All Issue

2025 Vol.30, Issue 5 Preview Page
Evaluation of FeCl 3 -Based Washing Applicability for Pb-Contaminated Soils According to Stratigraphic Characteristics at a Military Shooting Range

군 사격장 층위별 특성에 따른 오염토양의 FeCl3기반 세척 적용성 평가

Nogil Kwak1
,
Jae-Woo Park1*
곽녹일 1
,
박재우 1*
1Department of Civil and Environmental Engineering, Hanyang University, Seoul 04763, South Korea
1한양대학교건설환경공학과
*Corresponding Author
31 October 2025. pp. 41-48
PDF XML Citation
Abstract

This research evaluated the applicability of FeCl 3 -based soil washing for Pb-contaminated soils collected from a military shooting range, focusing on stratigraphic differences. Through a systematic investigation of washing reagent type, concentration, liquid-to-solid ratio (L/S), agitation conditions, and magnetic separation intensity based on the subsoil (1.0-2.0 m), the optimal operating parameters were determined as FeCl 3 0.1 M, L/S = 1:3, 20 min, 300 rpm, and 6,000 G. Under these conditions, the subsoil showed removal efficiencies of 74.2% in the 2.00-0.85 mm particle range and 88.8% in the 0.85-0.15 mm range, Pb concentrations below the remediation standard (200 mg·kg- 1 ). In contrast, when the same conditions were applied to the topsoil (0.0-0.6 m) and intermediate soil (0.6-1.0 m), high variability in removal efficiency was observed due to the presence of particulate lead bullets and metallic residues, and the target standard could not be met even after repeated washing. Additional washing following density separation improved the topsoil and intermediate soil by approximately 60%; however, final concentrations remained over three times higher than the regulatory threshold. Statistical analysis confirmed that the difference in washing efficiency between the subsoil and the upper layers was significant (p < 0.005). Therefore, this study demonstrates that FeCl 3 washing alone is applicable for subsoil remediation, while for topsoil and intermediate layers, combined advanced separation processes are required. These findings provide a scientific basis for developing stratified remediation strategies for Pb-contaminated military sites.

Keywords
FeCl 3 washing
Soil remediation
Heavy metal contamination
Pb removal
References

References

1

Broomandi, P., Guney, M., Kim, J. R., Karaca, F. (2020). Soil contamination in areas impacted by military activities: A critical review. Sustainability, 12(21), 9002.

10.3390/su12219002
2

Cho, K., Kim, H., Purev, O., Choi, N., Lee, J. (2022). Physical separation of contaminated soil using a washing ejector based on hydrodynamic cavitation. Sustainability, 14(1), 252.

10.3390/su14010252
3

Cho, K., Myung, E., Kim, H., Park, C., Choi, N., Park, C., (2020). Effect of soil washing solutions on simultaneous removal of heavy metals and arsenic from contaminated soil. Int. J. Environ. Res. Public Health, 17(9), 3133.

10.3390/ijerph17093133
4

Deng, Y., Wang, S., Beadham, I., Gao, X., Ji, M., Wang, G., Zhang, C., Ruan, W. (2023). Effect of soil washing with an amino-acid-derived ionic liquid on the properties of Cd-contaminated paddy soil. Toxics, 11(3), 288.

10.3390/toxics11030288
5

Dong, H., Qiu, W., Liang, S., Wang, D., (2021). Mechanisms of FeCl3 washing for heavy-metal removal from soils: Hydrolysis, complexation and flocculation. J. Hazard. Mater., 403, 123-134.

6

Duan, J., Gregory, J., (2003). Coagulation by hydrolysing metal salts. Adv. Colloid Interface Sci., 100-102, 475-502.

10.1016/s0001-8686(02)00067-2
7

Guo, X., Wei, Z., Wu, Q., Li, Q., Wu, W., Zhang, C., (2016). Enhanced removal of heavy metals from contaminated soil using FeCl©ý washing coupled with subsequent stabilization. Environ. Sci. Pollut. Res., 23, 18902-18911.

