Modified ferron assay for speciation characterization of hydrolyzed Al(III): a precise k value based judgment.
WATER SCI TECHNOL
823 - 832.
The speciation of Al-OH complexes in terms of Al-a, Al-b and Al-c could be achieved by traditional ferron assay and Al-b is generally considered as Al-13, however, the inherent correlation between them remains an enigma. This paper presents a modified ferron assay to get precise determination of Al-13 using nonlinear least squares analysis, and to clarify the correlation between Alb and Al-13. Two parallel reactions conforming to pseudo-first-order kinetics can simulate the complicate reactions between polynuclear complexes and ferron successfully. Four types of experimental kinetic constant (k value) of Al-OH complexes can be observed by this method when investigating three typical aluminium solutions. Comparing with the results of Al-27 NMR, the species with moderate kinetics around 0.001 s(-1) can be confirmed to resemble to Al-13 polycation. The other types of kinetics are also well-regulated in partially neutralized aluminium solutions with various OH/Al ratios (b values) in the range 0 similar to 2.5. It would provide potential means to trace the in-situ formation of Al-13 in dilute solutions such as coagulation with Al-based coagulants
|Title:||Modified ferron assay for speciation characterization of hydrolyzed Al(III): a precise k value based judgment|
|Keywords:||Al-13, coagulation, ferron assay, hydrolyzed Al(III), speciation characterization, HYDROXYALUMINUM SOLUTIONS, POLYNUCLEAR ALUMINUM, COAGULATION, AL-13, PRECIPITATION, MONONUCLEAR, MECHANISM, CHLORIDE, SALTS, WATER|
|UCL classification:||UCL > School of BEAMS > Faculty of Engineering Science > Civil, Environmental and Geomatic Engineering|
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