Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/44625
標題: The adsorption and catalytic transformations of chromium on Mn substituted goethite
作者: Wu, W.C.
王尚禮
Wang, S.L.
Tzou, Y.M.
Chen, J.H.
Wang, M.K.
鄒裕民
陳仁炫
關鍵字: chromium
Mn-substituted goethite
oxidation reaction
photo-reduction
reaction
hexavalent chromium
photocatalytic reduction
synthetic goethite
cr(vi) reduction
oxidation
manganese
soils
acid
kinetics
system
期刊/報告no:: Applied Catalysis B-Environmental, Volume 75, Issue 3-4, Page(s) 272-280.
摘要: Goethite widely occurs in the environment and its role in photoreduction of toxic Cr(VI) to less toxic Cr(III) has been previously reported in the literature. However, natural goethite is rarely stoichiometric and usually contains certain substitutional cations, such as Mn(III) or Mn(IV), which, on the other hand. is an oxidant for Cr(III). In order to provide more insight into the fate of Cr(VI) in the environment, the influence of Mn-substitution in goethite on its Cr(VI) photoreduction capability needs to be clarified. The objectives of this study were to evaluate the adsorption and photo-transformations of Cr on Mn-substituted goethite with Mn/(Mn + Fe) molar ratios ranging from 0 to 0.1. The results showed that Cr adsorption and photo-catalytic transformation on goethite were strongly influenced by the Mn content of goethite. When the system was under illumination. Cr(VI) reduction was decreased with increasing Mn-substitution in goethite. The re-oxidation of photo-reduced product, i.e., Cr(III), at the Mn sites on the surface of goethite is responsible for the lower Cr(VI) photo-reduction capacity of Mn-substituted goethite. The role of goethite in the reduction of Cr(VI) may be overestimated unless its Mn-substituted counterparts are considered. The effectiveness of Mn sites in to increase toxic Cr(VI) has important implications in determining the fate and threat of Cr(VI) contamination. (c) 2007 Elsevier B.V. All rights reserved.
URI: http://hdl.handle.net/11455/44625
ISSN: 0926-3373
文章連結: http://dx.doi.org/10.1016/j.apcatb.2007.04.026
Appears in Collections:土壤環境科學系

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