Quantification by Powder X-ray Diffraction of Metal Oxides Segregation During Formation of Layered Double Hydroxides

Misol, Alexander; Jiménez, Alejandro; Morato, A.; Labajos, F.M.; Rives, V.

doi:10.24018/ejeng.2020.5.10.2192

Cited by 1 publication

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“…Comparing the width of the diffraction peaks (003) of the samples subjected to a longer treatment time (samples with 7 days of treatment) the following decreasing order of crystallinity can be established as a function of the amine used: ZA2TEAHT7 > ZA2DEAHT7. Table 2 shows the amount of zincite phase present in the sample calculated from the calibration line with the ratio of the areas of the characteristic peaks of the zincite phase and the LDH phase [35]. Thus, it is shown how the amount of zincite phase increased as the HT treatment time increased, finding an amount of approximately 2% of ZnO in the sample ZA2DEAHT7.…”

Section: Powder X-ray Diffraction (Pxrd)mentioning

confidence: 94%

Use of Ethylamine, Diethylamine and Triethylamine in the Synthesis of Zn,Al Layered Double Hydroxides

2022

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Amines with two carbon atoms in the organic chain [ethylamine (EA), diethylamine (DEA), triethylamine (TEA)] have been used as precipitant agents to obtain a hydrotalcite-like compound with Zn (II) and Al (III) as layered cations and with nitrate anions in the interlayered region to balance the charge. This Layered Double Hydroxide was prepared following the coprecipitation method, and the effect on the crystal and particle sizes was studied. Also, the effect of submitting the obtained solids to hydrothermal post-synthesis treatment by conventional heating and microwave assisted heating were studied. The obtained solids were exhaustively characterized using several instrumental techniques, such as X-ray diffraction, Thermal Analysis (DTA and TG), Chemical Analysis, Infrared Spectroscopy (FT-IR), determination of Particle Size Distribution and BET-Surface area. Well crystallized solids were obtained showing two possible LDH phases, depending on the orientation of the interlayer anion with respect to the brucite-like layers. The results indicated that there is a certain influence of the amine, when used as a precipitating agent, and as a consequence of the degree of substitution, on the crystallinity and particle size of the final solid obtained. The LDHs obtained using TEA exhibited higher crystallinity, which was improved after a long hydrothermal treatment by conventional heating. Regarding the shape of the particles, the formation of aggregates in the former solid was detected, which could be easily disintegrated using ultrasound treatments, producing solid powder with high crystallinity and small particle size, with homogeneous size distribution.

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Section: Powder X-ray Diffraction (Pxrd)mentioning

confidence: 94%