1
|
Ban R, Zha F, Kang B, Wu S, Song Y, Chen H. Mechanisms of enhancing MgO for stabilization/solidification of Pb-contaminated red clay through CO 2 sequestration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 366:121810. [PMID: 39002460 DOI: 10.1016/j.jenvman.2024.121810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 07/03/2024] [Accepted: 07/07/2024] [Indexed: 07/15/2024]
Abstract
Pb-contaminated soil poses significant environmental and health risks as well as soil stability issues. Research on sandy soils highlights CO2-enhanced reactive MgO as a promising solution for improving the solidification of Pb-contaminated soils. However, carbonation effects can differ markedly between soil types owing to varying soil properties. In this study, we evaluated the effects of CO2-enhanced reactive MgO on the engineering and environmental characteristics of Pb-contaminated red clay and explored its mechanism of carbonation solidification. The results showed that CO2-enhanced reactive MgO increased the strength of Pb-contaminated red clay to over 3 MPa within 1 h, which was approximately 25 times the strength of untreated soil (0.2 MPa) and significantly higher than that of reactive MgO-treated, uncarbonated soil (0.8 MPa). The pH of the carbonated soil (9-10) facilitated Pb2+ immobilization, and the increase over the initial parameter elevated the electrical conductivity value. Moreover, CO2-enhanced reactive MgO reduced the Pb2+ leaching concentration to below 0.1 mg/L, even at high Pb concentrations (10,000 mg/kg). Pb2+ transformed into lead carbonates during the carbonation process, with the hydrated magnesium carbonates forming a dense internal structure. This solidification mechanism included chemical precipitation, physical adsorption, and encapsulation. Notably, the carbonation time should be controlled within 1 h to prevent soil expansion. Together, these findings support the potential of CO2-enhanced reactive MgO for efficient and low-carbon application in the solidification of Pb-contaminated red clay.
Collapse
Affiliation(s)
- Rulong Ban
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Fusheng Zha
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China.
| | - Bo Kang
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China.
| | - Shan Wu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yu Song
- College of Civil and Architectural Engineering, Guilin University of Technology, Guilin, 541004, China
| | - Hongbin Chen
- College of Civil and Architectural Engineering, Guilin University of Technology, Guilin, 541004, China
| |
Collapse
|
2
|
Yadav P, Petrella A, Todaro F, De Gisi S, Vitone C, Petti R, Notarnicola M. Ex Situ Stabilization/Solidification Approaches of Marine Sediments Using Green Cement Admixtures. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3597. [PMID: 39063888 PMCID: PMC11278605 DOI: 10.3390/ma17143597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 07/15/2024] [Accepted: 07/19/2024] [Indexed: 07/28/2024]
Abstract
The routine dredging of waterways produces huge volumes of sediments. Handling contaminated dredged sediments poses significant and diverse challenges around the world. In recent years, novel and sustainable ex situ remediation technologies for contaminated sediments have been developed and applied. This review article focuses on cement-based binders in stabilizing contaminants through the stabilization/solidification (S/S) technique and the utilization of contaminated sediments as a resource. Through S/S techniques, heavy metals can be solidified and stabilized in dense and durable solid matrices, reducing their permeability and restricting their release into the environment. Industrial by-products like red mud (RM), soda residue (SR), pulverized fly ash (PFA), and alkaline granulated blast furnace slag (GGBS) can immobilize heavy metal ions such as lead, zinc, cadmium, copper, and chromium by precipitation. However, in a strong alkali environment, certain heavy metal ions might dissolve again. To address this, immobilization in low pH media can be achieved using materials like GGBS, metakaolin (MK), and incinerated sewage sludge ash (ISSA). Additionally, heavy metals can be also immobilized through the formation of silicate gels and ettringites during pozzolanic reactions by mechanisms such as adsorption, ion exchanges, and encapsulation. It is foreseeable that, in the future, the scientific community will increasingly turn towards multidisciplinary studies on novel materials, also after an evaluation of the effects on long-term heavy metal stabilization.
