Background: Wastewater with dyes pollutes the environment and causes serious risk to
human health and aquatic biota. Gentian violet (GV) belongs to typical triphenylmethane dyes and is
difficult to be degraded. Calcium bismuthate nanoflakes possess good photocatalytic activity toward
GV under solar light irradiation.
Objective: The aim of the study was to prepare calcium bismuthate nanoflakes by the hydrothermal
method and research on the solar light photocatalytic performance of the calcium bismuthate
nanoflakes for GV degradation.
Methods: Calcium bismuthate nanoflakes were synthesized via a facile hydrothermal route assisted
by cetyltrimethylammonium bromide (CTAB) based on the reaction of sodium bismuthate and calcium
chloride. The calcium bismuthate products were analyzed by X-ray diffraction (XRD), scanning
electron microscopy (SEM), transmission electron microscopy and solid UV-vis diffuse reflectance
Results: The calcium bismuthate nanoflakes possess single crystalline monoclinic CaBi2O4 phase.
The size of the whole nanoflakes is about 10 μm and the thickness of the nanoflakes is about 40 nm.
The morphology, size and phase of the products are closely relative to CTAB concentration, reaction
temperature and reaction time. The bandgap of the calcium bismuthate nanoflakes is 2.21 eV. The
photocatalytic activity of the calcium bismuthate nanoflakes is high enough to completely degrade
GV under solar light irradiation for 6 h.
Conclusion: The photocatalytic performance for the removal of GV is dependent on the irradiation
time, dosage of the calcium bismuthate nanoflakes and initial GV concentration. The calcium bismuthate
nanoflakes exhibit great promising activity for the removal of organic pollutants.