Princeton University and Michigan schools introduce new ways to filter water (H2O). As global demand for clean H2O rises, the need to improve the performance of treatment processes also needs to be hastened.
Foremost, Princeton reported that the proposed technique using carbon dioxide (CO2) consumes 1,000 times less energy than traditional methods. Princeton postdoctoral researchers Dr. Orest Shardt (University of Limerick) and Dr. Sangwoo Shin (University of Hawaii) led the study. The former hopes that this new discovery could help those in mining, food and beverage production, as well as pharmaceutical manufacturing.
As of now, ways to filter water include microfiltration or ultrafiltration. Per Phys.org, it uses porous membranes to remove suspended particles and solutes. However, energy must be wasted to overcome the friction of pushing the H2O through small passages. Therefore, it is highly expensive and has the need to be replaced periodically due to fouling.
In the study, the experts inject CO2 gas into a stream of water in different channels to screen out particles. The gas temporarily changes the water's chemistry by slightly making it more acidic, per the same source. Now, the changes cause the contaminating particles to move to one side of the channel depending on their electrical charge. Thus, the researchers are able to "split the water" stream and filter out suspended particles.
Shin noted that the new filtration technique may help clean ponds and rivers that have bacteria and dirt. To better illustrate, acidity in CO2 means the production of ions. A positively charged hydrogen atom moves very quickly through the water solution while the negatively charged ion moves very slowly. These movements then create a "subtle" electric field that draws the particles in the water, which have their own negative or positive charges.
To maintain the electric field, the experts needed to keep the ions moving through channels. They have used silicon rubber, a material that is permeable to CO2. Simply, put, pressurized carbon dioxide diffuses through one wall of the channel and pervades the other side. Because the system does not have a membrane or a mechanical filter, clogging is not a problem.
On the other hand, another group of researchers from Michigan universities and hospitals urges people to make the most out of the water filters on their taps. Apparently, they want the consumers to "go beyond the manufacturer's instructions". For one thing, they want users to flush the pipes and filters for longer periods of time every morning or after long periods of not using the tap.
The Michigan study is co-led by the University of Michigan and Wayne State University. Teachers from the Michigan State University, Kettering University, and Henry Ford Hospital System also helped. Indeed, these new ways to filter water will improve the lives of those living in both developed and developing countries with problems in potable water.
