New water purification approach is based on insertion of CO2 gas into a water stream rather than filters or membranes to separate particles from water
Conventional water purification methods are based on mechanical filters or a membrane, which eliminate contaminants from water. However, these type of systems face challenges such as they get clogged after certain period of time and need to be replaced. Researchers from Princeton University developed a new technology based on injection of CO2 gas to change the water’s chemistry and separate waste particles based on their electrical charge. The study was published in journal Nature Communications in May 2018.
The system comprises silicone rubber tube, which can be separated into two channels at one end. Pasteurized gas diffuses through one wall of tube and combines with water inside. This chemical interaction alters properties of water resulting into generation of ions. Furthermore, positively charged hydrogen ions move through water solution and bicarbonate molecule with a negative charge moves through the water more slowly. Micro electric field is created by movement of these molecules. Charged particles in water are attracted to one side of wall while purified water, which has no charge continues its channel. The tube then splits in two, with the filtered water flowing through one and the waste particles flowing through the other.
The novel system has potential applications in cleaning up of pond or river water contaminated with bacteria or dirt particles, owing to various advantages provided by it such as simple design, low cost, and lack of bulky filters. Furthermore, it has applications in desalinization plants to remove viruses and bacteria that pass through the membranes and commercial industries to control particles in solutions. The technique could be used in a portable water purification system or it could be scaled up. The researchers have already built a laboratory-scale system that they claim was three orders of magnitude more efficient than conventional microfiltration systems at removing particles from water. Furthermore, the team is working on large-scale carbon dioxide filter that would allow the technology to be integrated in water treatment plants for larger communities.