Mitigation of arsenic release by calcium peroxide (CaO2) and rice straw biochar in paddy soil

Hye-Bin Kim; Jong-Gook Kim; Daniel S Alessi; Kitae Baek

doi:10.1016/j.chemosphere.2023.138321

Mitigation of arsenic release by calcium peroxide (CaO₂) and rice straw biochar in paddy soil

Chemosphere. 2023 May:324:138321. doi: 10.1016/j.chemosphere.2023.138321. Epub 2023 Mar 4.

Authors

Hye-Bin Kim¹, Jong-Gook Kim¹, Daniel S Alessi², Kitae Baek³

Affiliations

¹ Department of Environment and Energy (BK21 FOUR), Jeonbuk National University, Jeonju, Jeollabukdo, 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, Jeonju, Jeollabukdo, 54896, Republic of Korea.
² Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada.
³ Department of Environment and Energy (BK21 FOUR), Jeonbuk National University, Jeonju, Jeollabukdo, 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, Jeonju, Jeollabukdo, 54896, Republic of Korea; Department of Civil, Environmental, Resources and Energy Engineering, Jeonbuk National University, Jeonju, Jeollabukdo, 54896, Republic of Korea. Electronic address: kbaek@jbnu.ac.kr.

PMID: 36878361
DOI: 10.1016/j.chemosphere.2023.138321

Abstract

Biochar has a great potential in the stabilization of soil heavy metals; however, the application can actually enhance the mobility of Arsenic (As) in soil. Here, a biochar-coupled calcium peroxide system was proposed to control the increase in As mobility caused by biochar amendment in paddy soil environment. The capability of rice straw biochar pyrolyzed at 500 °C (RB) and CaO₂ to control As mobility was evaluated by incubation for 91 days. CaO₂ encapsulation was performed for pH control of CaO₂, and As mobility was evaluated using a mixture of RB + CaO₂ powder (CaO₂-p), and RB + CaO₂ bead (CaO₂-b), respectively. The control soil solely and RB alone were included for comparison. The combination of RB with CaO₂ exhibited remarkable performance in controlling As mobility in soil, and As mobility decreased by 40.2% (RB + CaO₂-p) and 58.9% (RB + CaO₂-b) compared to RB alone. The result was due to high dissolved oxygen (6 mg L^-1 in RB + CaO₂-p and RB + CaO₂-b) and calcium concentrations (296.3 mg L^-1 in RB + CaO₂-b); oxygen (O₂) and Ca²⁺ derived from CaO₂ is able to prevent the reductive dissolution and chelate-promoted dissolution of As bound to iron (Fe) oxide by biochar. This study revealed that the simultaneous application of CaO₂ and biochar could be a promising way to mitigate the environmental risk of As.

Keywords: Arsenic; Biochar; Calcium peroxide (CaO(2)); Mobility.

MeSH terms

Arsenic* / analysis
Charcoal / metabolism
Oryza* / metabolism
Soil
Soil Pollutants* / analysis

Substances

Arsenic
biochar
calcium peroxide
Soil
Charcoal
Soil Pollutants