Role of Phosphate Species and Speciation Kinetics in Detergency Solutions

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• 作者：Giulio Isacco Lampronti ; Gilberto Artioli ; Liliana Oliva ; Alessandro Ongaro ; Stefano Maretto ; Francesca Bonino ; Katia Barbera ; Silvia Bordiga
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：March 21, 2012
• 年：2012
• 卷：51
• 期：11
• 页码：4173-4180
• 全文大小：445K
• 年卷期：v.51,no.11(March 21, 2012)
• ISSN：1520-5045

文摘

The present investigation addresses the mechanisms of inorganic phases precipitation from detergency solutions of low polyphosphate formulation. In washing machine systems the main precipitation agent is Na₄P₂O₇路10H₂O that constitutes up to 10 wt % commercial Na₅P₃O₁₀路5H₂O. The solid incrustation on the heating coil is mainly formed by amorphous calcium pyrophosphate, subsequently transforming first into amorphous calcium orthophosphate and then into low crystallinity hydroxylapatite. The tripolyphosphate eventually present in the precipitates hydrolyzes as well at the working temperature present at the surface of the washing machine coil (100 掳C). The pyrophosphate presence strongly inhibits the crystallization of hydroxylapatite in the washing system; thus, thermal treatment of amorphous calcium鈥損yrophosphate is a viable mechanism to produce hydroxylapatite with controlled crystallinity. A range of analytical techniques including X-ray diffraction, IR spectroscopy, and liquid- and solid-state NMR were employed to quantify the speciation kinetics in solution, to characterize the nature of the precipitates, and to monitor the phase transformations in the solid.