Nanoparticle-based remediation of chromium-contaminated water exhibits excessive effectivity – Uplaza

Groundwater is a necessary supply of ingesting water throughout the nation. Nonetheless, heavy steel contamination in groundwater presents a big well being hazard. Researchers on the Indian Institute of Science (IISc) have developed a nanomaterial-based resolution that may successfully scale back the presence of heavy metals like chromium in groundwater.

The crew contains researchers from the Heart for Sustainable Applied sciences (CST), Division of Civil Engineering (CiE), and Division of Instrumentation and Utilized Physics (IAP). The examine is printed within the Journal of Water Course of Engineering.

Chromium usually enters soil and groundwater by way of effluents from industries resembling leather-based tanning, electroplating, and textile manufacturing. “Heavy metals enter the environment because of urbanization and certain mismanagement by industries,” says Prathima Basavaraju, Ph.D. scholar at CST and lead writer of the examine.

Most present strategies for eradicating heavy steel contamination depend on pumping out water from the bottom, adopted by purification utilizing chemical precipitation, adsorption, ion trade and reverse osmosis carried out at a unique location. The IISc crew as a substitute proposes an on-site various which includes utilizing iron nanoparticles that may remediate the heavy metals.

“If the groundwater is contaminated, we can inject these nanoparticles into the subsurface groundwater region where it will react with the chromium and immobilize it, resulting in clear water,” Prathima explains.

The group first tried synthesizing nanoparticles consisting of nano zero-valent iron (nZVI). This type of iron can react with the poisonous and carcinogenic type of chromium (Cr⁶⁺) and scale back it to a much less dangerous type (Cr³⁺), which in flip ends in co-precipitation. Nonetheless, the crew quickly realized that the nZVI particles are likely to clump collectively, limiting their utility.

To stop clumping, the crew turned to carboxymethyl cellulose (CMC). “We modified nZVI by coating it with CMC. It forms a stabilizing layer around nZVI separating individual particles,” Prathima explains. The CMC coating moreover extended the lifetime of the fabric by stopping oxidation of the iron core.

The crew additionally boosted the reactivity of the CMC-nZVI by exposing it to sulfur-containing compounds in anoxic circumstances. This enabled the formation of a protecting iron sulfide layer on the floor, a course of known as sulfidation. These modifications improved the soundness of the S-CMC-nZVI and maintained its reactivity and effectivity.

S-CMC-nZVI confirmed almost 99% effectivity at Cr⁶⁺ elimination below totally different circumstances resembling totally different pH ranges and the presence of different competing ions that could be present in groundwater. The crew examined this enhanced nanomaterial in circumstances that mimic the pure surroundings of groundwater aquifers.

After they pumped contaminated water by way of sand columns containing the nanomaterial, they noticed strong remediation exercise. Experiments had been additionally performed on contaminated soil and sediments utilizing nZVI to immobilize the heavy metals. Scaling up experiments are nonetheless in progress.

The authors counsel that S-CMC-nZVI is a promising materials for on-site remediation of chromium-contaminated groundwater. “Places like Bellandur lake [in Bengaluru] have a lot of contaminated sediments,” factors out GL Sivakumar Babu, Professor at CiE and CST, and co-author.

“The technique developed can also prove quite useful in remediating contaminants such as cadmium, nickel, and chromium in contaminated sediments of Bellandur lake.”