Potentiometric determination of the ‘formal’ hydrolysis ratio of aluminium species in aqueous solutions

Effect of pH on the aluminum salts hydrolysis during coagulation process: Formation and decomposition of polymeric aluminum species

“…In MS/MS spectra, [Al 3 O 4 (H 2 O)] + may lose aluminum to produce dimeric ions (m/z 103 and 121). This is consistent with previous work reported by Sarpola 4 ] + could combine together, and produced daughter ions at m/z 232 and 268. Moreover, one (three) aluminum(s) may be removed from O 17 ] 2+ , while the Al 13 structure also could be rid of three or five aluminum molecules.…”

“…It is different from Sarpola et al [12] reported that Al 13 core was highly stable, and to break its structure required very high collision energies (75 eV). The reason may be that the new formed Al 13 species in this study were not stable as aged Al 13 4 ] 2+ lost or added water molecule(s) to produce series of daughter ions at m/z 313, 331 and 367. At higher sample cone voltage (150 V), aluminum species were simplified.…”

“…Many analytical methods have been used to characterize and quantify aluminum species. Traditional methods include potentiometric titration [4], Al-ferron timed spectrophotometric assay [5,6] and 27 Al NMR spectroscopy [7,8]. In addition, X-ray diffraction [9] and Raman spectroscopy [10] are used as aluminum speciation analysis.…”

Aluminum speciation of coagulants with low concentration: Analysis by electrospray ionization mass spectrometry

“…Many analytical methods have been used to characterize and quantify aluminum species. Traditional methods include potentiometric titration [4], Al-Ferron timed spectrophotometric assay [5,6] and 27 Al nuclear magnetic resonance ( 27 Al NMR) spectroscopy [7,8]. In addition, X-ray diffraction [9], Raman spectroscopy [10] and X-ray photoelectron spectroscopy [11] are used as aluminum speciation analysis.…”

“…Al-Ferron assay and 27 Al NMR spectroscopy were common means to identify aluminum speciation of coagulant. 27 Al NMR spectroscopy offers information about monomeric, dimeric aluminum species and highly symmetric Keggin-Al 13 (K-Al 13 , AlO 4 Al 12 (OH) 24 (H 2 O) 12 7+ ) species [12]. However, investigations on speciation of aluminum salts at low concentrations in nature and coagulation are hampered by the detection limits of 27 Al NMR.…”