Comparison of Different Methods for the Point of Zero Charge Determination of NiO

作者：Tahira Mahmood, Muhammad Tahir Saddique, Abdul Naeem, Paul K. Westerhoff, Syed Khalid Mustafa, Absar Alum · 发表于：Industrial & Engineering Chemistry Research · 年份：2011 · DOI：10.1021/ie200271d · 被引用次数：493 · 研究领域：Electrochemical Analysis and Applications、Analytical Chemistry and Sensors、Gas Sensing Nanomaterials and Sensors

Four methods, fast titration, salt addition, mass titration, and ζ potentiometry, were employed to determine the point of zero charge (PZC) and isoelectric point (IEP) of NiO. However, this work mainly focuses on the fast titration method because it limits the release of Ni from the substrate. Furthermore, the fast titration is simple, rapid, and accurate and requires a small quantity of substrate as compared to the salt addition and mass titration techniques. The similarity between the PZC and IEP values rules out the specific adsorption of the bulk electrolyte onto the NiO surface. However, the PZC values shift downward with the increase in Cd ion concentration, which indicates the specific adsorption of Cd onto the NiO. In addition, temperature has a mild effect on the deprotonation constants and PZC of NiO. It was also observed that the thermodynamic parameters favor the deprotonation of NiO.