Bangalore, November 20 : In a shot in the arm for India, researchers at the Indian Institute of Science (IISc) have found that a novel nanomaterial-based solution that can quickly remove toxic heavy metals such as Chromium and Molybdenum from contaminated water — drawn from metal plating (depicting nickel), cement manufacturing industries, heaving-vehicle servicing and dye manufacturing sources.
Handling of Chromium Contamination
Although groundwater is among the primary sources of drinking water nationwide, its pollution by heavy metals is a key problem area and a major public health risk. This, heavy metal is generally introduced in soils and groundwater by industrial effluents from industries eg., leather tanning, electroplating, textile manufacturing etc.
Conventional methods for removing heavy metal contamination generally involve draining the water from the ground, followed by elaborate cleansing procedures such as chemical precipitation, adsorption, ion exchange and reverse osmosis. However, such methods are very time-consuming and resource-intensive and may even necessitate the water to be carried away from-place-to-place for treatment (in contradiction of in-situ approaches). Using Drosophila cells, a team from the IISc led by Prathima Basavaraju in collaboration with Mohan hiredinker of [the] St. The copper oxychloride crystals dissolve when making contact with acidic medium, releasing the encapsulated chemical over a period of time.Charles Vora, an M. Tech. student at CST has come up with yet another effective alternative that could transform the manner in which toxic chromium plagues humanity on its quest for potable water.
The Nanomaterial Solution
The IISc team has successfully designed an unprecedented nanomaterials-based technology that can be used to rectify heavy-metal chromium contamination in the contaminated groundwater. They utilize iron nanoparticles that reacts with carcinogenic and hazardous form of chromium (Cr6+) and convert it to less toxic form (Cr3+) hence making them coprecipitate.
However, the team quickly found that the nZVI particles tended to aggregate with each other, and were not effective. In one approach to address this, a stabilizing agent such as carboxymethyl cellulose (CMC) was employed. Covering the nZVI particles with CMC created a cover to keep them separate, increasing spread.
But the team did not just stop in that. In addition, they increased the reactivity of CMC-coated nanoparticles through exposure to sulfur-containing compounds in a low-oxygen (anoxic) environment. This is a process called sulfidation which created an iron sulfide shell around the particles and this made them more stable, reactive and efficient.
Conclusion
The novel nanomaterial solution of the IISc team can pave a path for cleaning up heavy metals from groundwater in India. The enhanced S-CMC-nZVI nanoparticles developed by the group can be efficiently used to immobilize contaminants such as chromium and other heavy metals in situ simply by injecting them into soil/sediment, therefore bypassing the necessity of translocation of contaminants for remediation in elaborate water treatment facilities. This could be a game changer over conventional on-site remediation to tackle contamination hotspots such as the now infamous Bellandur lake in Bengaluru, and possibly herald a more sustainable and effective method of protecting our dwindling groundwater resources.
