Determination of Point of Zero Charge of Tunisian Kaolinites by Potentiometric and Mass Titration Methods
作者:
A. Kriaa,
N. Hamdi,
E. Srasra,
期刊:
Journal of the Chinese Chemical Society
(WILEY Available online 2008)
卷期:
Volume 55,
issue 1
页码: 53-61
ISSN:0009-4536
年代: 2008
DOI:10.1002/jccs.200800010
出版商: WILEY‐VCH Verlag
关键词: Kaolinite;Mass titration;Potentiometric titration;Point of zero net proton charge;Proton surface charge
数据来源: WILEY
摘要:
AbstractThis paper deals with determining points of zero charge of natural and Na+‐saturated mineral kaolinites using two methods: (1) acid‐base potentiometric titration was employed to obtain the adsorption of H+and OH−on amphoteric surfaces in solutions of varying ionic strengths in order to determinate graphically the point of zero net proton charge (PZNPC) defined equally as point of zero salt effect (PZSE); (2) mass titration curve at different electrolyte concentrations in order to estimate PZNPCs by interpolation and to compare with those determined by potentiometric titrations. The two methods involved points of zero charge approximately similar for the two kaolinites between 6.5‐7.8, comparable to those reported previously and were in the range expected for these clay minerals. The comparison of potentiometric surface titration curves obtained at 25 °C and those published in the literature reveals significant discrepancies both in the shape and in the pH of PZNPC
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