• Self-propelling nanomotors, just 200 nanometre in size, could be used for wastewater management in chemical industries.
  • The nanomotor can be used for transporting catalysts needed in harsh chemical environments and removing unwanted chemicals in water.
  • Nanorods (rod shaped nanomotors) are made using ammonium heptamolybdate tetrahydrate and dispersed in the solution to be treated.
  • When hydrazine sulphate is added to water, it reacts with the nanorods producing nitrogen gas. This leads to an osmotic stress in the fluid and causes the nanorods to move along the direction of the gas evolved.
  • Molybdenum based soft-oxometalates are non-toxic and easy to synthesize.
  • The complementary charge interactions on the surface trigger their motion.
  • The speed can be increased by increasing the concentration of the fuel hydrazine on the surface of the nanorods and they were found to remain in their motile state for about three days.
  • The anterior end of these structures is capped like a pencil while the posterior end consists of a series of rod like protrusions.
  • The fuel hydrazine preferentially reacts at the posterior open end and generates gaseous nitrogen which triggers motion and the propulsion speed reaches up to a maximum of 600 metres per hour.
  • The researchers have shown that another type of nanomotor in the form of a sphere (using titanium dioxide, heptamolybdate and gold) can also be used for delivering a catalyst to a particular area of interest by using visible light.
  • The nanospheres were found to move away from visible light.
  • The catalyst triggers a reaction and the pollutants get adsorbed on the nanospheres leading to quickly removal of organic pollutants from water.
  • The solution can then be filtered, dried and the nanosphere can be retrieved.