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Du Y, Shi L, Cao X, Zhao F, Hu P, Ying R, Gu S, Wu L, Luo Y, Christie P. Potential high-risk release sources of thallium and arsenic from surrounding rocks of a typical thallium and arsenic mining area in southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 935:173371. [PMID: 38772486 DOI: 10.1016/j.scitotenv.2024.173371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 05/23/2024]
Abstract
Abundant naturally and anthropogenically exposed surrounding rocks (NESRs and AESRs) in mining areas may pose persistent threats as sources of potentially toxic elements (PTEs), but this has been historically overlooked, especially for thallium (Tl) and arsenic (As). Here, the release risks of Tl and As from both NESRs and AESRs in a typical TlAs sulfide mining area were investigated. In a single leaching process, AESRs released 10.4 % of total Tl (157 μg L-1) and 32.5 % of total As (4089 μg L-1), 2-3 orders of magnitude higher than NESRs. Prolonged multiple leaching tests revealed notable and long-term risks of release of Tl and As from AESRs, associated with oxidation and dissolution of iron/sulfur-bearing minerals. Substantial release of PTEs was linked to the transformation/degradation of the -OH functional group and extensive dissolution of secondary sulfate minerals in AESRs. Ultrafiltration and STEM-EDS indicate that 18.4 % of water-extracted As released from AESRs existed as natural nanoparticles consisting of iron/sulfur-bearing minerals. This study highlights the high risks of Tl and As release from anthropogenically exposed surrounding rocks and the importance of nanoparticles in PTE transport, and provides insights into the control of PTEs in mining areas.
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Affiliation(s)
- Yanpei Du
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Lingfeng Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xinyan Cao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Fengqi Zhao
- College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China
| | - Pengjie Hu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China.
| | - Rongrong Ying
- State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, China.
| | - Shangyi Gu
- College of Resource and Environmental Engineering, Guizhou University, Guiyang 550025, China
| | - Longhua Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
| | - Yongming Luo
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
| | - Peter Christie
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China
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Deng W, Fu P, Li J, Wang X, Zhang Y. Effect of long-term dry-wet circulations on the Solidification/stabilization of Municipal solid waste incineration fly ash using a novel cementitious material. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:24302-24314. [PMID: 38441736 DOI: 10.1007/s11356-024-32742-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 02/28/2024] [Indexed: 04/07/2024]
Abstract
Solidification/stabilization (S/S) is a typical technique to immobilize toxic heavy metals in Municipal solid waste incineration fly ash (MSWI FA). This study utilized blast furnace slag, steel slag, desulfurization gypsum, and phosphoric acid sludge to develop a novel metallurgical slag based cementing material (MSCM). Its S/S effects of MSWI FA and long-term S/S effectiveness under dry-wet circulations (DWC) were evaluated and compared with ordinary Portland cement (OPC). The MSCM-FA block with 25 wt.% MSCM content achieved 28-day compressive strength of 9.38 MPa, indicating its high hydration reactivity. The leaching concentrations of Pb, Zn and Cd were just 51.4, 1895.8 and 36.1 μg/L, respectively, well below the limit standard of Municipal solid wastes in China (GB 16889-2008). After 30 times' DWC, leaching concentrations of Pb, Zn and Cd for MSCM-FA blocks increased up to 130.7, 9107.4 and 156.8 μg/L, respectively, but considerably lower than those for OPC-FA blocks (689, 11,870.6 and 185.2 μg/L, respectively). The XRD and chemical speciation analysis revealed the desorption of Pb, Zn and Cd attached to surface of C-S-H crystalline structure during the DWC. The XPS and SEM-EDS analysis confirmed the formation of Pb-O-Si and Zn-O-Si bonds via isomorphous replacement of C-A-S-H in binder-FA blocks. Ettringite crystalline structure in OPC-FA block was severely destructed during the DWC, resulting in the reduced contents of PbSO4 and CaZn2Si2O7·H2O and the higher leachability of Pb2+ and Zn2+.
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Affiliation(s)
- Wei Deng
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Pingfeng Fu
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
| | - Jia Li
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xiaoli Wang
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yuliang Zhang
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, 100083, China
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Deng T, Fisonga M, Ke H, Li L, Wang J, Deng Y. Mixing uniformity effect on leaching behaviour of cement-based solidified contaminated clay. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:167957. [PMID: 37866593 DOI: 10.1016/j.scitotenv.2023.167957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 10/24/2023]
Abstract
Mixing uniformity is essential for the quality control of the contaminated clay's solidification. To investigate the effect of the mixing uniformity on the leaching behaviour of the cement-based solidified contaminated clay, this study proposed a quantitative method to characterize the mixing uniformity and investigated the leaching behaviour by the leaching toxicity tests and semi-dynamic leaching tests. X-ray computed tomography (X-CT) was employed to reveal the internal mesoscopic structure. In this case, Pb2+ was selected as a tagged pollutant because of the widespread attention at heavy metal-contaminated sites. The leaching toxicity indicates the significant Pb2+ concentration deviation among the parallel specimens and non-association with the mixing uniformity. However, the Pb2+ cumulative leaching mass and observed diffusion coefficient by the semi-dynamic leaching tests both decrease with the mixing uniformity. X-CT image analysis reveals that the high cement zones wrap the low cement zones with different dimensions in the heterogeneous solidified matrix. Moreover, the specimen pretreatment method in the existing leaching toxicity standards may be inadequate because of the overall encapsulation destruction by the crushing process and representativeness uncertainty when sampling. However, for semi-dynamic leaching, the Pb2+ migration depends on the uniformity, reflecting the continuous distribution of high cement zones.
