A novel synthesis of sulfurized magnetic biochar for aqueous Hg(II) capture as a potential method for environmental remediation in water

Che-Jung Hsu; Yung-Hua Cheng; Ying-Pin Huang; John D Atkinson; Hsing-Cheng Hsi

doi:10.1016/j.scitotenv.2021.147240

A novel synthesis of sulfurized magnetic biochar for aqueous Hg(II) capture as a potential method for environmental remediation in water

Sci Total Environ. 2021 Aug 25:784:147240. doi: 10.1016/j.scitotenv.2021.147240. Epub 2021 Apr 22.

Authors

Che-Jung Hsu¹, Yung-Hua Cheng¹, Ying-Pin Huang², John D Atkinson³, Hsing-Cheng Hsi⁴

Affiliations

¹ Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 10617, Taiwan.
² South Region Services Department, Commercialization and Industry Service Center, Industrial Technology Research Institute, Tainan 73445, Taiwan.
³ Department of Civil, Structural and Environmental Engineering, The State University of New York at Buffalo, Buffalo, NY 14260, United States. Electronic address: atkjdw@buffalo.edu.
⁴ Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 10617, Taiwan. Electronic address: hchsi@ntu.edu.tw.

PMID: 34088046
DOI: 10.1016/j.scitotenv.2021.147240

Abstract

Due to public health threats resulting from mercury (Hg) and its distribution in the food chain, global restrictions have been placed on Hg use and emissions. Biochar is a porous, carbonaceous adsorbent typically derived from waste biomass or organic matter, making it an eco-friendly material for aqueous mercury (Hg(II)) control. Functionalization of biochar can improve performance in pollution control applications. In this work, carbonization, magnetization, and sulfurization of biochar were combined into a single heating step to prepare sulfurized magnetic biochar (SMBC) for Hg(II) removal from water. Results indicate that SMBC prepared at 600 °C adsorbed 8.93 mg/g Hg(II), more than materials prepared at 400, 500, 700, 800, and 900 °C. Additionally, Hg(II) adsorption onto SMBC was 53.0% and 11.5% greater than onto magnetic biochar (MBC) and biochar (BC), respectively. Hg(II) adsorption is shown to be favorable in acidic conditions (pH 3.5-5), thermodynamically spontaneous, and endothermic. Adsorption results fit the pseudo-second-order (R² = 0.990 and the sum of squared error (SSE) = 5.382) and external mass transfer (R² = 0.971 and SSE = 9.422) models. The partitioning coefficients were 4.964 mg/g/μM in freshwater, 0.176 mg/g/μM in estuary water, and 0.275 mg/g/μM in seawater, highlighting the importance of salinity in environmental remediation applications. In summary, SMBC can be readily prepared with minimal processing steps. The product is a robust adsorbent for Hg(II), and it can potentially be applied to remediate contaminated water/sediment/soil in the future.

Keywords: Adsorption; Biochar; Magnetic adsorbent; Mercury.