Nanotechnology for drinking water purification
T. Pradeep E-mail: pradeep@iitm.ac.in Website: http://www.chem.iitm.ac.in/professordetails/profpradeep/index.php Intensive farming, rapid industrialization and varying lifestyles have added artificial chemicals into the water bodies. Natural contaminants such as arsenic and fluoride have been major problems in several parts of the world and certain regions in India. While pesticide residues in ground water were unexpected years ago as soil was thought to act as a filter, it is an established fact that even drinking water is contaminated with them in many parts of the world. Although these levels are significant, the concentrations are low in comparison to those of commonly encountered chemicals and the purification technologies have to be efficient for them to be removed at affordable cost. In addition, the kinetics of the processes has to be such that a single encounter event with the removal medium must eliminate them effectively. As the affected populations may be at remote locations, inaccessible to piped water supply, such methodologies have to be used also for point-of-use water purification applications. People in such locations are often poor and for any solution to be adopted by these affected populations, it has to economically competitive. These offer numerous challenges to chemistry and engineering. In the larger context, as we become aware of the greater and greater risks involved in drinking water contamination, the allowed limits are being revised and the contaminants levels are expected to reach molecular limits in the years to come. This implies that the technologies we use have to become molecule-specific and nanotechnology becomes the obvious choice. This is because nanotechnology means engineering at the atomic or molecular level. |
