Single-step removal of Hexavalent chromium and phenol using meso zerovalent iron.

Author(s) Ambika, S.; Devasena, M.; Nambi, I.M.
Journal Chemosphere
Date Published 2020 Jun

Novel meso-zero valent iron (mZVI) was investigated for treating complex wastewater containing toxic heavy metal Cr and organic compound phenol. This study is first of its kind illustrating coupled removal in single-step with HO playing a major role as an oxidant and reductant. The mechanism involved was electron transfer from Fe to Cr resulting in Fe which in turn was consumed for phenol oxidation returning as Fe into the system for further Cr reduction. While comparing, single-step simultaneous removal of Cr and phenol showed better performance in terms of pollutant removal, Fe recurrent reaction and precipitation generation, double-tep sequential removal performed better in iron active-corrosion time. It was also observed that the entire redox cycle of Cr-Cr-Cr was reusable for co-contaminant phenol degradation at all pH with the recurrence of Fe-Fe-Fe. The proposed technique was checked for its viability in a single batch reactor and the complex chemistry of the reactions are unfolded by conducting chemical speciation and mass balance study at every stage of reaction. The unique functioning of mZVI was proven with micro-analysis of ZVI's surface and compared with granular ZVI, cZVI. The results obtained from this study open the door for a safer and cleaner single treatment system in removing both toxic heavy metals and organic compounds from contaminated surface water, groundwater and many such industrial effluents.

DOI 10.1016/j.chemosphere.2020.125912
Keywords Chromium; Corrosion; Groundwater; Hydrogen Peroxide; Iron; Oxidants; Oxidation-Reduction; Phenol; Phenols; Waste Disposal, Fluid; Waste Water; Water Pollutants, Chemical
ISSN 1879-1298
Citation Chemosphere. 2020;248:125912.