Ultrasound-enhanced milling in the synthesis of phase-pure, highly crystalline ZnAl-layered double hydroxide of low Zn(II) content

• Published in: Particuology 2016-08, Vol.27, p.29-33
• Main Authors: Szabados, M., Bús, Cs, Ádok-Sipiczki, M., Kónya, Z., Kukovecz, Á., Sipos, P., Pálinkó, I.
• Format: Article
• Language: English
• Subjects: Aluminum; Aluminum base alloys; Contaminants; Diffraction; Dry milling; Drying; Hydroxides; Morphology; Ultrasonic irradiation; Zinc; ZnAl-layered double hydroxide
• ISSN: 1674-2001; 2210-4291
• DOI: 10.1016/j.partic.2016.01.006

[Display omitted] •ZnAl-layered double hydroxide (LDH) was synthesised by ultrasonically enhanced milling.•Optimum synthetic conditions were identified.•Phase-pure ZnAl-LDH with high crystallinity was obtained by rinsing the product with aqueous NH3. Dry milling followed by ultrasonic irradiation in the presence of small amounts of aqueous NaOH, was used to synthesise ZnAl-layered double hydroxide (LDH). The synthetic conditions were optimised and the Zn(OH)2, ZnO, and Al(OH)3 contaminants were removed by rinsing with aqueous NH3 solution from the sample prepared in the optimum conditions. Thus, phase-pure ZnAl-layered double hydroxide was obtained with high crystallinity. All materials produced during the syntheses were characterised by X-ray diffractometry, and a rose-like morphology was observed by scanning electron microscopy in the phase-pure sample. By changing the initial Zn/Al ratio, it was revealed that an LDH with low zinc content was always formed, probably through substitution of some of the Zn2+ ions by Al3+ ions in the gibbsite lattice.