14 DAY TRIAL // Most water is purified for human consumption (for drinking it) and its purification consists of removing contaminants from a raw water source, like particulate sand, suspended particles of organic material, parasites, bacteria, algae, virus and minerals.
Now, a team of researchers are involved in an ambitious project to purify the world's waters, using a new membrane-based technology, with funding from the National Science Foundation (NSF). Volodymyr Tarabara and Tom Voice are two Michigan State University professors, working together with environmental engineers and scientists from two research centers in France and three institutions in Ukraine and Russia.
"Membrane-based technologies selectively remove things such as chemicals and particles from water," said Voice, professor of civil and environmental engineering. "They are analogous to filters except they remove things that are smaller and separate on the basis of chemistry and size. Our project is looking at developing new types of membranes and membrane systems that perform better in water treatment applications."
The idea is based on the main advantage of using membranes, the fact that it can remove almost everything, to produce ultrapure water. Thin film composite membranes are semipermeable membranes manufactured principally for use in water purification or desalination systems. They also have use in chemical applications such as batteries and fuel cells.
"For example, research to develop stronger hollow fiber membranes will unite the world-renowned expertise in carbon nanotube chemistry at Rice University with the knowledge of hollow fiber membrane manufacture and optimization at France's National Polytechnic Institute of Toulouse," said Tarabara.
"Development of high-flux membranes to remove heavy metal contaminants will include the group in Kiev, which is heavily involved in this work due to local environmental contamination, along with a group from MSU which is developing high-flux membranes that reject large molecules."
Membranes used in reverse osmosis are typically made out of polyimide, chosen primarily for its permeability to water and relative impermeability to various dissolved impurities including salt ions and other small, unfilterable molecules.