کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
150201 456446 2012 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Solubility product (Ksp)-controlled removal of chromate and phosphate by hydrocalumite
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Solubility product (Ksp)-controlled removal of chromate and phosphate by hydrocalumite
چکیده انگلیسی

It has been revealed that hydrocalumite (Ca2Al–Cl–LDH) removes Cr (VI) via anion-exchange while P via dissolution–reprecipitation. In current work, the intercalation of Cr (VI) was relative to the remaining LDH, which resulted in the increase of Cr (VI) removal amount with increasing pH. In contrast, more Ca5(PO4)3OH was precipitated at initial pH 5.0 in the case of P removal, which was attributed to more hydrocalumite dissolved at such low pH. Moreover, the composition of the final solution in each case provided the evaluation of free ionic concentrations product (CP) which demonstrates that the formation of product was related to its CP value that was higher than or close to the corresponding Ksp. As Ca5(PO4)3OH or LDH–CrO4 has the lowest solubility product (Ksp) among all possible solid in each case, our results propose that the removal process of chromate and phosphate over hydrocalumite was controlled by Ksp of the product.

Chromate was intercalated into hydrocalumite via anion exchange to form LDH–CrO4, while phosphate was removed to form hydroxyapatite by dissolution–reprecipitation. The different removal processes of chromate and phosphate over hydrocalumite were controlled by the solubility product (Ksp) of final products.Figure optionsDownload as PowerPoint slideHighlights
► We examined the removal behaviors of P and Cr (VI) over hydrocalumite.
► Hydrocalumite removed Cr (VI) via anion-exchange while P via dissolution–reprecipitation.
► More Cr (VI) was intercalated to form LDH–CrO4 at high initial pH (9.0).
► More P was precipitated in hydroxyapatite at low initial pH (5.0).
► The different removal mechanisms were controlled by the solubility product (Ksp) of final products.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Journal - Volumes 181–182, 1 February 2012, Pages 251–258
نویسندگان
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