Photodegradation of methyl orange dye by ZnO loaded onto carbon xerogels composites

The present paper studies the photocatalytic behavior of pure zinc oxide (ZnO) and ZnO loaded onto carbon xerogel as a substrate. These samples were prepared by a sol‐gel process in presence of either an ionic liquid or an alcohol such as 1‐ethyl‐3‐methylimidazolium trifluoromethylsulfonate (A) or isopropanol solvent (B) to produce ZnO‐CX‐A and ZnO‐CX‐B photocatalysts, respectively. Transmission electron microscopy and X‐ray diffraction proved that ZnO particles were prepared as nanoflakes‐like with amorphous phase. Fourier transform infrared spectroscopy showed that ZnO‐CX‐A has a variety of surface functional groups that accelerated the photocatalytic activity of composite. The photocatalytic activity of the prepared photocatalysts was evaluated using methyl orange (MO) azo dye as a model organic compound under visible light source. As a result of the photodegradation experiments, the MO dye was completely degraded by the prepared ZnO‐CX photocatalyst composites in 120 min rather than that performed using ZnO and CX photocatalysts. However, a 98% of the MO dye solution was degraded within 90 min over ZnO‐CX‐A. The separation and reusability runs of ZnO‐CX‐A photocatalyst showed that the catalyst has high photodegradation efficiencies reaching up to 90% in the fourth run and afterward decreased to 60% in the fifth reuse. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.