Collapse
Affiliation(s)
- Pravendra Yadav
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (P.Y.); (C.V.); (R.P.); (M.N.)
| | - Andrea Petrella
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (P.Y.); (C.V.); (R.P.); (M.N.)
| | - Francesco Todaro
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (P.Y.); (C.V.); (R.P.); (M.N.)
| | - Sabino De Gisi
- Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy;
| | - Claudia Vitone
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (P.Y.); (C.V.); (R.P.); (M.N.)
| | - Rossella Petti
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (P.Y.); (C.V.); (R.P.); (M.N.)
| | - Michele Notarnicola
- Department of Civil, Environmental, Land, Building Engineering and Chemistry (DICATECh), Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (P.Y.); (C.V.); (R.P.); (M.N.)
| |
Collapse
|
3
|
Huang X, Sun Z, Zhao Y, Wang H, Xue F, Hou H. Zero-carbon inertization processes of hazardous mine tailings: Mineral physicochemical properties, transformation mechanism, and long-term stability. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133882. [PMID: 38412646 DOI: 10.1016/j.jhazmat.2024.133882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/15/2024] [Accepted: 02/22/2024] [Indexed: 02/29/2024]
Abstract
Hazardous mine tailings (HMTs) dam failures can cause devastation to the ecology environment, people's lives and property, which require expensive and complicated remediation engineering systematacially. A cheap and sustainable inertization disposal is proposed for de-risking HMTs without any carbon emissions, stabilizing hazardous heavy metal cations within safety minerals and also sequestering CO2 in the process, simultaneously. Herein, lead-zinc tailings as target HMTs were inertized by using waste rice husk ashes (RHAs) and carbide slag (CS) with a certain ratio, and lead-zinc tailings hardened pastes (LZTHPs) were investigated based on the experimental performance, analytical characteristics, and simulation diffusion methods, to deeply unveil the minerals transformation mechanisms and long-term stability from the cation perspectives. Results revealed that LZTHPs' compressive strength ranged from 1.04-4.73 MPa and leaching toxicity concentrations of Pb, Zn, Cr, and Cd reached 0.03 mg/L, 1.78 mg/L, 0.01 mg/L, and 0.01 mg/L, respectively. C-S-H gels (Type I and II), cation hydroxides and CO2 mineralization carbonates were the hydrates in LZTHPs. Pb (86%), Zn (78%), Cr (76%), and Cd (65%) were immobilized as residual state, and CO2 mineralization capacity was 0.16 kg/kg. The diffusion coefficient of Pb, Zn, Cr, and Cd below 4.48 × 10-10 cm2/s, 1.39 × 10-10 cm2/s, 4.72 × 10-10 cm2/s, and 0.30 × 10-12 cm2/s, which would be sufficient in most scenarios to adequately stabilize tailings. Diffusion control is the leaching mechanism of cations. After 100 years of simulation diffusion, the diffusion areas of Pb, Zn, Cr, and Cd are 1.33 × 10-3∼1.49 cm2, 2.47 × 10-4∼0.48 cm2, 2.47-8.61 × 10-4 cm2, and 1.49 cm2, respectively, and the environmental impact of LZTHPs was negligible. This study provides promising solutions for alleviating hazardous tailings dangerous, achieving sustainable development with zero-carbon emission, implying the concept of eliminating waste by waste, synchronously.
Collapse
Affiliation(s)
- Xuquan Huang
- Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, PR China; College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, PR China
| | - Zhenghua Sun
- College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, PR China
| | - Yanhui Zhao
- Ecology and Environment Monitoring and Scientific Research Center, Yangtze Basin Ecology and Environment Administration, Ministry of Ecological and Environment, Wuhan 430010, PR China
| | - Haojie Wang
- Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, PR China; College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, PR China; School of Resource and Environment Science, Wuhan University, Wuhan 430072, PR China.
