Development of new homogeneous photo-Fenton catalytic systems using oxalic acid and ferric ions in very low concentrations

Quoc Viet Bui, Thuy Vy Phan, Tien Khoa Le*

Vietnam National University, Ho Chi Minh city

Received 2 June 2020; accepted 3 September 2020

 

Abstract:

In this work, we proposed to combine oxalic acid and ferric ions in very low concentrations to create new, economic, and effective homogeneous photo-Fenton catalytic systems for the degradation of methylene blue. The effects of ferric concentration, H₂C₂O₄ concentration, pH, and tert-butanol on the catalytic activity were also investigated. According to the experimental results, Fe³⁺ ions exhibited impressive catalytic performances in the presence of H₂C₂O₄ at concentrations below type B (5.0 mg.L^–1) from the Vietnam National Technical Regulation on Industrial Wastewater. Specifically, a ferric concentration of 3.0 mg.L^–1, H₂C₂O₄ concentration of 10^–3 mol.L^–1, and pH value of 3 were found to be the best conditions for MB degradation under UVA light. Furthermore, owing to a very low concentration of ferric ions, iron sludge formation can be avoided after wastewater treatment, which makes the photo-Fenton process suitable for practical applications.

Keywords: ferric ions, homogeneous photo-Fenton activity, methylene blue, oxalic acid, very low concentration.

Classification number: 2.2