ZnFe-layered double hydroxide nanostructures prepared from natural iron ore precursors with the hydrothermal method and the photocatalytic degradation of Rhodamine B

This paper investigates the use of low-cost natural iron ore in the preparation of binary metal lay-ered double hydroxide (ZnFe-LDH) nanostructures via a hydrothermal process. In particular, the photocatalytic degradation of Rhodamine B under UV light irradiation is utilized. Natural iron ore is used to prepare the iron(III) precursors (Fe3+) necessary for building the ZnFe-LDH nanostruc-tures. Preparation is done at 80 & DEG;C-100 & DEG;C for 36 h and does not involve a calcination process. The physicochemical characterizations of the prepared samples are carried out via X-ray diffraction, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy, and photoluminescence. After confirming the existence of the ZnFe-LDH nanostructures via their functional groups and elemental compositions, it is noted that they have high crystallinity and small crystal sizes. The morphologies of the ZnFe-LDH nanostructures are irregular, with small particles agglomerated on their surfaces. While good optical properties are enhanced as the preparation temperature is increased, the results show that crystallinity, crystal size, particle uniformity, and narrow bandgap energy play important roles in the subsequent photocatalytic reactions. The optimum conditions for the photodegradation of 10 ppm Rhodamine B solution are reached with 1.00 g/L of ZnFe-LDH nanostructures prepared using the hydrothermal method at 100 & DEG;C for 36 h. At maximum efficiency, the photodegradation process can be completed at a rate constant of 0.2060 min-1 in 20 min and an EEO of 44.74 kWh/ m3 with the addition of a 0.9% v/v H2O2 electron acceptor. Photocatalyst efficiency decreases by just 12.5% across five test cycles.