Focusing on the two major problems of industrial solid waste accumulation and heavy metal contaminated soil, to explore the solidification effect and internal mechanism of a low-carbon curing agent used for treating 1% copper-contaminated soil. The changes in leaching concentration of copper ions and heavy metal forms in solidified soil were compared and analyzed. Meanwhile, the changes in the mechanical properties and microstructure of solidified soil were detected. The data indicates that the copper ion concentration of solidified soil after soaking complies with environmental safety requirements, and heavy metals transitioned from carbonate-bound state to iron-manganese oxidized state. The proportion of exchangeable and residual states in solidified soil do not change significantly, but their contents are different. In addition, soaking has a significant effect on improving the early strength of solidified soil and promoting the early hydration reaction. Microscopic results indicate that water curing promotes the formation of significant cementitious and needle-like substances in the solidified soil. The Fourier transform infrared spectrometer (FTIR) results show that the presence of O—H, C${O}_{3}^{2-}$, and Si—O/Al—O groups in the solidified soil. Comprehensive analysis shows the presence of conventional hydration products such as calcium carbonate and hydrated calcium silicate in the solidified soil, as well as the formation of ettringite under the action of phosphogypsum. As a result, the pores in the soil are effectively filled, and heavy metal ions are well encapsulated and adsorbed in the product, resulting in a leaching concentration of heavy metals that meet the requirements, while also promoting the strength of the solidified soil. The reasearch results provide a new approach for industrial solid waste, as well as a low-carbon and effective solidifier for the treatment of copper-contaminated soil, which has important environmental, economic, and social benefits.
SUO Chong-xian, DONG Xiao-qiang, DU Chuan-xin, JIN Ri-ya, XIE Ming-xing.
Influence of Soaking on the Safety Performance of High-concentration Copper-contaminated Soil Solidified by Low-carbon Material[J].
Science Technology and Engineering, 2026, 26(20): 8464-8471 DOI:10.12404/j.issn.1671-1815.2505499
WangG F, XiangJ, LiangG C, et al. Application of common industrial solid waste in water treatment: a review[J]. Environmental Science and Pollution Research, 2023, 30: 111766-111801.
[2]
LiY T, LiuG Y, LiW N, et al. Preparation, heavy-metal solidification mechanism and applications of glass-ceramics derived from solid wastes: a review[J]. Journal of the European Ceramic Society, 2025, 45: 117392.
[3]
WangS Y, LiuB, ZhangQ, et al. Application of geopolymers for treatment of industrial solid waste containing heavy metals: state-of-the-art review[J]. Journal of Cleaner Production, 2023, 390:136053.
[4]
WangX P, LuW D, RongL K, et al. Red mud as a green dephosphorization agent: co-reduction with high phosphorus oolitic hematite for iron extraction and dephosphorization[J]. Process Safety and Environmental Protection, 2025, 193: 990-1001.
[5]
YuC, YuZ K, Liao, RP, et al. B-nZVI optimization of strength and heavy metal stability of lead-contaminated soil solidified by portland cement[J]. Environmental Eochemistry and Health, 2024, 46: 383.
[6]
LiM G, TanH B, ZhangJ J, et al. Enhancement in compressive strength of carbide slag activated ground granulated blast furnace slag by introducing CaCl2 and NaCl[J]. Construction and Building Materials, 2023, 385: 131071.
[7]
LiangQ, ZhangM H, LiangC, et al. Modified red mud tailored to chromium contaminated soil remediation[J]. Journal of Environmental Chemical Engineering, 2023, 11: 109720.
CuiWenwen, DongXiaoqiang, LiuXiaoyong, et al. Hydration kinetics and hydration mechanism of red mud-based cementitious materials[J]. Rock and Soil Mechanics, 2025, 46(3): 867-880.
DuYunpeng, TongXiong, XieXian, et al. Current status and prospect of comprehensive utilization of valuable metal resources such as scandium in red mud[J]. Journal of the Chinese Society of Rare Earths, 2023, 41(2): 256-271.
ShenZhijie, LiJieqin, LiCaixia, et al. Pollution source apportionment of heavy metals in cultivated soil around a red mud yard based on APCS-MLR and PMF models[J]. Environmental Science, 2024, 45(2): 1058-1068.
