea or coffee. You know what you want to drink, but what about the cup. What’s the green choice: paper, china or polystyrene?
Many might say the china cup. But what if we count in the energy spent to make it and the water used to wash it?
You would have to use a china cup at least 1,000 times before it would be environmentally better than polystyrene.
A new option might help environmentalists sleep better at night, according to a leading scientist. Not just sweet dreams, but green dreams.
“We need green chemistry, which reduces or eliminates the use and generation of hazardous substances and makes chemical industry more sustainable,” said Han Buxing, who chaired the International Union of Pure and Applied Chemistry’s subcommittee on green chemistry for five years.
Green chemistry is becoming increasingly popular in China.
In February, a green energy engineering research center got, pardon the pun, the green light in Qingdao, Shandong province.
Within five years it hopes to become a bridge between biomass energy research and industry.
Also in February, Yueyang, a major petrochemical hub in Hunan province, opened a green chemistry park. And other green parks are appearing across the nation.
One sector that is turning green is the printing industry.
An ambitious plan was unveiled to make 30 percent of the printing sector use green technology by the end of the 12th Five-Year Plan (2011-15).
Printing has long used a process called plate-making, which relies on toxic photo-sensitive materials and aluminum. This process can be replaced by a nano-coating technology that greatly reduces the chemical process in printing.
“This is a revolutionary method that could make our printing industry in China the most environmentally friendly in the world,” said Song Yanlin, who developed the technology, which has seen 51 patents taken out in China and 14 patents applied for under the Patent Cooperation Treaty.
Green chemistry is not only about cutting down on the use of toxic materials, but also designing chemicals and products to degrade after use. Developing biodegradable plastic films for agriculture is one example.
In China, a huge amount of polyethylene mulch film is used for better growth and crop yield. The plastic, often seen on farms, is laid in strips and retains water while offering protection from the elements.
In June, Xinhua News Agency reported that a survey in 20 counties in the Xinjiang Uygur autonomous region showed an average of 253 kg of torn plastic film remained on each hectare of land.
“After harvest, these thin polyethylene films can easily break down to small fragments, and they are hard to collect and recycle,” said Zhang Jun, a scientist who specializes in natural polymers.
To solve this problem, Zhang and his team are developing technology to make plastic film from plant cellulose, which is renewable and biodegradable.
“Most industrial plastics are made from petrochemicals and consume a huge amount of petroleum resources. Moreover, almost all of these plastics are non-biodegradable.
“In contrast, plant cellulose is abundant, renewable and it exists in all plants. More important, it degrades to carbon dioxide and water and returns to nature after being used,” he said.
Recently, plant cellulose film has been successfully prepared through a simple and “green” method in Zhang’s laboratory. A Chinese company is investing about 10 million yuan in developing the technology for industrial production, Zhang said.
Green chemistry targets the use of hazardous substances and points the way to the future, said Fan Qinghua, an organic chemistry specialist.
“Chemists hope to invent ‘ perfect chemical reactions’. The desired product is obtained without forming any waste. This is the ultimate goal of green chemistry,” he said.
Green chemistry is not just an academic matter, experts said, and it must be targeted well.
“Only if research combines with need will the new methods produce benefits for the environment,” said Zhang Deqing, director of the Institute of Chemistry at the Chinese Academy of Sciences.
To encourage green chemistry research, the CAS has launched a dozen projects that allow researchers to iron out technological problems, and these projects are also open to companies.