Stabilization of fluorine-contaminated soil in aluminum smelting site with biochar loaded iron-lanthanide and aluminum-lanthanide bimetallic materials

• Published in: Journal of hazardous materials 2022-03, Vol.426, p.128072-128072, Article 128072
• Main Authors: Fan, Chuanfang, Yin, Naiyi, Cai, Xiaolin, Du, Xin, Wang, Pengfei, Liu, Xiaotong, Li, Yunpeng, Chang, Xuhui, Du, Huili, Ma, Jingnan, Cui, Yanshan
• Format: Article
• Language: English
• Subjects: Aluminum; Charcoal; F chemical speciation; F-contamination soil; Fluorides; Fluorine; Iron - analysis; Lanthanoid Series Elements; Soil; Soil Pollutants - analysis; Soil remediation; Trivalent metals-modified biochar; WSF
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.128072

Trivalent metals-modified-biochar (BC) has been widely used for the removal of fluorine (F) in water, but little is known about its effects on the stability and mobility of F-contaminated soil. Two types of modified-BC materials (BC-loaded iron-lanthanide (BC/Fe-La) and BC-loaded aluminum-lanthanide (BC/Al-La)) were synthesized and used for the remediation of F-contaminated soil. The forms of BC/LaxFe3x(OH)y in BC/Fe-La and BC/LaxAl3x(OH)y in BC/Al-La were identified by spectroscopy, X-ray dispersion, thermogravimetric, and pore diameter/volume analyses. Following application (4–12%, w/w) to F-contaminated soil for 30 d, water soluble fluoride (WSF) decreased significantly. The modified-BC with a 1:1:1 molar ratio (BC: Al3+ or Fe3+: La3+) were more effective than those at 1:0.5:0.5. The BC/Al-La were the most effective to stabilize F. In particular, the highest decrease in WSF (by 91.75%) was obtained with the application of 12% BC/Al-La-2, while 8% BC/Al-La-2% and 12% BC/Al-La-1 reduced the WSF by 87.58% and 90.17%, respectively; all values obtained were lower than the national standard of China (< 1.5 mg/L). In addition, the sequential extraction results showed that modified-BC promoted the transformation of the other chemical speciation to the Fe/Mn-F. [Display omitted] •Al-La and Fe-La modified-biochar were synthesized and used in F-contamination soil.•Al-La modified-biochar was the most effective material to stabilize fluorine in soil.•Al-La modified-biochar effectively decreased water-soluble fluoride by 91.75%.•Modified-biochar promoted the formation of Fe/Mn-F speciation in soil.