8

Hou, D., Jia, X., Wang, L., McGrath, S. P., Zhu, Y.-G., Hu, Q., Zhao, F.-J., Bank, M. S., O¡¯Connor, D., Nriagu, J. (2025). Global soil pollution by toxic metals threatens agriculture and human health. Science, 388(6744), 316-321.

10.1126/science.adr5214
9

Li, T., Zhu, Z., Wang, D., Yao, C., Tang, H., (2006). Characterization of floc size, strength and structure under various coagulation mechanisms. Powder Technol., 168(2), 104-110.

10.1016/j.powtec.2006.07.003
10

Ministry of Environment (2022). Enforcement Rules of the Soil Environment Conservation Act, Appendix 3: Soil Contamination Concern Standards. National Law Information Center (Republic of Korea).

11

Nawrot, N., Wojciechowska, E., Matej-¨©ukowicz, K., Walkusz-Miotk, J., Pazdro, K., (2020). Spatial and vertical distribution analysis of heavy metals in urban retention tanks sediments: A case study of Strzyza Stream. Environ. Geochem. Health, 42, 1469-1485.

10.1007/s10653-019-00439-8
12

Niarchos, G., (2018). Electrodialytic remediation of PFAS-contaminated soil. MSc Thesis, Technical University of Denmark, Kongens Lyngby, 120 pp.

13

Oriekhova, O., Stoll, S. (2014). Investigation of FeCl©ý-induced coagulation processes using electrophoretic measurement, nanoparticle tracking analysis and dynamic light scattering: Importance of pH and colloid surface charge. Colloids Surf., A: Physicochem. Eng. Asp., 461, 212-219.

10.1016/j.colsurfa.2014.07.049
14

Ondrasek, G., Shepherd, J., Rathod, S., Dharavath, R., Rashid, M. I., Brtnicky, M., Shahid, M. S., Horvatinec, J., Rengel, Z., (2025). Metal contamination – A global environmental issue: Sources, implications & advances in mitigation. RSC Adv., 15(5), 3904-3927.

10.1039/d4ra04639k
15

Rinklebe, J., Shaheen, S. M., Tsang, D. C. W. (2020). Immobilization and phytoavailability of potentially toxic elements in contaminated soils using biochar and other amendments: A review. RSC Adv., 10, 21551-21574.

16

Su, C., Meng, J., Zhou, Y., Bi, R., Chen, Z., Diao, J., Huang, Z., Kan, Z., Wang, T., (2022). Heavy metals in soils from intense industrial areas in South China: Spatial distribution, source apportionment, and risk assessment. Front. Environ. Sci., 10, 820536.

10.3389/fenvs.2022.820536
17

Wang, X., Cairang, S., Du, J., Wei, Z., Wu, Q., Hu, L., Xu, M., (2025). A large-scale assessment of soil heavy metal pollution using field-collected earthworms as bio-indicators in Shaoguan, South China. Environ. Health, 3(6), 616-625.

10.1021/envhealth.4c00249
18

Zhang, W., Tong, L., Yuan, Y., Liu, Z., Huang, H., Tan, F., Qiu, R., (2010). Influence of soil washing with a chelator on subsequent chemical immobilization of heavy metals in a contaminated soil. J. Hazard. Mater., 178(1-3), 578-587.

10.1016/j.jhazmat.2010.01.124
Information
  • Publisher :The Korean Society of Soil and Groundwater Environment
  • Publisher(Ko) :한국지하수토양환경학회
  • Journal Title :Journal of Soil and Groundwater Environment
  • Journal Title(Ko) :지하수토양환경
  • Volume : 30
  • No :5
  • Pages :41-48
  • Received Date : 2025-08-25
  • Revised Date : 2025-09-29
  • Accepted Date : 2025-09-30
  • DOI :https://doi.org/10.7857/JSGE.2025.30.5.041
Journal Informaiton Journal of Soil and Groundwater Environment Journal of Soil and Groundwater Environment
Online Submission
  • KOFST
  • KISTI Current Status
  • KISTI Cited-by
  • orcid
  • open access
  • ccl
Journal Informaiton Journal Informaiton - close