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The Chemistry of Hazardous Materials
Published in Armen S. Casparian, Gergely Sirokman, Ann O. Omollo, Rapid Review of Chemistry for the Life Sciences and Engineering, 2021
Armen S. Casparian, Gergely Sirokman, Ann O. Omollo
Two compounds of particular interest containing oxo-anions are potassium chromate, K2CrO4, and potassium dichromate, K2Cr2O7. Chromium is present in the hexavalent oxidation state, Cr6+, in both the chromate anion, CrO42−, and the dichromate anion, Cr2O72−. Potassium chromate can be produced first by treating chromite ore, represented as FeCr2O4(s), with potassium carbonate and atmospheric oxygen, i.e., air in a kiln. Potassium dichromate can be subsequently produced by treating potassium chromate with sulfuric acid as follows: 2K2CrO4(s)+H2SO4(aq)→K2Cr2O7(aq)+H2O(l)+K2SO4(aq)
Effectiveness of common macrophytes for phytoremediation of hexavalent Cr prevalent in chromite mining areas
Published in International Journal of Phytoremediation, 2021
Madhumita Das, P. S. Bramhanand, K. Laxminarayana, S. Roy Chowdhury
The commonly grown aquatic macrophytes viz. Pistia stratiotes (P. stratiotes), Nymphaea spontanea (N. spontanea), Hydrilla verticillata (H. verticillata), Salvinia minima (S. minima), and Ipomoea aquatica (I. aquatica) were collected from the surrounding of Sukinda area and reared in freshwater tank for two months. The experiment was set up in two factorial completely randomized design (CRD), where equal amount of each species (65 ± 15 gm) was placed separately in clay pot containing 8.0 L water under net-house environment. Potassium chromate (K2CrO4) was used to generate 0.1, 0.5 and 1.0 mg Cr(VI)/L; and ‘no Cr(VI)’ as treatments. The fresh biomass weight of the individual plants and Cr(VI) level in the respective treatments were monitored at 18-, 22-, 30-, 40-, 47- and 54 days after initiation of the experiment. The relative growth rate (RGR) of individual species was computed as follows: where w1 and w2 are the weight of plant biomass at time t1 and t2 in days