(182e) Functional Nanoparticles and Nanocomposites for Treatment of Contaminants in Water: From Materials to Devices

Taking recourse to nanoparticles and their composites for making more functionally efficient materials for sustainable solutions is a modern theme across several disciplines. We have applied this for removal of certain contaminants (e. g. microorganisms like E. coli, metals and antibiotics), which is a core requirement for having access to clean water.

With regard to microbial contamination, it is imperative to have a low-cost and continuous supply of potable water, devoid of any microbial population. To this end, we have developed silver and copper nanoparticle-impregnated activated carbon (see figure) as a cheap, sustainable material which have been demonstrated to produce clean water, on treating E. coli containing input water. We have done systematic experiments and analysis of batch, shake-flask experiments initially, and then with continuous filter-columns, to discern the mechanism of complete killing of bacteria and the resultant kinetics of water disinfection. Substantially enhanced disinfection rate was possible due to synergy between silver and copper nanoparticles.

Subsequently, this has been translated to the design of two successive generations of gravity-driven water disinfection devices achieving the target of continuous production of potable water, which runs without the use of any electricity or other power sources (see figure). For example, on taking E. coli of 10⁴ CFU/ml as continuous source of contaminated water, we have used our device to produce disinfected water continuously up to several weeks over many hundreds of liters, suitable for a household.

Presently, ongoing experiments in our designed microfluidic device mimics the intergranular-carbon pores, simulating the nanoparticle-carbon-bacteria three-way contact, to gain fundamental insights into this biotic-abiotic interaction, driving the enhanced water disinfection rate.

Along similar lines, we investigate other nanoparticle composites developed by us, for removal of contaminants, like metals, antibiotics etc., which are critical in either drinking water or wastewater treatment applications.