Thin films containing oxalate-capped iron oxide nanomaterials deposited on glass substrate for fast Fenton degradation of some micropollutants

Abstract

The main goal of the study was to evaluate the catalytic activity of two hybrid nanocatalysts consisting in Fe₃O₄ nanoparticles modified with either chitosan (CS) or polyethylene glycol (PEG)/ferrous oxalate (FO), and further deposited on solid substrate as thin films. X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) were employed for the structural and morphological characterizations of the heterogeneous catalysts. The degradation kinetic studies of two reactive azo dye (Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84)) as well as Bisphenol A (BPA) solutions were carried out using Fenton-like oxidation, in the presence of different concentrations of H₂O₂, at initial near-neutral pH and room temperature. The results indicated that a low amount of catalytic material (0.15 g/L), deposited as thin film, was able to efficiently trigger dye degradation in solution in the presence of 6.5 mmol/L H₂O₂ for RB5 and of only 1.6 mmol/L H₂O₂ in the case of BPA and RY84. In the presence of complex matrices such as WWTP waters, the removal of BPA was low (only 24% for effluent samples). Our findings recommend the studied immobilized nanocatalysts as promising economical tools for the pre-treatment of wastewaters using advanced oxidation processes (AOPs).