Temperature Effect on the Surface Charge Properties of γ-Al2O3

✍ Scribed by S. Mustafa; B. Dilara; Z. Neelofer; A. Naeem; S. Tasleem

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 208 KB
• Volume: 204
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1998.5572

✦ Synopsis

constants pK a1 , pK a2 , pK an , pK cat , and point of zero charge A comprehensive study of the surface properties of the g-Al 2 O 3 (PZC) of the oxides/hydroxides. Generally in the literature in KNO 3 as a function of temperature was undertaken potentio- , all these pK values were found to decrease with the metrically. Surface charge, ionization and complexation constants, increase in temperature; however, Akratopulu et al. (5) oband PZC were calculated from the potentiometric titration data served an increase in the pK a1 and pK a2 values of g-Al 2 O 3 . in the temperature range 293-333 K. A difference between the As such, no unified view regarding the effect of temperature PZC and CIP was observed as a result of the adsorption of on the surface ionization constants is available in the literature. NO 0 3 ions. A simple graphical procedure based on the mass action The present study, therefore, deals with the determination of law was used to determine the number of surface sites and equilib-PZC of g-Al 2 O 3 , ionization and complexation constants and rium constants. Thermodynamic parameters, which showed a decrease in the role of nitrate NO 0

3 ion in the charging mechanism various thermodynamic parameters in 0.001-0.1 molrdm 03 of g-Al 2 O 3 , were also evaluated, whereas that of K / ion increased KNO 3 solutions in the temperature range 293-333 K.

with the increase in temperature.