PHOTO-CATALYTIC DEGRADATION OF DYE BY ZINC OXIDE BASED CATALYST

Abstract

In the present study, photocatalytic oxidation of dye bearing wastewater has been done using iron doped zinc oxide photocatalyst. Various iron doped zinc oxide (Fe/ZnO) photocatalysts were synthesized by solution combustion synthesis method and its structural, morphological and optical properties were studied using N2 adsorption-desorption, fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), thermogravimetric analysis (TGA) , field emission scanning electron microscope (FE-SEM), transition electron microscope (TEM), energy dispersive analysis of X-rays spectroscopy (EDAX), and UV-visible diffuse reflectance spectra (UV-DRS). Synthesized catalyst activity was monitored by optimizing reaction parameters of photocatalytic oxidation process. XRD patterns of all samples showed a hexagonal wurtzite structure. The diffuse reflectance spectra of the prepared samples have shown the maximum absorption of light in the UV region stating that these catalysts can be used as photocatalysts.Using tauc plots band gap energies of all samples were determined and have values in the range of 3.14-3.38 eV. The BET surface area analysis of photocatalyst showed a good value of surface area to treat the dye solution. The presence of pronounced hysteresis in N2 adsorption-desorption isotherm curves indicated the three dimensional network arrangement of the pores in the Fe/ZnO sample prepared using solution combustion synthesis method. The photodegradation ability of the catalysts were tested for the photodegradation of an azo dye named as acid red 1 dye. . Effect of various reaction parameters such as amount of iron doped, calcination temperature, calcination time, pH of dye solution, catalyst dose, hydrogen peroxide dose, reaction temperature and initial concentration of dye solution were optimized by taking color removal and degradation of dye as response. At optimum conditions, more that 71% color removal and 94% dye degradation was observed for acid red 1 dye solution having initial concentration of 50 mg/l and initial color 2730 Pt:Co units.