Effect of Hofmeister Anions on Interfacial Properties of Mica Surface in Concentrated Aqueous Solution
Open Access
- 9 September 2020
- Vol. 10 (9), 872
- https://doi.org/10.3390/coatings10090872
Abstract
The electric double layer (EDL) formed at the water/solid interface is the key to understanding a wide variety of natural phenomena; and nowadays, this knowledge may lead to ideas for technological innovations in the industrial and biomedical fields. The properties of the EDL on a surface directly determine the performance of an EDL-based device. In electrolyte solution, the coions with the same charge sign with the surface are usually ignored. However, they are expected to make a considerable contribution in concentrated conditions when ionic specific effects should be considered. Herein, we investigated the effect of anions in the Hofmeister series, including kosmotropes (Ac−), chaotropes (I−), and intermediate (Cl−), on the properties of the EDL on a negatively charged mica surface by observing intersurface forces using the surface forces apparatus (SFA). The SFA results indicated that at a concentration of 1 M and above, the effect of the monovalent anions in the sodium solutions were mainly correlated with their hydration behaviors. Exclusively in the solutions with strongly hydrated anions, we measured the abnormal long-range repulsions in the diffuse layer region farther away from the surface. By further investigating the solutions with kosmotropic divalent SO42− at relatively low concentrations, we may attribute the observation to the formation of ion pairs and hydrodynamic effects in the presence of concentrated kosmotropic anions. Moreover, these anions can also contribute to the formation of a complete and stable hydration layer near the surface. This work demonstrates the considerable effects of Hofmeister anionic coions on the properties of a simple colloid interface, which has attracted little attention in the past. Therefore, further investigations are desirable in the development of electrolytes and surface materials for the promising EDL-based technologies.Keywords
Funding Information
- National Natural Science Foundation of China-Guangdong Joint Fund (51605090)
- Fundamental Research Funds for Central Universities of the Central South University (2242019k1G011)
- Natural Science Foundation of Jiangsu Province (BK20160670, BK20180400)
This publication has 72 references indexed in Scilit:
- Design and optimization of electrochemical cell potential for hydrogen gas productionJournal of Energy Chemistry, 2020
- Electrochemical study of different membrane materials for the fabrication of stable, reproducible and reusable reference electrodeJournal of Energy Chemistry, 2020
- Electrochemical investigation of novel reference electrode Ni/Ni(OH)₂ in comparison with silver and platinum inert quasi-reference electrodes for electrolysis in eutectic molten hydroxideInternational Journal of Hydrogen Energy, 2019
- The Electrostatic Screening Length in Concentrated Electrolytes Increases with ConcentrationThe Journal of Physical Chemistry Letters, 2016
- A review on electrochemical double-layer capacitorsEnergy Conversion and Management, 2010
- Capacitive deionization (CDI) for desalination and water treatment — past, present and future (a review)Desalination, 2008
- Control of aggregation in production and handling of nanoparticlesChemical Engineering and Processing - Process Intensification, 2005
- Ion sensitive field effect transducer-based biosensorsBiotechnology Advances, 2003
- Electric double layer interactions in bacterial adhesion to surfacesSurface Science Reports, 2002
- The swelling behaviour of claysApplied Clay Science, 1989