Issue 2, 2022

Graphitic carbon nitride and carbon nanotubes modified active carbon fiber cathode with enhanced H2O2 production and recycle of Fe3+/Fe2+ for electro-Fenton treatment of landfill leachate concentrate

Abstract

The electro-Fenton (EF) technique has attracted great interest in the treatment of landfill leachate concentrate (LLC). Active carbon fiber (ACF) was modified with graphitic carbon nitride (g-C3N4), carbon nanotubes (CNTs) and polytetrafluoroethylene (PTFE) through a wet ultrasonic impregnation–calcination process, which enhanced the production of H2O2 and regeneration of active Fe(II) in an EF system. The experiments on physicochemical characterization demonstrated that the modified ACF was provided with more active sites and the hydrophobicity of the electrode was improved, facilitating the O2 mass transfer. Through comparison with pristine ACF, g-C3N4/ACF and CNTs/ACF, electrochemical experiments showed that g-C3N4/CNTs/ACF exhibited the best performance on the electrocatalytic activity of the oxygen reduction reaction (ORR) and electron transfer efficiency attributed to the synergetic effect of g-C3N4 and CNTs. Fulvic acids (FA) were used to simulate LLC to investigate the effect of operational parameters on EF performance. Under optimal conditions, H2O2 production of g-C3N4/CNTs/ACF reached 132 mg L−1 with an H2O2 generation rate of 3.96 mg h−1 cm−2 and 86% FA was removed with a kinetic rate of 0.046 within 2 h. Simultaneously, the concentration of dissolved Fe2+ in the system increased from 2.5 mg L−1 to 6.4 mg L−1 after modification, thus continuously reacting with H2O2 to produce more ˙OH. Remarkably, an excellent EF performance was achieved with g-C3N4/CNTs/ACF in the treatment of LLC, where 74.7% of TOC was removed with an economical energy consumption of 5.76 kW h kgTOC−1 and biodegradability was improved significantly, as concluded from the results of UV-vis and a 3D excitation–emission matrix (EEM). After 10 cycles, H2O2 production could still reach 120 mg L−1 and the mineralization rate remained at 66%. This work develops an efficient, cost-effective, and durable EF cathode for the treatment of LLC.

Graphical abstract: Graphitic carbon nitride and carbon nanotubes modified active carbon fiber cathode with enhanced H2O2 production and recycle of Fe3+/Fe2+ for electro-Fenton treatment of landfill leachate concentrate

Supplementary files

Article information

Article type
Paper
Submitted
29 11月 2021
Accepted
21 12月 2021
First published
22 12月 2021

Environ. Sci.: Nano, 2022,9, 632-652

Graphitic carbon nitride and carbon nanotubes modified active carbon fiber cathode with enhanced H2O2 production and recycle of Fe3+/Fe2+ for electro-Fenton treatment of landfill leachate concentrate

M. Li, X. Qin, M. Gao, T. Li and Y. Lv, Environ. Sci.: Nano, 2022, 9, 632 DOI: 10.1039/D1EN01095F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements