Green synthesis of hydrocalumite (CaAl-OH-LDH) from Ca(OH)(2)and Al(OH)(3) and the parameters that influence its formation and speciation

dc.contributor.authorGevers, Bianca R.
dc.contributor.authorLabuschagne, F.J.W.J. (Frederick Johannes Willem Jacobus)
dc.contributor.emailbianca.gevers@tuks.co.zaen_ZA
dc.date.accessioned2021-04-01T06:02:52Z
dc.date.available2021-04-01T06:02:52Z
dc.date.issued2020-08
dc.description.abstractHydrocalumite is a layered double hydroxide (LDH) that is finding increased application in numerous scientific fields. Typically, this material is produced through environmentally polluting methods such as co-precipitation, sol-gel synthesis and urea-hydrolysis. Here, the hydrothermal green (environmentally friendly) synthesis of hydrocalumite (CaAl-OH) from Ca(OH)2 and Al(OH)3 in water and the parameters that influence its formation are discussed. The parameters investigated include the reaction temperature, reaction time, molar calcium-to-aluminium ratio, the morphology/crystallinity of reactants used, mixing and the water-to-solids ratio. Hydrocalumite formation was favoured in all experiments, making up between approximately 50% and 85% of the final crystalline phases obtained. Factors that were found to encourage higher hydrocalumite purity include a low water-to-solids ratio, an increase in the reaction time, sufficient mixing, the use of amorphous Al(OH)3 with a high surface area, reaction at an adequate temperature and, most surprisingly, the use of a calcium-to-aluminium ratio that stoichiometrically favours katoite formation. X-ray diffraction (XRD) and Rietveld refinement were used to determine the composition and crystal structures of the materials formed. Scanning electron microscopy (SEM) was used to determine morphological differences and Fourier-transform infrared analysis with attenuated total reflectance (FTIR-ATR) was used to identify possible carbonate contamination, inter alia. While the synthesis was conducted in an inert environment, some carbonate contamination could not be avoided. A thorough discussion on the topic of carbonate contamination in the hydrothermal synthesis of hydrocalumite was given, and the route to improved conversion as well as the possible reaction pathway were discussed.en_ZA
dc.description.departmentChemical Engineeringen_ZA
dc.description.librarianpm2021en_ZA
dc.description.sponsorshipThis research was funded by Techsparks (Pty) Ltd and the Technology and Human Resources for Industry Programme (THRIP) administered by the Department of Trade and Industry, South Africa, (grant number THRIP/133/31/03/2016). The APC was funded by the University of Pretoria, South Africa.en_ZA
dc.description.sponsorshipTechsparks (Pty) Ltd, the Technology and Human Resources for Industry Programme (THRIP) and the University of Pretoria, South Africa.en_ZA
dc.description.urihttp://www.mdpi.com/journal/crystalsen_ZA
dc.identifier.citationGevers, B.R.; Labuschagné, F.J.W.J. Green Synthesis of Hydrocalumite (CaAl-OH-LDH) from Ca(OH)2 and Al(OH)3 and the Parameters That Influence Its Formation and Speciation. Crystals 2020, 10, 672. https://doi.org/10.3390/cryst10080672.en_ZA
dc.identifier.issn2073-4352 (online)
dc.identifier.other10.3390/cryst10080672
dc.identifier.urihttp://hdl.handle.net/2263/79148
dc.language.isoenen_ZA
dc.publisherMDPIen_ZA
dc.rights© 2020 by the authors. Licensee: MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).en_ZA
dc.subjectLayered double hydroxideen_ZA
dc.subjectAFm phaseen_ZA
dc.subjectCalcium hemicarboaluminateen_ZA
dc.subjectCement phasesen_ZA
dc.subjectCement hydrationen_ZA
dc.subjectC3AH6en_ZA
dc.subjectKatoiteen_ZA
dc.subjectLayered double hydroxide (LDH)en_ZA
dc.subjectX-ray diffraction (XRD)en_ZA
dc.subjectScanning electron microscopy (SEM)en_ZA
dc.subjectFourier-transform infrared analysis with attenuated total reflectance (FTIR-ATR)en_ZA
dc.titleGreen synthesis of hydrocalumite (CaAl-OH-LDH) from Ca(OH)(2)and Al(OH)(3) and the parameters that influence its formation and speciationen_ZA
dc.typeArticleen_ZA

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
Gevers_Green_2020.pdf
Size:
27.89 MB
Format:
Adobe Portable Document Format
Description:
Article

License bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
license.txt
Size:
1.75 KB
Format:
Item-specific license agreed upon to submission
Description: