Degradation of aqueous methylparaben by non-thermal plasma combined with ZnFe2O4-rGO nanocomposites: Performance, multi-catalytic mechanism, influencing factors and degradation pathways

Jingwei Feng; Peng Nian; Lu Peng; Aiyong Zhang; Yabing Sun

doi:10.1016/j.chemosphere.2021.129575

Degradation of aqueous methylparaben by non-thermal plasma combined with ZnFe₂O₄-rGO nanocomposites: Performance, multi-catalytic mechanism, influencing factors and degradation pathways

Chemosphere. 2021 May:271:129575. doi: 10.1016/j.chemosphere.2021.129575. Epub 2021 Jan 9.

Authors

Jingwei Feng¹, Peng Nian², Lu Peng², Aiyong Zhang³, Yabing Sun⁴

Affiliations

¹ Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China; State Key Laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210046, China; Anhui Province Key Laboratory of Industrial Wastewater and Environmental Treatment, Hefei, 230024, China. Electronic address: jingweifeng@hfut.edu.cn.
² Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China; East China Engineering Science and Technology Co., Ltd., Hefei, 230024, China.
³ Anhui Provincial Engineering Laboratory for Rural Water Environment and Resources, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China. Electronic address: ayzhang@hfut.edu.cn.
⁴ State Key Laboratory of Pollution Control & Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210046, China.

PMID: 33460902
DOI: 10.1016/j.chemosphere.2021.129575

Abstract

Non-thermal plasma (NTP) combined with zinc ferrite-reduced graphene oxide (ZnFe₂O₄-rGO) nanocomposites were used for the degradation of aqueous methylparaben (MeP). ZnFe₂O₄-rGO nanocomposites were prepared using the hydrothermal method, with the structure and photoelectric properties of nanocomposites then characterized. The effects of discharge power, initial MeP concentration, initial pH, and air flow rate on MeP degradation efficiency were investigated, and the multi-catalytic mechanism and MeP degradation pathways were established. Results showed that ZnFe₂O₄-rGO nanocomposites with a 10%:90% mass ratio of GO:ZnFe₂O₄ had an optimal catalytic effect. The MeP degradation efficiency of NTP combined with ZnFe₂O₄-rGO (10 wt%), was approximately 25% higher than that of NTP alone. Conditions favorable for MeP degradation included higher discharge power, lower MeP concentration, neutral pH value, and higher air flow rate. The degradation of MeP by NTP combined with ZnFe₂O₄-rGO nanocomposites followed pseudo-first-order kinetics. O₂^•-, •OH, H₂O_2, and O₃ were found to play important roles in the MeP degradation, as part of the multi-catalytic mechanism of NTP combined with ZnFe₂O₄-rGO nanocomposites. MeP degradation pathways were proposed based on the degradation intermediates detected by gas chromatography mass spectrometry, including demethylation, hydroxylation, carboxylation, ring-opening, and mineralization reactions. The prepared ZnFe₂O₄-rGO nanocomposites provide an approach for improved contaminant degradation efficiency, with reduced energy consumption in the NTP process.

Keywords: Degradation pathway; Methylparaben; Multi-catalytic mechanism; Non-thermal plasma; ZnFe(2)O(4)-rGO.

MeSH terms

Graphite*
Nanocomposites*
Parabens
Plasma Gases*

Substances

Parabens
Plasma Gases
graphene oxide
Graphite
methylparaben