| | - Fei Xue
- Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, PR China; College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, PR China
| | - Haobo Hou
- School of Resource and Environment Science, Wuhan University, Wuhan 430072, PR China
| |
Collapse
|
4
|
Liu Y, Molinari S, Dalconi MC, Valentini L, Bellotto MP, Ferrari G, Pellay R, Rilievo G, Vianello F, Famengo A, Salviulo G, Artioli G. Industrial by-products-derived binders for in-situ remediation of high Pb content pyrite ash: Synergistic use of ground granulated blast furnace slag and steel slag to achieve efficient Pb retention and CO 2 mitigation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 345:123455. [PMID: 38301818 DOI: 10.1016/j.envpol.2024.123455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 12/19/2023] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
Ordinary Portland cement (OPC) is a cost-effective and conventional binder that is widely adopted in brownfield site remediation and redevelopment. However, the substantial carbon dioxide emission during OPC production and the concerns about its undesirable retention capacity for potentially toxic elements strain this strategy. To tackle this objective, we herein tailored four alternative binders (calcium aluminate cement, OPC-activated ground-granulated blast-furnace slag (GGBFS), white-steel-slag activated GGBFS, and alkaline-activated GGBFS) for facilitating immobilization of high Pb content pyrite ash, with the perspectives of enhancing Pb retention and mitigating anthropogenic carbon dioxide emissions. The characterizations revealed that the incorporation of white steel slag efficiently benefits the activity of GGBFS, herein facilitating the hydration products (mainly ettringite and calcium silicate hydrates) precipitation and Pb immobilization. Further, we quantified the cradle-to-gate carbon footprint and cost analysis attributed to each binder-Pb contaminants system, finding that the application of these alternative binders could be pivotal in the envisaged carbon-neutral world if the growth of the OPC-free roadmap continues. The findings suggest that the synergistic use of recycled white steel slag and GGBFS can be proposed as a profitable and sustainable OPC-free candidate to facilitate the management of lead-contaminated brownfield sites. The overall results underscore the potential immobilization mechanisms of Pb in multiple OPC-free/substitution binder systems and highlight the urgent need to bridge the zero-emission insights to sustainable in-situ solidification/stabilization technologies.
Collapse
Affiliation(s)
- Yikai Liu
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
| | - Simone Molinari
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy.
| | - Maria Chiara Dalconi
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
| | - Luca Valentini
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
| | | | | | - Roberto Pellay
- TEVGroup S.r.l., via Romea 8, 30034, Mira, Venice, Italy
| | - Graziano Rilievo
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020, Legnaro, Italy
| | - Fabio Vianello
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020, Legnaro, Italy
| | - Alessia Famengo
- Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia, Consiglio Nazionale delle Ricerche, C.so Stati Uniti 4, 35127, Padova, Italy
| | - Gabriella Salviulo
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
| | - Gilberto Artioli
- Department of Geosciences and CIRCe Centre, University of Padua, via G. Gradenigo 6, 35129, Padua, Italy
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Lee SJ, Han MH, Ahn YT, Jeon BH, Choi J. Assessment of effectiveness in stabilization/solidification of arsenic-contaminated soil: long-term leaching test and geophysical measurement. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:120472-120482. [PMID: 37943433 DOI: 10.1007/s11356-023-30641-2] [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: 06/13/2023] [Accepted: 10/19/2023] [Indexed: 11/10/2023]
Abstract
This study focused on evaluating the effectiveness of stabilizer/binding agents in immobilizing arsenic (As) in contaminated soil using both geochemical and geophysical monitoring methods. The effluent from the stabilizer/binding agent's application and control columns was analyzed, and the status of the columns was monitored using electrical resistivity (ER) and induced polarization (IP) methods. As stabilizers/binder, acid mine drainage sludge (AMDS) and steel slag (SS) were used, which delayed As and Ca leaching time and significantly reduced As leaching amount. Determination coefficients for As and Fe leaching exhibited elevated values (control column, R2 = 0.955; AMDS column, R2 = 0.908; and SS column, R2 = 0.833). A discernible decline in the concentration of leached Fe was accompanied by a corresponding reduction in IP. The determination coefficients correlating IP and Fe leaching remained substantial (control column, R2 = 0.768; AMDS column, R2 = 0.807; and SS column, R2 = 0.818). Such IP measurements manifest as instrumental tools in monitoring and assessing the retention capacity of applied stabilizer/binding agents in As-affected soils, thereby furnishing crucial data for the enduring surveillance of stabilization/solidification locales. This research posits a swift and continuous monitoring method for solidification/stabilization locales in situ.
