Heterogeneous electro-Fenton treatment of coking wastewater using Fe/AC/Ni cathode: optimization of electrode and reactor organic loading

ABSTRACT

A self-developed iron-loaded activated carbon-based nickel foam electrode (Fe/AC/Ni cathode) was used to construct electro-Fenton reaction system to treat coking wastewater. To meet the gap between laboratory beaker experiments and field trials for practical applications, we proposed and validated a method for obtaining organic loads, the essential parameters used in the design of electrochemical systems for wastewater treatment. The three influencing factors most relevant to organic loading, the effective surface area of cathode, chemical oxygen demand (COD) concentration of influent, and treatment time, were selected and investigated for their effects on the COD removal rate of coking wastewater by single-factor experiments and further optimized by response surface method. The appropriate electrode area load (L_a) and reactor volume load (L_v) were calculated by their corresponding intrinsic relationships with the three factors. The optimum application conditions were effective surface area of cathode 28.5 cm², COD concentration of influent 1.76 kg·m⁻³, and treatment time 160.43 min. Under these conditions, the maximum COD removal rate was 98.51%. The L_a and L_v were 8.905 mgCOD·cm⁻²·h⁻¹ and 0.634 kgCOD·m⁻³·h⁻¹, respectively. The characterization experiment results showed that the Fe/AC/Ni cathode had a significant effect on the treatment of refractory organic contaminants in coking wastewater.

GRAPHICAL ABSTRACT

KEYWORDS:

• Coking wastewater
• electro-Fenton method
• Fe/AC/Ni cathode
• response surface method
• organic load

Acknowledgments

This work was kindly funded by the University of Science and Technology Liaoning under Grant (No. 2019FW03).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

This work was supported by University of Science and Technology Liaoning: [Grant Number 2019FW03].