Reduction of hexavalent chromium by ascorbic acid in aqueous solutions.
Hexavalent chromium is a priority pollutant in the USA and many other countries. Reduction of Cr(VI) to Cr(III) is environmentally favorable as the latter species is not toxic to most living organisms and also has a low mobility and bioavailability. Reduction of Cr(VI) by ascorbic acid (vitamin C) as a reductant was studied using potassium dichromate solution as the model pollutant. Effects of concentration of vitamin C, pH, temperature, irradiation and reaction time on the reduction of Cr(VI) were examined. Cr(VI) might be reduced by vitamin C not only in acidic conditions but also in weakly alkaline solutions. The reduction of Cr(VI) by vitamin C might occur not only under irradiation but also in the dark. Vitamin C is an important biological reductant in humans and animals, and not toxic. It is water-soluble and can easily permeate through various types of soils. The results indicate that vitamin C could be used in effective remediation of Cr(VI)-contaminated soils and groundwater in a wide range of pH, with or without sunlight.
Laboratory of Environmental Toxicology, Department of Ecology & Biodiversity, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, PR China.
Xiang-Rong
XR
Xu
Hua-Bin
HB
Li
Xiao-Yan
XY
Li
Ji-Dong
JD
Gu
D001205:Ascorbic Acid / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D004787:Environmental Pollution / Q000517:prevention & control*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010084:Oxidation-Reduction / Q000528:radiation effects; D013056:Spectrophotometry, Ultraviolet; D013472:Sunlight; D013696:Temperature; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*
D014867:Water; D002857:Chromium; C074702:chromium hexavalent ion; D001205:Ascorbic Acid