Low-Cost Photo-Fenton-Like Process for the Removal of Synthetic Dye in Aqueous Solution at Circumneutral pH

Abstract

Fenton-like processes have been widely studied in recent years and are considered promising for organic wastewater treatment. Enhancement of wastewater treatment performance involves the development of economical and environmental aspects of the process. The present work aims to investigate the degradation and mineralization of an organic model compound, namely patent blue V (PBV) in aqueous solution. The process adopted uses the Fenton-like mode enhanced by UV light, using a low amount of reagent at natural pH, which was close to neutral. Some key parameters including UV light, H2O2 dosage, catalyst amount and initial dye concentration in the homogeneous Fenton-like processes were discussed. The complete degradation of 10 mg/L of PBV was obtained in 1 h with low reagent concentrations (0.98 mg/L and 39.1 mg/L of Fe3+ and H2O2, respectively) at natural pH (6.4). The mineralization was justified through the determination of sulfates, nitrates and calcium formed during oxidation. The reaction obeys the pseudo-first-order and kinetic constants, namely the apparent rate constant, the half-life time and the catalytic efficiency, strongly depend on the catalyst concentration. The reutilization of the generated sludge in the photo-Fenton-like process was discussed. However, in spite of the decrease in the degradation efficiency, the possibility of recycling the catalyst Fe3+ as sludge Fe(OH)3 makes the process photo-Fenton-like, cheaper and environment friendly.