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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume x Issue x (2006) pp 267-270

Microscale Environmental Chemistry: Part 7. Estimation of the Point of Zero Charge (pzc) for Simple Metal Oxides by a Simplified Potentiometric Mass Titration Method

Patricia Balderas-Hernandez, Jorge G. Ibanez,* Juan Jose Godinez-Ramirez, and Fernando Almada-Calvo

Centro Mexicano de Quimica en Microescala. Dept. Ing. y C. Quimicas, Universidad Iberoamericana. Prol. Reforma 880, 01210 Mexico, D.F. Mexico,
Received May 25, 2005. Accepted August 12, 2005.

Published online: 30 June 2006

Abstract. The determination of the point of zero charge (pzc) for different oxides is important for the prediction of the dependence of various properties with pH. Thus, the pzc can be used to study and characterize the specific adsorption of acids, bases, cations and anions at the water/oxide interface. There are many techniques available for the determination of the pzc, although most of them are somewhat complex. In this work we present a fast and simple pzc determination for some naturally occurring oxides (TiO2, MgO, ZnO, Al2O3, and SiO2), based on a potentiometric procedure. Here, the intersection between a titration curve of the suspended solid oxide (at constant ionic strength) and that of a blank solution (i.e., without the solid) corresponds to the pzc. The values thus obtained are comparable to those reported in the literature.

Key Words: Laboratories and Demonstrations; general chemistry; analytic chemistry; electrochemistry; inorganic chemistry

(*) Corresponding author. (E-mail:

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Issue date: August 1, 2006

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