Determination of the dependence of the structure of Zn-Al layered double hydroxides, as a matrix for functional anions intercalation, on synthesis conditions
| Autor: | Vadym Kovalenko, Anastasiia Borysenko, Valerii Kotok, Rovil Nafeev, Volodymyr Verbitskiy, Olena Melnyk |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
intercalation
nitrate Control and Systems Engineering Applied Mathematics Management of Technology and Innovation Mechanical Engineering Zn-Al layered double hydroxide Energy Engineering and Power Technology Electrical and Electronic Engineering crystallinity Industrial and Manufacturing Engineering X-ray diffraction Computer Science Applications |
| Zdroj: | Eastern-European Journal of Enterprise Technologies. 1:12-20 |
| ISSN: | 1729-4061 1729-3774 |
| DOI: | 10.15587/1729-4061.2022.252738 |
| Popis: | Layered double hydroxides, especially Zn-Al, are valuable matrices for intercalation with various functional anions: dyes, medicines, food additives, etc. For the purposeful development and optimization of the technology for the synthesis of Zn-Al hydroxides intercalated with functional anions, the phase composition and crystal structure of Zn-Al nitrate layered double hydroxide samples (Zn:Al=4:1) synthesized at solution flow rates of 0.8 and 1.6 l/h, pH=7, 8, 9, 10 and t=10, 20, 30, 40, 50 and 60 °С were studied. XRD showed that all samples synthesized at different temperatures, pH, and solution flow rates were Zn-Al layered double hydroxides with an α-Zn(OH)2crystal lattice of medium crystallinity, with an admixture of an oxide phase with a ZnO lattice. Three sections of the dependence of the crystallite size of the sample on the synthesis temperature were distinguished: 10–20°C, 30–50°C, and 60°C, within which an increase in temperature led to an increase in crystallinity. A hypothesis was put forward about a change in the mechanism or kinetics of LDH formation at temperatures of 30°C and 60°C. An increase in the pH of the synthesis and the flow rate of solutions led to an increase in crystallinity. A retrospective comparative analysis of the phase composition and crystal structure of Zn-Al-nitrate and Zn-Al-tripolyphosphate (tartrazine or Orange Yellow S) LDH samples was carried out. It was found that the use of large and multi-charged functional anions caused significant adsorption on precipitate nuclei and difficult intercalation. As a result, low crystallinity was formed (Tartrazine anion) or a significant part of LDH was decomposed to oxide (tripolyphosphate and Orange Yellow S anions). |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|