Stabilization of chromium(VI) by hydroxysulfate green rust in chromium(VI)-contaminated soils

摘要: Abstract Chromium (Cr)-contaminated soils pose a great environmental risk, with high solubility and persistent leaching of Cr(VI). In this study, hydroxysulfate green rust (GRSO4), the general formula Fe(II)4Fe(III)2(OH)12SO4·8H2O, was evaluated for its efficiency in Cr(VI) stabilization via reduction to Cr(III) four representative Cr(VI)-spiked soils. The initial concentrations phosphate buffer-extractable (Cr(VI)b) 1, 2, 3, 4 were 382.4, 575.9, 551.3, 483.7 mg kg–1, respectively. Reduction by structural Fe(II) (Fe(II)s) GRSO4 all studied fast, wherein application markedly decreased amount Cr(VI)b at Cr(VI)b/Fe(II)s stoichiometric mole ratio 0.33. kinetics could not be determined as reaction coincided release from soil during experiment. concentration decreased, 0.46 0.20, generally below 10 kg–1. Back-transformation generated examined presence manganese oxide birnessite birnessite/initial 4.5. results batch tests showed that only 5.2% converted after two months, while under field capacity moisture conditions, less than 0.05% oxidized six months. illustrated remediation Cr(VI)-contaminated would successful, irreversible an appropriate quantity fresh GRSO4.