title: Direct and indirect identification of the formation of hydroxyaluminosilicates in acidic solutions.
abstract: Morin-aluminium fluorescence and membrane filtration were successfully applied to the indirect identification of the formation of hydroxyaluminosilicates (HAS) in acidic solutions of varying pH and of known concentrations of aluminium (Al) and silicic acid (Si(OH)(4)). It was proven to be especially useful in providing evidence of the strong competition between Si(OH)(4) and Al(OH)(3) to condense with hydroxyaluminium templates to form HAS in preference to Al(OH)(3(s)). The aggregation and stability of HAS and Al(OH)(3(s)) were dependent upon both the pH and the [Al] of the solution. The applicability of these indirect techniques was confirmed using the direct observation of HAS in solution by atomic force microscopy (AFM). AFM was also a powerful tool in providing valuable information on the morphology of colloidal HAS of various structures and stoichiometries. The results have provided further confirmation of both the mechanism of HAS formation and the form and stability of HAS in solution. This information is essential to our understanding of the biological availability and hence toxicity of Al in biota, including man.
authors.affiliation: Birchall Centre for Inorganic Chemistry and Materials Science, School of Chemistry and Physics, Keele University, Keele, Staffordshire ST5 5BG, UK.
authors.forename: F J
authors.initials: FJ
authors.lastname: Doucet
authors.forename: M E
authors.initials: ME
authors.lastname: Rotov
authors.forename: C
authors.initials: C
authors.lastname: Exley
mesh_terms: D000143:Acids / Q000737:chemistry*; D000535:Aluminum / Q000032:analysis / Q000737:chemistry; D000538:Aluminum Silicates / Q000032:analysis* / Q000737:chemistry*; D011232:Chemical Precipitation; D003102:Colloids / Q000737:chemistry; D005374:Filtration / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D018625:Microscopy, Atomic Force; D015203:Reproducibility of Results; D012996:Solutions / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D000143:Acids; D000538:Aluminum Silicates; D003102:Colloids; D012996:Solutions; C049037:aluminosilicate; D000535:Aluminum