Air filter" makes filtration water cost lower

　　The water purification methods we usually use rely on mechanical filters or filter membranes to remove contaminants, but over time, these filtration devices have to be replaced frequently due to blockages. The new water filtration technology developed by researchers at Princeton University does not require any filters, but instead relies on the injection of carbon dioxide gas to change the chemical properties of the water, separating the waste particles according to the charge. The system is simple and low in cost, and is composed of a silicone rubber tube, and one end is divided into two channels. Since the silicone rubber is permeable to CO2, pressurized gas can diffuse through one wall of the tube and mix with the internal water. This interaction changes the chemistry of the water, making it slightly acidic and producing charged particles or ions.

 

　　One of these ions is a positively charged hydrogen atom that moves rapidly through the aqueous solution, while the other is a negatively charged bicarbonate molecule that moves more slowly through the water. The movement of these molecules produces a small electric field, and since most of the particles suspended in water have a charge, they are attracted to one side of the water stream, while the filtered water without charge continues to advance in its own channel. The tube is thus divided into two parts, the filtered water flows through one, and the waste particles flow through the other.

 

　　The researchers pointed out that the system has no more complex moving parts than the bottled carbon dioxide, and if needed, the filtered carbon dioxide can be recycled and reused. Because the filtration system is relatively simple and the cost is mainly pipeline and carbon dioxide costs, the researchers feel that the system has great potential in developing countries. It can be used to clean ponds and rivers contaminated with bacteria and dirt particles. It can be used for desalting plants to remove viruses and bacteria from plants. In addition to water purification, the researchers also said that the technology also has the potential to control the particles in the solution in scientific and industrial applications.

 

　　This water purification technology can be used both for portable water purification systems and for enlarging water purification. Researchers have now established a laboratory-scale system and will develop a large-scale carbon dioxide filter that will make the technology a water treatment plant integrated into large communities. Related reports on the technology have been published in the recent issue of Nature Communications.