Highly efficient photodegradation of RhB–MO mixture dye wastewater by Ag3PO4 dodecahedrons under acidic condition

•A low pH value favors for the formation of more ·OH free radicals.•A high degradation efficiency of dye can be achieved under acidic condition.•In the RhB–MO mixture dye solution, the degradation MO is faster than that of RhB.

We report the photodegradation of rhodamine B (RhB), methyl orange (MO) and their mixture solutions at different pH values by the Ag3PO4 dodecahedrons, which are synthesized by a simple precipitation method at room temperature. The samples are characterized by X-ray diffraction spectra (XRD), scanning electron microscope (SEM) and UV–vis diffuse-reflection spectra (UV-DRS). The contrast experiments, in which dimethyl sulfoxide (DMSO) is added as the scavenger of ·OH, confirm that the addition of acid favors the formation of more ·OH free radicals. As a result, the higher degradation efficiency can be achieved under acidic condition than under alkaline and neutral conditions for RhB, MO and their mixture dyes. Furthermore, the Ag3PO4 dodecahedrons also show a high visible-light degradation activity for the RhB–MO mixture dye solution, in which the degradation efficiency of MO is significantly superior to that of RhB. This work could be expected to make a big step toward the practical application of photocatalysis technology.

Graphical abstractA higher degradation activity of the RhB–MO mixture dye wastewater can be achieved under acidic condition by Ag3PO4.Figure optionsDownload full-size imageDownload high-quality image (100 K)Download as PowerPoint slide