Photocatalytic degradation of caffeine by ZnO-ZnAl2O4 nanoparticles derived from LDH structure

• Published in: Journal of environmental chemical engineering Vol. 5; no. 4; pp. 3719 - 3726
• Main Authors: Elhalil, A., Elmoubarki, R., Machrouhi, A., Sadiq, M., Abdennouri, M., Qourzal, S., Barka, N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2017
• Subjects: Caffeine; Layered double hydroxides; Pharmaceutical pollutants; Photocatalytic activity; Reconstruction; Wastewater treatment; Reconstruction; Photocatalytic activity; Wastewater treatment; Pharmaceutical pollutants; Layered double hydroxides; Caffeine
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2017.07.037

•Preparation of ZnO-ZnAl2O4 mixed phases by calcination of Zn-Al-CO3 LDH precursors.•Remarkable photocatalytic degradation performance of caffeine in aqueous solution.•Crystallinity, adsorption and dispersion of active ZnO were the important factors.
In this research, ZnO-ZnAl2O4 mixed phases were prepared by calcination of Zn-Al-CO3 layered double hydroxides (LDH) precursors. Firstly, a series of Zn-Al-CO3 LDH were synthesized at different Zn/Al molar ratios (r=1, 3 and 5) and then calcined at different temperatures (300, 400, 500, 600, 800 and 1000°C) for 6h. The materials were characterized by XRD, FTIR, TGA/DTA, ICP-AES and TEM. The photocatalytic activity of the samples was evaluated for the degradation of caffeine as a model pharmaceutical pollutant in aqueous solution under UV irradiation. The effect of the Zn/Al molar ratio, calcination temperature and initial pH of aqueous solution was investigated. The experimental results show that the sample obtained from the molar ratio of 3 and calcined at 500°C with a large capacity of adsorption obtained by reconstruction process was photocatalytically much higher than standard Degussa P-25 titanium dioxide.