The use of zerovalent iron nanoparticles (nZVI) immobilized in a chitosan (CS) polymer matrix is presented as an innovative and efficient solution for the removal of Cr(VI) in wastewater. nZVI, recognized for their high redox reactivity, have proven to be highly effective in removing various contaminants, including heavy metals. However, their tendency to agglomerate in aqueous media significantly reduces their surface area, reactivity, and mobility. To overcome these limitations, the formation of millimeter nanocomposites (NCs) by immobilizing nZVI is proposed, which facilitates their application in continuous flow systems as filling columns or reactive barriers.
The Liquid Effluent Laboratory of the National Institute of Industrial Technology (INTI) in Argentina produces 30 liters of liquid waste contaminated with Cr(VI) annually, the possibility of treating this wastewater internally becomes crucial.
The objective of this work was to develop an accessible and efficient treatment method that allows the reuse of wastewater generated in water quality analysis. To this end, the synthesis of NCs was optimized by exploring routes such as the prestabilization of nZVI with carboxymethylcellulose (CMC) and the use of CS with different molecular weights, obtaining materials with greater mechanical stability and reactivity. The characterization of the materials confirms their structure and stability, finally demonstrating that the NCs produced remove Cr(VI) from water to comply with water quality regulations and offer a cost-effective solution for the treatment of liquid waste contaminated with Cr(VI).
This research is closely aligned with the principles of green chemistry, in particular with the design of safer syntheses through the use of nanomaterials with reduced ecotoxicity, such as nZVI, the reuse of industrial waste products like CS and the pursuit of energy-efficient processes for water treatment.