Potentiometric determination of the 'formal' hydrolysis ratio of aluminium species in aqueous solutions.

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.

Interactions of bovine serum albumin with aluminum polyoxocations and aluminum hydroxide.

Interactions of aqueous solutions of aluminum polyoxocations (Al13-mers and Al30-mers) and aluminum hydroxide suspensions of varying particle sizes (26, 55, and 82 nm) with a model protein, bovine serum albumin (BSA), have been investigated using potentiometry, conductometry, viscometry, 27Al solution NMR, UV-vis spectroscopy, dynamic light scattering, zeta-potential measurements, thermogravimetry, X-ray diffraction, and scanning electron microscopy. Increasing amounts of BSA partially convert Al13-mers and, to a larger extent, Al30-mers into amorphous Al hydroxide without gel formation. At the same time, BSA molecules can form unstable aggregates in the Al polyoxocation solutions which redisperse easily upon standing.

A systematic investigation of aluminium ion speciation at high temperature. Part 1. Solution studies.

Speciation diagrams of aluminium ions in aqueous solution (0.2 M) at high temperature (90 degrees C) have been obtained from 48 h time-resolved multi-batch titration experiments monitored by 27Al NMR spectroscopy, potentiometry and dynamic light scattering. The quantitative speciation patterns and kinetic data obtained offer a dynamic picture of the distribution of soluble and insoluble Al species as a function of hydrolysis ratio h(h=[OH-]/[Al3+]) over a very broad range of conditions (-1.