Fluorescence modulation and photodegradation characteristics of safranin O dye in the presence of ZnS nanoparticles

ZnS nanoparticles were synthesized using a chemical precipitation method and were characterized with FTIR, transmission electron microscope (TEM), X-ray diffraction analysis (XRD) and UV–vis absorption. XRD analysis shows that the diameter of the particles is 1.6 nm. The interaction between ZnS nanoparticles and safranin O (SO) dye was studied with UV–vis absorption as well as fluorescence emission and excitation spectra. The results show fluorescence enhancement from dye molecules with nanoparticles upon excitation at 325 nm. In contrast, the fluorescence of the dye monitored at 520 nm is quenched by ZnS nanoparticles. ZnS nanoparticles were used as a photocatalyst in order to degrade SO dye. A maximum degradation efficiency of 51% of the dye has been achieved in the presence of ZnS as a nanophotocatalyst at pH 7. Photodegradation of the dye follows second-order kinetics.