Electrochemical incineration of glyphosate wastewater using three-dimensional electrode

ABSTRACT

Anodic oxidation of recalcitrant organic compounds is still challenging concerning to the anode material and mass transport limitations imposed by the low concentration. In this work, we studied the degradation of a real wastewater containing glyphosate using an electrode of PbO₂ electrodeposited on a three-dimensional matrix of reticulated vitreous carbon (RVC). The high mass transfer rate provided by the RVC/PbO₂ anode is demonstrated. A Box–Behnken factorial design was used for a systematic analysis of the effects of current density, flow rate and temperature on the degradation and mineralisation kinetics, current efficiency and specific energy consumption. The optimised degradation performance was achieved applying 30 mA cm⁻², 3000 mL min⁻¹ and 50°C. As the flow rate increases from 150 to 1500 mL min⁻¹, the current efficiency increases from 18% to 65% and the energy consumption dropped from 72 to 33 kWh kg⁻¹ due to the mass transfer enhancement promoted by the porous matrix. The efficacy of the electrochemical process for the treatment of real effluents using the three-dimensional PbO₂ has been demonstrated.

GRAPHICAL ABSTRACT

KEYWORDS:

• Anodic oxidation
• glyphosate
• wastewater treatment
• mass transfer
• Box–Behnken design

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by São Paulo Research Foundation (FAPESP) [grant number 2012/04168-0]. The authors also thank the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) and the National Council for Scientific and Technological development (CNPq) for the fellowships.