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Determination of Point of Zero Charge of Tunisian Kaolinites by Potentiometric and Mass Titration Methods
Author(s) -
Kriaa A.,
Hamdi N.,
Srasra E.
Publication year - 2008
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200800010
Subject(s) - potentiometric titration , chemistry , gran plot , titration , point of zero charge , titration curve , analytical chemistry (journal) , electrolyte , ionic strength , zero point energy , adsorption , inorganic chemistry , ion , chromatography , aqueous solution , physics , electrode , organic chemistry , quantum mechanics
This 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 PZNPCs values.