Remediation of antimony-contaminated soil with composite materials of Fe/Fe2+-fly ash-concrete additive in seasonal freezing regions

• Published in: Process safety and environmental protection Vol. 167; pp. 247 - 256
• Main Authors: Jiang, Miao, Wang, Kun, Xue, Ruiyuan, Zhao, Qingliang, Wang, Long, Wang, Weiye, Ding, Jing
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2022
• Subjects: Antimony-contaminated soil; Fe/Fe2+-fly ash-concrete additive; Freezing-thawing cycles; Leaching concentration; Solidification/stabilization; Unconfined compressive strength; C-S-H; RES; UCS; XANES; S-A; XRD; F-T; EXAFS; Fe/Fe2+-fly ash-concrete additive; AFT; W-D; SE; TCLP; ANOVA; S/S; CA; OM; Unconfined compressive strength; Ca-L; SDS; Leaching concentration; Fe-FA-CA; BDAT; Solidification/stabilization; Mont; USGS; Freezing-thawing cycles; CT; EXC; CAR; Antimony-contaminated soil; Fe/Mn; SEM; FA
• ISSN: 0957-5820; 1744-3598
• DOI: 10.1016/j.psep.2022.09.018

Antimony (Sb) finds its wide application in industries, however, the research on Sb solidification/stabilization (S/S) in the Sb-contaminated soil is currently insufficient, particularly in seasonal freezing regions. Here six composite materials of Fe/Fe2+-fly ash-concrete additive (Fe-FA-CA) were employed and optimized to remediate the Sb-contaminated soil subject to 40 freezing-thawing (F-T) cycles. After remediation, FeSO4-fly ash-calcium lignosulfonate (FFC) exhibited the best resistance performance to F-T. The stabilization efficiency was evaluated with TCLP at 92.92%. Meanwhile, Sb concentration met the criteria of landfill for inert waste assessed with the compliance test for leaching (CT) of European Standard. The S/S efficiency of Sb dropped slightly from 92.68% to 88.22% (TCLP) and from 97.18% to 93.37% (CT), respectively, after aging 40 F-T cycles. The fraction of residual Sb in the soil treated by FFC was increased by 10.41%, and the strength of the S/S soil was much higher than 350 kPa, the requirement of landfills in the U.S. during F-T cycles. Additionally, the poorly crystalline Fe in the soil remediated by FFC was increased by 4.54 g/kg, suppressing Sb migration. The feasibility and effectiveness of FFC in S/S of Sb demonstrated its potential to remediate Sb-contaminated soil in seasonal freezing regions. [Display omitted]