Study of photocatalytic activity of ZnS quantum dots as efficient nanoparticles for removal of methyl violet: effect of ferric ion doping.

Zinc sulfide quantum dots (QDs), as pure and doped with Fe(3+), were prepared for photodecolorization of methyl violet (MV), as a model dye, under UV light irradiation. The syntheses of QDs were carried out using a simple chemical co-precipitation method. The prepared samples were characterized by various techniques including X-ray diffraction, transmission electron microscopy, UV-Vis spectrophotometry and flame atomic absorption spectroscopy. The influences of operational parameters on the decolorization of MV such as dopant content, pH, dosage of nanophotocatalyst, UV irradiation time and initial dye concentration were studied. The results showed that the QDs presented high efficiency for MV decolorization, and doping of ZnS QDs with Fe(3+) enhanced the efficiency and rate of dye removal. Finally, the reproducibility and kinetic model of the dye degradation were discussed.