The effectiveness of ferrous iron and sodium dithionite for decreasing resin-extractable Cr(VI) in Cr(VI)-spiked alkaline soils

JOURNAL OF HAZARDOUS MATERIALS

卷:164

Article

Cheng, Chia-Jung¹  Lin, Tzu-Huei¹  Chen, Chiou-Pin¹  Juang, Kai-Wei²  Lee, Dar-Yuan¹ 

[1] Natl Taiwan Univ, Dept Agr Chem, Taipei 10764, Taiwan

[2] Ming Dao Univ, Dept Post Modern Agr, Changhua, Taiwan

关键词: Cr(VI)-spiked alkaline soils;    Cr(VI) reduction;    Ferrous iron;    Sodium dithionite;    Resin-extractable Cr(VI);   

DOI  :  10.1016/j.jhazmat.2008.08.037

来源: Elsevier

【 摘 要 】

Ferrous iron. Na2S2O4, and a mixture of Fe(II) and Na2S2O4 (4:1 mol/mol) were tested for their effectiveness for decreasing resin-extractable Cr(VI) in alkaline Cr(VI)-spiked soils. The results indicated that adding those reductants greatly decreased the amount of resin-extractable Cr(VI) when the application rate of reductants equaled the number of equivalents of dichromate added to the Cr(VI)-spiked soils. This was mainly as a result of the Cr(VI) reduction into Cr(III), as supported by the XANES spectra. Among the tested reductants, a mixture of Fe(II) and Na2S2O4 was the most effective to decrease resin-extractable Cr(VI). The extent to which resin-extractable Cr(VI) and soil pH were decreased was affected by the pH of the reductants. Among the tested reductants at various pH, FeSO4 at pH below 1 was the most effective in decreasing resin-extractable Cr(VI) in alkaline soils. However, the soil pH was the most decreased as well. On the other hand, the mixtures of ferrous iron and dithionite at a wide range of pH were all efficient (>70% efficiency) in decreasing resin-extractable Cr(VI). Moreover, the extent of the decrease in soil pH was much smaller than that by FeSO4 (pH < 1) alone, and thus the possibility of the Cr(III) hazard can be avoided. (C) 2008 Elsevier B.V. All rights reserved.

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