Biochar-supported sulfurized nanoscale zero-valent iron facilitates extensive dechlorination and rapid removal of 2,4,6-trichlorophenol in aqueous solution

Ying Wang; Wei Jiang; Yanqiang Tang; Zheming Liu; Qingdong Qin; Yan Xu

doi:10.1016/j.chemosphere.2023.138835

Biochar-supported sulfurized nanoscale zero-valent iron facilitates extensive dechlorination and rapid removal of 2,4,6-trichlorophenol in aqueous solution

Chemosphere. 2023 Aug:332:138835. doi: 10.1016/j.chemosphere.2023.138835. Epub 2023 May 2.

Authors

Ying Wang¹, Wei Jiang², Yanqiang Tang³, Zheming Liu⁴, Qingdong Qin⁵, Yan Xu⁶

Affiliations

¹ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: ying_wangjiayou@163.com.
² Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: jiangwei_cqu@sina.com.
³ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: tyq828@163.com.
⁴ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: seulzm@163.com.
⁵ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: qinqingdong@seu.edu.cn.
⁶ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: xuxucalmm@seu.edu.cn.

PMID: 37142104
DOI: 10.1016/j.chemosphere.2023.138835

Abstract

Nanoscale zero-valent iron (NZVI) has been widely used in rapid remediation of contaminants. However, several obstacles such as aggregation and surface passivation hampered NZVI from further application. In this study, sulfurized nanoscale-zero valent iron supported by biochar (BC-SNZVI) was successfully synthesized and utilized for highly efficient 2,4,6-trichlorophenol (2,4,6-TCP) dechlorination in aqueous solution. SEM-EDS analysis revealed the even distribution of SNZVI on the surface of BC. FTIR, XRD, XPS and N₂ Brunauer-Emmett-Teller (BET) adsorption analyses were carried out to characterize the materials. Results showed that BC-SNZVI with S/Fe molar ratio of 0.088, Na₂S₂O₃ as sulfurization agent, and pre-sulfurization as the sulfurization strategy exhibited the superior performance for 2,4,6-TCP removal. The overall removal of 2,4,6-TCP was well described with the pseudo-first-order kinetics (R² > 0.9), and the observed kinetics constant K_obs was 0.083 min^-1 with BC-SNZVI, which was one order of magnitude higher than that of BC-NZVI (0.0092 min^-1) and SNZVI (0.0042 min^-1), and two orders of magnitude higher than that of NZVI (0.00092 min^-1). Moreover, the removal efficiency of 2,4,6-TCP reached 99.5% by BC-SNZVI with dosage of 0.5 g L^-1, initial 2,4,6-TCP concentration of 30 mg L^-1 and initial solution pH of 3.0 within 180 min. The removal of 2,4,6-TCP by BC-SNZVI was acid-promoted and the removal efficiencies of 2,4,6-TCP decreased with the increase of initial 2,4,6-TCP concentrations. Furthermore, more extensive dechlorination of 2,4,6-TCP was achieved with BC-SNZVI and complete dechlorination product phenol became predominant. The facilitation of sulfur for Fe⁰ utilization and electron distribution in the presence of biochar remarkably enhanced the dechlorination performance of BC-SNZVI for 2,4,6-TCP. These findings provide insights into BC-SNZVI as an alternative engineering carbon based NZVI material for treating chlorinated phenols.

Keywords: 2,4,6–trichlorophenol; Biochar supported sulfurized nanoscale zero–valent iron; Dechlorination.

MeSH terms

Adsorption
Charcoal / chemistry
Iron* / chemistry
Water
Water Pollutants, Chemical* / analysis

Substances

Iron
biochar
2,4,6-trichlorophenol
Water Pollutants, Chemical
Charcoal
Water