AsianScientist (Jun. 27, 2019) – Scientists at the University of Hong Kong (HKU) have invented an efficient and highly permeable nanofibrous membrane that can effectively filter various contaminants in water, particularly heavy metals and bacteria. The invention won a gold medal at the 47th International Exhibition of Inventions in Geneva, Switzerland.
Many poorer regions of the world and disaster-hit countries grapple with the lack of clean drinking water. Heavy metals such as lead in water can cause poisoning, while waterborne bacteria can cause gastrointestinal infections that could prove life threatening.
Seeking to raise access to clean drinking water, researchers led by Professor Tang Chuyang at HKU developed a nanofibrous membrane that can rapidly filter heavy metals such as lead, nickel, cadmium and chromium with greater than 99.9 percent efficiency. At the same time, the membrane eliminates bacteria such as Escherichia coli and Bacillus subtilis in water.
Importantly, the membrane filter is operated via a gravity-driven filtration process, which means that it does not require any electricity or energy input in its operation. This is unlike other conventional water treatment methods for removing heavy metals, such as reverse osmosis and distillation, which consume energy.
The invention can also be reused many times because any contaminants it traps can be removed simply by rinsing with vinegar. In addition, the price of the membrane filter is expected to be 30-50 percent lower than similar products using carbon filters on the market.
Tang’s team has already received a US and a Chinese patent for their product, with another US patent underway. The researchers note that their technology can even be adapted for use in household water filters and portable water filtration bottles.
“This nanofibrous membrane was designed with an initial motivation to address the critical need for clean and drinkable water in the aftermath of major natural disasters. After an earthquake or tsunami, there is often a lack of reliable source of clean water or electricity, so you need something practical for disaster relief,” Tang explained.
“Our filter fits in very well: it delivers safe drinkable water in less than one minute. [It is] simple and reliable, and no electricity is needed. It is [also] compact and can easily fit into a pocket. The filter has received great interest and attention from travelers and adventurers,” he added.
Going forward, Tang and his team are researching on expanding the nanofibrous membrane’s function to filter a wider range of contaminants and to achieve rapid water purification.
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Source: University of Hong Kong.
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