A novel synthesis of sulfurized magnetic biochar for aqueous Hg(II) capture as a potential method for environmental remediation in water
Journal
Science of the Total Environment
Journal Volume
784
Date Issued
2021
Author(s)
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. © 2021 Elsevier B.V.
Subjects
Adsorption; Biochar; Magnetic adsorbent; Mercury
Other Subjects
Adsorption; Carbonaceous adsorbents; Carbonization; Chemical contamination; Health risks; Mass transfer; Mercury (metal); Mercury compounds; Pollution control; Water pollution; Bio chars; Environmental remediation; Foodchain; Magnetic adsorbents; Mercurie
Type
journal article