Spectroscopic characterization of soil dissolved organic matter during dielectric barrier discharge (DBD) plasma treatment: Effects of discharge power, atmosphere and soil moisture content

Yanan Liu; Siyu Deng; Lulu Chen; Ai Zhang; Supakij Suttiruengwong; Zhuyu Sun

doi:10.1016/j.chemosphere.2022.134145

Spectroscopic characterization of soil dissolved organic matter during dielectric barrier discharge (DBD) plasma treatment: Effects of discharge power, atmosphere and soil moisture content

Chemosphere. 2022 Jun:297:134145. doi: 10.1016/j.chemosphere.2022.134145. Epub 2022 Feb 28.

Authors

Yanan Liu¹, Siyu Deng², Lulu Chen², Ai Zhang², Supakij Suttiruengwong³, Zhuyu Sun⁴

Affiliations

¹ College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
² College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
³ Department of Materials Science and Engineering, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, 73000, Thailand.
⁴ College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China. Electronic address: sunzhuyu@dhu.edu.cn.

PMID: 35240150
DOI: 10.1016/j.chemosphere.2022.134145

Abstract

Non-thermal plasma (NTP) technology is an emerging advanced oxidation process, which has shown excellent performances in soil organic pollution remediation. Dissolved organic matter (DOM) is one of the most important components in soil, however, investigations on the structural and compositional changes of DOM during NTP process are lacking. Therefore, in the present study, we systematically investigated the soil DOM changes under different discharge voltages, atmospheres or soils with different moisture contents. The results indicated that after NTP treatment, substantial soil organic matters were released and dissolved in water. For instance, the DOC value of DOM increased dramatically from 21.1 to 197.3 mg L^-1 after being discharged for 120 min under the discharge voltage of 80 V. The UV-Vis characterization results indicated the significant increase of hydrophilicity, and decreases of aromaticity and molecular weight for soil DOM during the initial discharge period. However, long time discharge resulted in slight recovery of aromaticity and hydrophobicity, possibly due to the dehydration and re-condensation of small molecules. EEM-FRI results indicated that the total fluorescence intensity of DOM decreased obviously, indicating the destruction of fluorescent dissolved organic matter (FDOM). While the proportions of humic-like and microbial byproduct-like substances increased, indicating that those substances were more recalcitrant under NTP treatment compared with fulvic acid-like and aromatic protein-like substances. Four fluorescence components were identified by PARAFAC, and microbial and terrestrial humic-like substances were more difficult to degrade compared to other humic-like substances and fulvic acid-like substances. Additionally, discharge voltage and atmosphere had great influences on DOM changes, while the impact of soil moisture content was not significant. Overall, this study provided insights into the DOM changes during NTP process, which is valuable for more comprehensive evaluation of the NTP technique application in practical soil remediation.

Keywords: Compositional changes; Dielectric barrier discharge (DBD); Dissolved organic matter (DOM); Fluorescence regional integration (FRI); Parallel factor (PARAFAC); Spectroscopic characterization.

MeSH terms

Atmosphere
Dissolved Organic Matter*
Humic Substances / analysis
Soil* / chemistry
Spectrometry, Fluorescence

Substances

Dissolved Organic Matter
Humic Substances
Soil