Collapse
Affiliation(s)
- Sun-Jae Lee
- Korea Institute of Science and Technology (KIST), Sustainable Environment Research Center, Hwarang-Ro 14, Seongbuk-Gu, Seoul, 02792, South Korea
- Green School, Korea University, Seoul, 02841, Republic of Korea
| | - Man Ho Han
- Korea Radioactive Waste Agency, 174, Gajeong-Ro, Yuseong-Gu, Daejeon, Republic of Korea
| | - Yong-Tae Ahn
- Department of Civil & Energy System Engineering, Kyonggi University, Suwon, 16227, Republic of Korea
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Jaeyoung Choi
- Korea Institute of Science and Technology (KIST), Sustainable Environment Research Center, Hwarang-Ro 14, Seongbuk-Gu, Seoul, 02792, South Korea.
| |
Collapse
|
7
|
Liu J, Wu D, Tan X, Yu P, Xu L. Review of the Interactions between Conventional Cementitious Materials and Heavy Metal Ions in Stabilization/Solidification Processing. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16093444. [PMID: 37176327 PMCID: PMC10179848 DOI: 10.3390/ma16093444] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023]
Abstract
In the past few decades, solidification/stabilization (S/S) technology has been put forward for the purpose of improving soil strength and inhibiting contaminant migration in the remediation of heavy metal-contaminated sites. Cement, lime, and fly ash are among the most common and effective binders to treat contaminated soils. During S/S processing, the main interactions that are responsible for improving the soil's behaviors can be summarized as gelification, self-hardening, and aggregation. Currently, precipitation, incorporation, and substitution have been commonly accepted as the predominant immobilization mechanisms for heavy metal ions and have been directly verified by some micro-testing techniques. While replacement of Ca2+/Si4+ in the cementitious products and physical encapsulation remain controversial, which is proposed dependent on the indirect results. Lead and zinc can retard both the initial and final setting times of cement hydration, while chromium can accelerate the initial cement hydration. Though cadmium can shorten the initial setting time, further cement hydration will be inhibited. While for mercury, the interference impact is closely associated with its adapted anion. It should be pointed out that obtaining a better understanding of the remediation mechanism involved in S/S processing will contribute to facilitating technical improvement, further extension, and application.
Collapse
Affiliation(s)
- Jingjing Liu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Dongbiao Wu
- Anhui Urban Construction Design Institute Corp., Ltd., Hefei 230051, China
| | - Xiaohui Tan
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Peng Yu
- Anhui Urban Construction Design Institute Corp., Ltd., Hefei 230051, China
| | - Long Xu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| |
Collapse
|
8
|
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.
Collapse
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.
| |
Collapse
|
9
|
Yang Z, Zhang K, Li X, Ren S, Li P. The effects of long-term freezing-thawing on the strength properties and the chemical stability of compound solidified/stabilized lead-contaminated soil. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:38185-38201. [PMID: 36576635 DOI: 10.1007/s11356-022-24881-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
Solidification/stabilization (S/S) is the prevalent remediation technology for the treatment of heavy metal contaminated soils (HMCS). However, under the stress of complex surrounding environments, S/S effectiveness tends to deteriorate and freezing-thawing is one of the most influential natural forcings. The different proportions of cement, lime, and fly ash were used as the compound curing agents to treat solidified/stabilized HMCS with varying levels of lead contamination. The resulting samples were subjected to up to 180 freeze-thaw cycles (F-T) (1 day per cycle). Unconfined compressive strength (UCS) tests and semi-dynamic leaching tests were performed after F-T to explore the strength evolution of compound solidified/stabilized lead-contaminated soils (Pb-CSCS) and the chemical stability of the lead within. The results show that the F-T duration changes the strength deterioration mechanism of Pb-CSCS under F-T. There has been a shift in the main influencing factor from the promoted curing agent hydration by short-term F-T to the structural damage of the specimen induced by prolonged F-T. The variations in leachate pH, lead leachability, and diffusion ability with progressing F-T revealed a degradation effect of the changes in the physical states of water and crack propagation brought by F-T. These unfavorable changes in soil structure and chemistry reduce the acid resistance of Pb-CSCS. Notably, fly ash and cement facilitate the strength maintenance of Pb-CSCS under long-term F-T conditions. Curing formulations that included both cement and fly ash significantly increased the UCS of treated soils by up to 80.5% (3 F-T) under short-term F-T. In contrast, the curing formulation without fly ash lost 51.8% of its strength after 180 F-T conditions. For lead stabilization, cement and especially lime are favored. The results showed a 25% increase in the total proportion of lime and cement in the curing agent formulation, leading to a 41.4% reduction of lead leaching risk.
