title: Characterization of Al30 in commercial poly-aluminum chlorohydrate by solid-state (27)Al NMR spectroscopy.
abstract: Investigation of commercially produced hydrolysis salts of aluminum by solid-state (27)Al NMR spectroscopy and size-exclusion chromatography (SEC) reveals well-defined and distinct Al environments that can be related to physicochemical properties. (27)Al MAS and MQ-MAS NMR spectroscopic data show that the local structure of the solids is dominated by moieties that closely resemble the Al30 polyoxocation (Al30O8(OH)56(H2O)26(18+)), accounting for 72-85% of the total Al. These Al30-like clusters elute as several size fractions by SEC. Comparison of the SEC and NMR results indicates that the Al30-like clusters includes intact isolated clusters, moieties of larger polymers or aggregates, and possibly fragments resembling δ-Al13 Keggin clusters. The coagulation efficacy of the solids appears to correlate best with the abundance of intact Al30-like clusters and of smaller species available to promote condensation reactions.
authors.affiliation: Dept. of Geosciences, Stony Brook University, Stony Brook, NY 11794-2100, USA. Electronic address: brian.phillips@stonybrook.edu.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Phillips
authors.affiliation: Dept. of Geosciences, Stony Brook University, Stony Brook, NY 11794-2100, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Vaughn
authors.affiliation: Colgate-Palmolive Company, 909 River Road, Piscataway, NJ 08855, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Smart
authors.affiliation: Colgate-Palmolive Company, 909 River Road, Piscataway, NJ 08855, USA. Electronic address: long_pan@colpal.com.
authors.forename: Long
authors.initials: L
authors.lastname: Pan
keywords: (27)Al; Al hydrolysis; Keggin clusters; MQ-MAS; NMR; Poly-aluminum chlorohydrate