کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4700677 1637722 2008 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Sorption of As(III) and As(V) to siderite, green rust (fougerite) and magnetite: Implications for arsenic release in anoxic groundwaters
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Sorption of As(III) and As(V) to siderite, green rust (fougerite) and magnetite: Implications for arsenic release in anoxic groundwaters
چکیده انگلیسی

The formation of secondary Fe(II) or mixed Fe(II)/Fe(III) minerals such as siderite, green rust (fougerite) and magnetite has been suggested to reduce the aqueous concentration of Fe while leaving the concentration of As high in the Bangladesh and West Bengal aquifers. To test this hypothesis we have studied the adsorption of arsenite and arsenate to siderite, fougerite and magnetite using batch sorption experiments and EXAFS spectroscopy. We find that As(V) sorbs to fougerite, magnetite, and siderite by forming inner-sphere surface complexes resulting from corner sharing between AsO4 groups and FeO6 octahedra. No evidence of As(V) reduction is found. As(III) also forms inner-sphere surface complexes on magnetite and fougerite but only a (presumably) weak outer-sphere complex on siderite. No evidence for As(III) oxidation is found. As(V) desorbs from magnetite, fougerite and siderite at pH > 8; however, As(III) sorption to all three phases is enhanced with increasing pH. Hence, dissimilatory reduction of iron oxides, followed by precipitation of fougerite, magnetite or siderite will released dissolved As(V) at pH > 8; however, if As(V) is also reduced to As(III), sorption of As will be enhanced.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 255, Issues 1–2, 30 September 2008, Pages 173–181
نویسندگان
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