Detoxification of toxic dyes using biosynthesized iron nanoparticles by photo-Fenton processes

Environmental contamination resulting from dyes has become a serious concern for today's world. The textile effluents are highly colored, and the disposal of these in water bodies causes severe damage to the environment by reducing the solar light penetration which may affect the photosynthetic activity and the aquatic life in water. Further, the high water solubility of dyes also leads to surface and ground water contamination. Thus, in this study, we attempt to develop a cost-effective and eco-friendly method for removal of toxic dyes from aqueous using biosynthesized iron nanoparticles (INPs). Various complimentary instruments such as a thermogravimetric analysis, scanning electron microscopy/energy dispersive X-ray spectrometer, and X-ray diffraction were employed for identification and characterization of INPs. The biosynthesized INPs were applied as a Fenton-like catalyst for decolorization of toxic dyes solution like methylene blue, methyl orange, allura red, brilliant blue, and green S using hydrogen peroxide under solar radiation. The decolorization of the toxic dyes solution using INPs was monitored by UV-visible spectrophotometer, and the data obtained were utilized to evaluate the kinetic rate of the reactions. The kinetic data suggest that the decolorization of all studied toxic dyes solution follows first-order rate with rate constant values in the range of 13.1 x 10(-3)-17.7 x 10(-3) min(-1). Therefore, such a clean method employing non-toxic plant extract in INP synthesis and the application of INPs as a Fenton-like catalyst in toxic dyes decolorization can be considered as an alternative technique to the expensive and toxic chemical methods.