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Affiliation(s)
- Tingting Deng
- Institute of Geotechnical Engineering, School of Transportation, Southeast University, Nanjing 211189, China
| | - Marsheal Fisonga
- Institute of Geotechnical Engineering, School of Transportation, Southeast University, Nanjing 211189, China
| | - Han Ke
- School of Civil Engineering, Zhejiang University, Hangzhou 310058, China
| | - Ling Li
- CECEP DADI Environmental Remediation Co., Ltd., Beijing 100085, China
| | - Jianwei Wang
- CECEP DADI Environmental Remediation Co., Ltd., Beijing 100085, China
| | - Yongfeng Deng
- Institute of Geotechnical Engineering, School of Transportation, Southeast University, Nanjing 211189, China.
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Chen L, Nakamura K, Hama T. Review on stabilization/solidification methods and mechanism of heavy metals based on OPC-based binders. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 332:117362. [PMID: 36716545 DOI: 10.1016/j.jenvman.2023.117362] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
Stabilization/solidification (S/S) with ordinary portland cement (OPC)-based binders is a suitable method to remediate heavy metal (HM)-contaminated soil and reuse resources of industrial wastes. In industrial wastes, alkaline wastes such as red mud (RM), soda residue (SR), pulverized fly ash (PFA), and alkalinity granulated blast furnace slag (GGBS) can immobilize HM ions (Pb2+, Zn2+, Cd2+, Cr3+, and Cu2+) by precipitation. However, some HM ions (such as AsO43-) would redissolve within the strong alkali environment. In this case, PFA, GGBS, metakaolin (MK), and incinerated sewage sludge ash (ISSA) which have low pH, can be used to immobilize HM ions or added to the OPC-based binders to adjust the pH in the soil products. Moreover, the calcium silicate hydrate (CSH), calcium aluminum silicate hydrate (CASH), ettringite (AFt), and calcium monosulfoalumiante hydrates (AFm) generated during the pozzolanic reaction can also immobilize HM ions by adsorption on the surface, ion exchange, and encapsulation. SR and GGBS can be used to immobilize the HMs (such as CrO42- and AsO43-), which are mainly affected by AFt and AFm. For those not affected by AFt and AFm but related to immobilization by precipitating (such as Mn2+), other wastes except SR and GGBS are suitable for treating contaminated soil. Nevertheless, the formation of AFt is also instrumental for soil product strength. There are several factors affecting soil product strength. In the future, the influence of different hydration products on the S/S effects, competitive adsorption of HM ions, effects on long-term HM stabilization, and novel materials are worth being explored by researchers.
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Affiliation(s)
- Liyuan Chen
- Graduate School of Agriculture, Kyoto University Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 , Japan.
| | - Kimihito Nakamura
- Graduate School of Agriculture, Kyoto University Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 , Japan.
| | - Takehide Hama
- Graduate School of Agriculture, Kyoto University Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 , Japan.
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Study on the Mechanical and Leaching Characteristics of Permeable Reactive Barrier Waste Solidified by Cement-Based Materials. MATERIALS 2021; 14:ma14226985. [PMID: 34832385 PMCID: PMC8625049 DOI: 10.3390/ma14226985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 11/25/2022]
Abstract
The durability against wet-dry (w-d) cycles is an important parameter for the service life design of solidified permeable reactive barrier (PRB) waste. This study introduces the potential use of cement, fly ash, and carbide slag (CFC) for the stabilization/solidification (S/S) of PRB waste. In this study, solidified PRB waste was subjected to different w-d cycles ranging in times from 0 to 10. By analyzing the mass loss, the unconfined compressive strength (UCS), initial resistivity (IR), and the Mn2+ leaching concentration under different durability conditions, the results demonstrate that these variables increased and then tended to decrease with the number of w-d cycles. The UCS of contaminated soil is significantly correlated with IR. Moreover, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses indicate that the hydration products calcium silicate hydrate (C-S-H) and ettringite (AFt) are the main reasons for the enhancement of the UCS. However, the increase in Mn2+ concentration leads to a decrease in hydration products and the compactness of solidified soil, which has negative effects for the UCS and the leaching ion concentration. In general, the durability exhibited by the PRB waste treated with S/S in this paper was satisfactory. This study can provide theoretical guidance for practical engineering applications.
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