Degradation of glyphosate herbicide by an electro-Fenton process using carbon felt cathode

ABSTRACT

An electro-Fenton system, which consists of a Pt gauze anode and a commercial carbon felt cathode, is commonly employed to generate in situ hydrogen peroxide, hydroxyl radical and regenerate ferrous catalyst for glyphosate degradation (a widely used herbicide in Vietnam) in aqueous solution. The absorbance measurements used to determine the glyphosate concentration during the electrolysis proved that glyphosate was degraded by pseudo-first-order kinetic. The influence of pH, current density, catalyst concentration and initial content of the glyphosate on mineralisation efficiency were studied by monitoring the total organic carbon (TOC) and hydrogen peroxide concentration during electrolysis. The results show that the maximal removal percentage of glyphosate was 91.91% with applied current density of 10 mA cm⁻², pH 3, 0.1 mM Fe²⁺, 0.05 M Na₂SO₄, and 0.1 mM glyphosate in 40 min. The degrading rate constant of glyphosate degradation was calculated to be k_app = 0.063 min⁻¹. In this 91.91% removal, 81.65% of glyphosate was mineralised and the remainder consists of intermediates produced during the electro-Fenton process.

GRAPHICAL ABSTRACT

KEYWORDS:

• Electro-Fenton
• hydroxyl radical
• glyphosate
• felt carbon
• herbicide removal

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported financially by the project of the Vietnam Academy of Science and Technology (VAST) [VAST07.03/15-16 project].