Stabilization of Metal(loid)s Using Iron Phosphate-Coated Biochar and Its Impact on Lettuce (Lactuca sativa L.) Growth in Soil

• Published in: The Korean journal of chemical engineering Vol. 42; no. 8; pp. 1705 - 1716
• Main Authors: Kim, Han Na, Cho, Dong-Wan, Yim, Gil-Jae, Park, Jin Hee
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.07.2025; 한국화학공학회
• Subjects: Antimony; Arsenic; Bioavailability; Crops; Heavy metals; Immobilization; Iron; Lead; Lettuce; Soil analysis; Soil chemistry; Soil contamination; Soil remediation; Soil stabilization; Stabilization; 화학공학
• ISSN: 0256-1115; 1975-7220
• DOI: 10.1007/s11814-025-00410-7

Soil contamination with metalloids such as arsenic (As) and antimony (Sb) and heavy metals such as lead (Pb) in agricultural area surrounding mines affects growth of crops. Because As and Sb are stabilized by iron (Fe) hydroxide and heavy metals are stabilized by phosphate, iron phosphate-coated biochar (IPCB) simultaneously stabilizes metal(loid)s and prevents detrimental effect of metal(loid)s on crops. Therefore, the objective of the study was to evaluate lettuce growth followed by metal stabilization in soil by treating metal contaminated soil with IPCB. The lettuce grown in single and mixed metal(loid)-contaminated soil treated with IPCB showed higher dry biomass, chlorophyll content measured by soil plant analysis development (SPAD) meter, and Fv/Fm values than without IPCB indicating that IPCB mitigated toxic effect of metal(loid)s. The IPCB decreased bioavailable As, Sb, and Pb by 40.8 ± 3.0%, 23.5 ± 0.5%, and 99.0 ± 0.4% in single contaminated soil, which further decreased in mixed metal(loid)-contaminated soil. Arsenic, Sb, and Pb uptake of lettuce shoots decreased by 21.6 ± 9.4%, 19.1 ± 1.1%, and 74.5 ± 17.3% in single contaminated soil, respectively, compared to the control. Arsenic (78.8 ± 5.5% reduction compared to the control) and Pb (80.6 ± 13.4%) uptake as well as Sb (100.0 ± 0.0%) and Pb (12.2 ± 0.7%) uptake further reduced in mixed contaminated soil. In mixed contaminated soil, immobilization of metal(loid)s by IPCB was enhanced because of phosphate substitution by oxyanions reacted with Fe and subsequent immobilization of phosphate with Pb. In addition, increased soil pH by IPCB contributed to stabilization of metal(loid)s. The simultaneous stabilization of metal(loid)s and nutrient supply by IPCB mitigated adverse effects of metal(loid)s on plants and promoted plant growth, thereby remediating metal(loid)-contaminated soil.