Overcoming the difficulties of nanotechnology water treatments means developing innovative solutions to engineer a usable product. One answer could be to develop methods where the nanoparticles need not be suspended in the water. For example, one can stick — or ‘immobilise’ — the nanoparticles onto suitable materials such as steel or polymer sheets,which in turn can be easily dipped in and out ofwater tanks to work as catalysts or adsorbents.
This needs care to retain nanoparticles’ size and integrity so as to keep the benefits of operating at the nanoscale. But if it can be done, immobilisation is a good technique since it would keep water free of nanoparticles during and after water treatment. We, here at the Indian Institute of Science, Bangalore, are developing such a technique for degrading organic molecules using nano titanium dioxide. The results have been very promising and we are working closely with the University of Johannesburg to scale up the process in the near future.