14 DAY TRIAL // Researchers at the D.J. Sanghvi College of Engineering, in Mumbai, India, wrote in the International Journal of Nuclear Desalination that several nanotechnology water purification techniques are currently being tested, are some are used already. “Water treatment devices that incorporate nanoscale materials are already available, and human development needs for clean water are pressing," explain team members Alpana Mahapatra, Farida Valli and Karishma Tijoriwala.
Nanotechnology refers to a wide range of techniques, tools and applications that involve particles the size of a few nanometers in diameter. Such small particles have unique physicochemical and surface properties which allow them to be used in many domains. Nanotechnology fans say that this could be the solution to many major global problems related to medicine, energy, agriculture and even drinking water.
For purifying water through nanotechnology, nanoscopic materials like alumina fibers for nanofiltration and carbon nanotubes are necessary. This technique also uses nanoscopic pores in zeolite filtration membranes, nanocatalysts and magnetic nanoparticles. For detecting contaminants in water samples, nanosensors based on titanium oxide nanowires or palladium nanoparticles are used.
Researchers clarify that the degree of detecting impurities depends on the stage of the water purification process and the techniques are applied depending on it. Nanotechnology can be used to remove sediments, charged particles, chemical effluents, bacteria and other pathogens and it can also remove toxins like arsenic or impurities like oil.
They say that “The main advantages of using nanofilters, as opposed to conventional systems, are that less pressure is required to pass water across the filter, they are more efficient, and they have incredibly large surface areas and can be more easily cleaned by back-flushing compared with conventional methods.”
Scientists add that carbon nanotubes, for example, can remove nearly all contaminants, including oil, bacteria, turbidity, organic contaminants or viruses. Even if they have smaller pores, they are as effective as conventional filters with larger ones, possibly because of the smooth interior of the nanotubes. Filters made out of nanofibrous alumina or other nanofiber materials also remove bacteria, viruses as well as organic and inorganic colloids, much faster than conventional filters would do.
"While the current generation of nanofilters may be relatively simple, it is believed that future generations of nanotechnology-based water treatment devices will capitalize on the properties of new nanoscale materials," the team adds.
Even if nanomaterials can be more reactive than their bulk versions, so far there has been no human health or environmental problem. Still further research on interactions between nanoparticles is advised.