[14]
WangM F, LiuX M. Applications of red mud as an environmental remediation material: a review[J]. Journal of Hazardous Materials, 2021, 408: 124420.
Wuhao, QinRui, LiYang, et al. Remediation of lead zinc mine polluted soil with red mud, silkworm sand, ferrous sulfate passivating agents[J]. Science Technology and Engineering, 2024, 24(36): 15725-15735.
HuYang, ZhouShiji, XuYang, et al. Field trial of solidifying/stabilizing multi-heavy metals-contaminated soil using phosphorus-based binders[J]. Chinese Journal of Geotechnical Engineering, 2026, 48(3): 560-568.
[19]
ChenH G, YangJ J. A new supplementary cementitious material: walnut shell ash[J]. Construction and Building Materials, 2023, 408: 133852.
[20]
WuY L, YangJ J, ChangR Q. The design of ternary all-solid-waste binder for solidified soil and the mechanical properties, mechanism and environmental benefits of CGF solidified soil[J]. Journal of Cleaner Production, 2023, 429: 139439.
TanYunzhi, WuXianqiao, WuJun, et al. Physical and mechanical properties of solidified sludge regulation with phosphogypsum-based aggregate[J]. Rock and Soil Mechanics, 2025, 46(6): 1667-1677.
DingJianwen, WanXing, GaoHongmei, et al. Mechanical behavior and microscopic mechanism of soft clay stabilized by red mud, phosphogypsum and cement[J]. Chinese Journal of Geotechnical Engineering, 2026, 48(3): 509-518.
WuWeijun, ZhangKunpeng, ZhangNing, et al. Road performance of red mud composite solidification agent for solidified silt and its mechanism[J]. Journal of Building Materials, 2025, 28(3): 227-235.
LuoXiaohong, ZhangShijun, GuoRongxin, et al. Effect of carbide slag instead of cement as alkali activator on properties and microstructure of excess-sulphate phosphogypsum cementitious material[J]. Materials Reports, 2023, 37(S2): 298-304.
[31]
ChewS H, KamruzzamanA H M, LeeF H. Physicochemical and engineering behavior of cement treated clays. Journal of Geotechnical and Geoenvironmental Engineering[J], Journal of Geotechnical and Geoenvironmental Engineering, 2004, 130: 696-706.
[32]
FirouzbakhtS, GitipourS, BaghdadiM, et al. Impact of hydrochar in stabilization/solidification of heavy metal-contaminated soil with portland cement[J]. Environmental Geochemistry and Health, 2024, 46: 1-22.
XiaoY X, HuangY J, YuM Z, et al. Stabilization effect of heavy metals in waste incineration fly ash by inorganic and organic chelating agents[J]. Water, Air, &Soil Pollution, 2025, 236: 1-13.
[36]
ChenT, WangL H, HeB, et al. Study on the solidification/stabilization of cadmium-contaminated soil by red mud-assisted blast furnace slag under excitation conditions[J]. Journal of Cleaner Production. 2024, 435: 140505.
ZhangYun, BaiLicheng, CaoShenggen, et al. The constraint mechanism of heavy metal ions precipitation-migration of gangue-based cement solidified filling body in the goaf[J]. Journal of Mining & Safety Engineering, 2026, 43(1): 35-47.
[39]
BaiB, ChenJ, BaiF, et al. Corrosion effect of acid/alkali on cementitious red mud-fly ash materials containing heavy metal residues[J]. Environmental Technology & Innovation, 2024, 33: 103485.
XiaWeiyi, FengYasong, DuYanjun, et al. Performance of hydroxyapatite based binder in ex-situ solidification/stabilization of heavy metal contaminated site soil[J]. Journal of Southeast University(Natural Science Edition), 2018, 48(3): 549-556.
[42]
HaiR, ZhengJ H, LiJ W, et al. Preparation mechanism and properties of thermal activated red mud and its geopolymer repair mortar[J]. Case Studies in Construction Materials, 2024, 20: e02853.
LiJianmin, ZhangJiayong, GuoLiwen. Pore fractal characteristics of the granulated blast furnace slag-carbide slag cementitious material and its effect on heavy metal adsorption[J]. Coal Science and Technology, 2025, 53(10): 294-304.