کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9674165 1453199 2005 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The effect of citrate, oxalate, acetate, silicate and phosphate on stability of synthetic arsenic-loaded ferrihydrite and Al-ferrihydrite
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بهداشت و امنیت شیمی
پیش نمایش صفحه اول مقاله
The effect of citrate, oxalate, acetate, silicate and phosphate on stability of synthetic arsenic-loaded ferrihydrite and Al-ferrihydrite
چکیده انگلیسی
The effect of the organic species oxalate, citrate and acetate and the inorganic species silicate and phosphate on release of As(V) from synthetic arsenic-loaded ferrihydrite and Al-ferrihydrite in the pH range 4-8 was investigated. For ferrihydrite, the organic species increased %As(V) extraction in the order: acetate < oxalate ≪ citrate. In each case, the %As(V) extraction increased when acidity changed to pH's lower than 6, but remained unchanged when the pH increased from 6 to 8. For Al-ferrihydrite, the trend for %As release as a function of pH in the presence of acetate and oxalate was similar to that for ferrihydrite. However, unlike the ferrihydrite case, in the presence of citrate the %As extraction went through a minimum at pH 6. This is postulated to be related to the solubility equilibria of Al-ferrihydrite as a function of pH. The co-presence of silicate or phosphate with each of the organic species enhanced As(V) extraction in the order SiO32− > PO43−. Competitive adsorption of the investigated organic and inorganic species on ferrihydrite and Al-ferrihydrite could explain the enhanced release of As(V) into solution. However, disproportionate adsorption of other species relative to amount of As(V) release occurs, suggesting that mechanisms other than competitive adsorption are also operative. The results could best be explained in terms of combination of competitive adsorption and processes involving pH-dependent dissolution of ferrihydrite/Al-ferrihydrite, formation of various complex ionic species involving Al(III), Fe(III), As(V), SiO32−, PO43−, OH−, H+ and organic species: acetate, oxalate and citrate.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hazardous Materials - Volume 124, Issues 1–3, 30 September 2005, Pages 95-100
نویسندگان
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