“I’m not saying I am abandoning nano-technology, but when Nature provides a low cost, efficient, environmentally superior solution, why not go with the natural material.” -- Yi Zheng, Professor Northeastern University, Boston; Director of Nano Technology Laboratory; NASA Research Scientist-- in a conversation with WATERTODAY.
The latest research (led by Dr. Yi Zheng) coming out of the Nano Energy Laboratory in Boston’s Northeastern University is purifying salt and brackish water – free of contaminants, bacteria and viruses. The result -- water that exceeds drinking water standards set by the U.S. Environmental Protection Agency. The simplicity of the revolutionary process is time and cost efficient, sustainable, recyclable, and environmentally supportive. All this is possible with biomass- derived composites and sunlight.
According to recent UNICEF statistics, 1.42 billion people on Earth live in areas of high or extremely high water-vulnerability. That’s one-quarter of the Earth’s population. In the face of exponentially growing population and recurring droughts in many regions of the world – including Canada and the United States -- desalination has been acknowledged as a technology that can help alleviate the identified stress on water resources while also protecting natural habitats and environmental flows.
However, desalination is an energy-demanding process commonly powered by nonconventional energy sources which are unsustainable. Traditionally, desalination processes, are mainly based on thermal and membrane technologies including reverse osmosis for example.
Recently, advances in nanoscale science and engineering have been gaining attention as a means of water purification. “Water desalination is not a new topic,” Zheng tells us. “But all processes are complex, consume electricity, are labor intensive and are also very expensive.
“As far as nano technologies – these materials do not exist in Nature. Materials used in these processes have to be fabricated. Many researchers have accomplished this. But the expensive equipment and time involved are not sustainable. “For example, the use of a freeze drier over several days creates only a small amount of nano-materials.” “My goal is to avoid nanotechnology by taking advantage of clean solar energy and natural biomass – it’s all free.”
The Aha! Moment
Like many breakthrough discoveries, there is a certain amount of chance and timing involved. “It was over a year ago,” Zheng says. “We were all sent home because of the pandemic. I couldn’t go to my lab.” With the extra time on his hands, Zheng took a trip to a local dairy farm to purchase some products. “While I was waiting for the farmer to gather my products, I happened to notice that not only were there a lot of horses and cows on the farm but there was a lot of manure. I mean it was everywhere! “And I got to thinking...cows are vegetarians...the manure is a result of pure digestion...why not harvest the carbon and fabricate my own nano materials...” The farmer was more than happy to provide Zheng with a free bucket of manure which otherwise would be an expensive undertaking to remove from his land.
