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Piasecki W, Lament K. Application of Potentiometric and Electrophoretic Measurements to Evaluate the Reversibility of Adsorption of Divalent Ions from a Solution on Titanium Dioxide. Molecules 2024; 29:555. [PMID: 38338300 PMCID: PMC11154309 DOI: 10.3390/molecules29030555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
The adsorption of divalent ions on metal oxides is controlled by the pH of a solution. It is commonly assumed that this is a reversible process for pH changes. However, there are reports that the sorption of ions on oxides may not be reversible. To verify this, we used potentiometric titration, ion-selective electrodes (ISEs), and electrokinetic measurements to examine the reversibility of the adsorption of hydrogen ions and three metal ions (Ca2+, Cu2+, and Fe2+) on TiO2. The ferrous ion was used as a reference because its adsorption is entirely irreversible. The surface charge determined by potentiometric titration and the adsorption edges measured using ISE indicate that the adsorption of copper ions is reversible with changes in pH. In the case of calcium ions, the results suggest a certain degree of irreversibility. There are apparent differences in the electrokinetic potential data obtained during titration with base and acid, which suggests that the adsorption is irreversible. We have explained this contradiction by considering the complex and dynamic nature of electrophoretic mobility. In our opinion, potentiometric titration may be the simplest and most reliable method for assessing the reversibility of multivalent ion adsorption.
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Affiliation(s)
- Wojciech Piasecki
- Department of Physical Education and Health, Józef Piłsudski University of Physical Education in Warsaw, Akademicka 2, 21-500 Biała Podlaska, Poland;
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Kammerer JA, Feist F, Ryklin D, Sarkar A, Barner-Kowollik C, Schröder RR. Direct Visualization of Homogeneous Chemical Distribution in Functional Polyradical Microspheres. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211074. [PMID: 36639825 DOI: 10.1002/adma.202211074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/05/2023] [Indexed: 06/17/2023]
Abstract
It is demonstrated that the postfunctionalization of solid polymeric microspheres can generate fully and throughout functionalized materials, contrary to the expectation that core-shell structures are generated. The full functionalization is illustrated on the example of photochemically generated microspheres, which are subsequently transformed into polyradical systems. Given the all-organic nature of the functionalized microspheres, characterization methods with high analytical sensitivity and spatial resolution are pioneered by directly visualizing the inner chemical distribution of the postfunctionalized microspheres based on characteristic electron energy loss signals in transmission electron microscopy (TEM). Specifically, ultrasonic ultramicrotomy is combined successfully with electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) during TEM. These findings open a key avenue for analyzing all-organic low-contrast soft-matter material structures, while the specifically investigated system concomitantly holds promise as an all-radical solid-state functional material.
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Affiliation(s)
- Jochen A Kammerer
- 3DMM2O, Cluster of Excellence (EXC-2082/1-390761711) and Cryo Electron Microscopy, BioQuant, Heidelberg University and University Hospital, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany
- School of Chemistry and Physics, Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
| | - Florian Feist
- 3DMM2O, Cluster of Excellence (EXC-2082/1-390761711) and Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Daniel Ryklin
- 3DMM2O, Cluster of Excellence (EXC-2082/1-390761711) and Cryo Electron Microscopy, BioQuant, Heidelberg University and University Hospital, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany
| | - Abhishek Sarkar
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- KIT-TUD Joint Research Laboratory Nanomaterials-Technische Universität Darmstadt, Otto-Berndt-Str. 3, 64287, Darmstadt, Germany
| | - Christopher Barner-Kowollik
- School of Chemistry and Physics, Centre for Materials Science, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD 4000, Australia
- 3DMM2O, Cluster of Excellence (EXC-2082/1-390761711) and Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Rasmus R Schröder
- 3DMM2O, Cluster of Excellence (EXC-2082/1-390761711) and Cryo Electron Microscopy, BioQuant, Heidelberg University and University Hospital, Im Neuenheimer Feld 267, 69120, Heidelberg, Germany
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