کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1170409 960679 2008 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Potentiometric determination of the ‘formal’ hydrolysis ratio of aluminium species in aqueous solutions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Potentiometric determination of the ‘formal’ hydrolysis ratio of aluminium species in aqueous solutions
چکیده انگلیسی

The ‘formal’ hydrolysis ratio (h = C(OH−)added/C(Al)total) of hydrolysed aluminium-ions is an important parameter required for the exhaustive and quantitative speciation–fractionation of aluminium in aqueous solutions. This paper describes a potentiometric method for determination of the formal hydrolysis ratio based on an automated alkaline titration procedure. The method uses the point of precipitation of aluminium hydroxide as a reference (h = 3.0) in order to calculate the initial formal hydrolysis ratio of hydrolysed aluminium-ion solutions. Several solutions of pure hydrolytic species including aluminium monomers (AlCl3), Al13 polynuclear cluster ([Al13O4(OH)24(H2O)12]7+), Al30 polynuclear cluster ([Al30O8(OH)56(H2O)26]18+) and a suspension of nanoparticulate aluminium hydroxide have been used as ‘reference standards’ to validate the proposed potentiometric method. Other important variables in the potentiometric determination of the hydrolysis ratio have also been optimised including the concentration of aluminium and the type and strength of alkali (Trizma-base, NH3, NaHCO3, Na2CO3 and KOH). The results of the potentiometric analysis have been cross-verified by quantitative 27Al solution nuclear magnetic resonance (27Al NMR) measurements. The ‘formal’ hydrolysis ratio of a commercial basic aluminium chloride has been measured as an example of a practical application of the developed technique.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Analytica Chimica Acta - Volume 607, Issue 1, 21 January 2008, Pages 61–73
نویسندگان
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