1
|
Katana B, Takács D, Szerlauth A, Sáringer S, Varga G, Jamnik A, Bobbink FD, Dyson PJ, Szilagyi I. Aggregation of Halloysite Nanotubes in the Presence of Multivalent Ions and Ionic Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11869-11879. [PMID: 34601883 PMCID: PMC8515846 DOI: 10.1021/acs.langmuir.1c01949] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Colloidal stability was investigated in two types of particle systems, namely, with bare (h-HNT) and polyimidazolium-functionalized (h-HNT-IP-2) alkali-treated halloysite nanotubes in solutions of metal salts and ionic liquids (ILs). The valence of the metal ions and the number of carbon atoms in the hydrocarbon chain of the IL cations (1-methylimidazolium (MIM+), 1-ethyl-3-methylimidazolium (EMIM+), 1-butyl-3-methylimidazolium (BMIM+), and 1-hexyl-3-methylimidazolium (HMIM+)) were altered in the measurements. For the bare h-HNT with a negative surface charge, multivalent counterions destabilized the dispersions at low values of critical coagulation concentration (CCC) in line with the Schulze-Hardy rule. In the presence of ILs, significant adsorption of HMIM+ took place on the h-HNT surface, leading to charge neutralization and overcharging at appropriate concentrations. A weaker affinity was observed for MIM+, EMIM+, and BMIM+, while they adsorbed on the particles to different extents. The order HMIM+ < BMIM+ < EMIM+ < MIM+ was obtained for the CCCs of h-HNT, indicating that HMIM+ was the most effective in the destabilization of the colloids. For h-HNT-IP-2 with a positive surface charge, no specific interaction was observed between the salt and the IL constituent cations and the particles, i.e., the determined charge and aggregation parameters were the same within experimental error, irrespective of the type of co-ions. These results clearly indicate the relevance of ion adsorption in the colloidal stability of the nanotubes and thus provide useful information for further design of processable h-HNT dispersions.
Collapse
Affiliation(s)
- Bojana Katana
- MTA-SZTE
Lendület Biocolloids Research Group, Interdisciplinary Excellence
Center, Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Dóra Takács
- MTA-SZTE
Lendület Biocolloids Research Group, Interdisciplinary Excellence
Center, Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Adél Szerlauth
- MTA-SZTE
Lendület Biocolloids Research Group, Interdisciplinary Excellence
Center, Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Szilárd Sáringer
- MTA-SZTE
Lendület Biocolloids Research Group, Interdisciplinary Excellence
Center, Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Gábor Varga
- Material
and Solution Structure Research Group, Department of Organic Chemistry, University of Szeged, H-6720 Szeged, Hungary
| | - Andrej Jamnik
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Felix D. Bobbink
- Institute
of Chemical Sciences and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Paul J. Dyson
- Institute
of Chemical Sciences and Engineering, École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Istvan Szilagyi
- MTA-SZTE
Lendület Biocolloids Research Group, Interdisciplinary Excellence
Center, Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| |
Collapse
|
2
|
Katana B, Takács D, Csapó E, Szabó T, Jamnik A, Szilagyi I. Ion Specific Effects on the Stability of Halloysite Nanotube Colloids-Inorganic Salts versus Ionic Liquids. J Phys Chem B 2020; 124:9757-9765. [PMID: 33076658 PMCID: PMC7660744 DOI: 10.1021/acs.jpcb.0c07885] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/09/2020] [Indexed: 11/30/2022]
Abstract
Charging and aggregation processes were studied in aqueous dispersions of halloysite nanotubes (HNTs) in the presence of monovalent inorganic electrolytes and ionic liquid (IL) constituents. The same type of co-ion (same sign of charge as HNT) was used in all systems, while the type of counterions (opposite sign of charge as HNT) was systematically varied. The affinity of the inorganic cations to the HNT surface influenced their destabilizing power leading to an increase in the critical coagulation concentration (CCC) of HNT dispersions in the Cs+ < K+ < Na+ order. This trend agrees with the classical Hofmeister series for negatively charged hydrophobic surfaces. For the IL cations, the CCCs increased in the order BMPY+ < BMPIP+ < BMPYR+ < BMIM+. An unexpectedly strong adsorption of BMPY+ cations on the HNT surface was observed giving rise to charge neutralization and reversal of the oppositely charged outer surface of HNT. The direct Hofmeister series was extended with these IL cations. The main aggregation mechanism was rationalized within the classical theory developed by Derjaguin, Landau, Verwey, and Overbeek, while ion specific effects resulted in remarkable variation in the CCC values. The results unambiguously proved that the hydration level of the surface and the counterions plays a crucial role in the formation of the ionic composition at the solid-liquid interface and consequently, in the colloidal stability of the HNT particles in both inorganic salt and IL solutions.
Collapse
Affiliation(s)
- Bojana Katana
- MTA-SZTE
Lendület Biocolloids Research Group and Interdisciplinary Excellence Center,
Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Dóra Takács
- MTA-SZTE
Lendület Biocolloids Research Group and Interdisciplinary Excellence Center,
Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Edit Csapó
- MTA-SZTE
Lendület Biocolloids Research Group and Interdisciplinary Excellence Center,
Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Tamás Szabó
- MTA-SZTE
Lendület Biocolloids Research Group and Interdisciplinary Excellence Center,
Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| | - Andrej Jamnik
- Faculty
of Chemistry and Chemical Technology, University
of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Istvan Szilagyi
- MTA-SZTE
Lendület Biocolloids Research Group and Interdisciplinary Excellence Center,
Department of Physical Chemistry and Materials Science, University of Szeged, H-6720 Szeged, Hungary
| |
Collapse
|