Collapse
Affiliation(s)
- Zhongping Yang
- School of Civil Engineering, Chongqing University, Chongqing, 400045, China
- Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing, 400045, China
- National Joint Engineering Research Centre for Prevention and Control of Environmental Geological Hazards in the TGR Area Chongqing University, Chongqing, 400045, China
| | - Keshan Zhang
- School of Civil Engineering, Chongqing University, Chongqing, 400045, China
- Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing, 400045, China
- National Joint Engineering Research Centre for Prevention and Control of Environmental Geological Hazards in the TGR Area Chongqing University, Chongqing, 400045, China
| | - Xuyong Li
- School of Civil Engineering, Chongqing University, Chongqing, 400045, China.
- Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing, 400045, China.
- National Joint Engineering Research Centre for Prevention and Control of Environmental Geological Hazards in the TGR Area Chongqing University, Chongqing, 400045, China.
| | - Shupei Ren
- School of Civil Engineering, Chongqing University, Chongqing, 400045, China
- Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing, 400045, China
- National Joint Engineering Research Centre for Prevention and Control of Environmental Geological Hazards in the TGR Area Chongqing University, Chongqing, 400045, China
| | - Peng Li
- School of Civil Engineering, Chongqing University, Chongqing, 400045, China
- Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing, 400045, China
- National Joint Engineering Research Centre for Prevention and Control of Environmental Geological Hazards in the TGR Area Chongqing University, Chongqing, 400045, China
| |
Collapse
|
10
|
Rozbahani M, Goodarzi AR, Lajevardi SH. Coupling effect of superfine zeolite and fiber on enhancing the long-term performance of stabilized/solidified Pb-contaminated clayey soils. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:4203-4218. [PMID: 35965302 DOI: 10.1007/s11356-022-22453-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
The focus of the present study was on the applicability of superfine zeolite (SZ) and polypropylene fibers in improving the geo-environmental parameters as well as the durability of cement-based stabilized/solidified low plasticity clay containing different dosages of Pb. The leaching data revealed that while adding a low range (≤ 7.5%) of sole cement even in the severely polluted soils could fully eliminate the Pb bioavailability, the metal retention capacity might portray a marked sensitivity to the acid-washing process. A major reduction was also observed in the mechanical/leaching performance of those samples after undergoing the wetting-drying (w-d) cycle, especially at a high proportion of Pb, which could weaken the cementation bonding dramatically; hence, much more cement was needed to pass the required stabilization/solidification (S/S) standards. Besides, the micro level tests indicated that the application of SZ (with 25% cement replacement) would alleviate the Pb declining impact on the S/S reactions and modify the porous network of soil. As a result, the specimens amended by cement-SZ (CSZ) were more functional (~ 1.4 times) in immobilizing the toxic ions than the cement alone was. However, the CSZ admixture might not perfectly restrain the w-d forces/deteriorations. Such a potential drawback was found to be solvable by the insertion of fiber, in which case, an enhancement in the ductility and the metal capsulation could be also manifested. In fact, the CSZ/fiber treatment could form a well-intertwined matrix, showing high success rates in stabilizing/solidifying the contaminated soils alongside a significant decrease (~ 2-folds) in the quantity of needed amount of cement to give the S/S satisfactory operation under the harsh environmental conditions.
Collapse
Affiliation(s)
- Mazaher Rozbahani
- Department of Civil Engineering, Arak Branch, Islamic Azad University, Arak, Iran
| | - Amir Reza Goodarzi
- Faculty of Engineering, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
| | | |
Collapse
|
11
|
Lal A, Fronczyk J. Does Current Knowledge Give a Variety of Possibilities for the Stabilization/Solidification of Soil Contaminated with Heavy Metals?-A Review. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8491. [PMID: 36499986 PMCID: PMC9736232 DOI: 10.3390/ma15238491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
Stabilization/solidification of contaminated soil is a process that allows simultaneous strengthening of the soil structure, disposal of contamination and recycling of industrial waste, implemented as substitutes for Portland cement or additives to improve the properties of the final product obtained. Extremely intensive development of studies pertaining to the S/S process prompted the authors to systematize the binders used and the corresponding methods of binding the contamination, and to perform an analysis of the effectiveness expressed in geomechanical properties and leachability. The study pays close attention to the types of additives and binders of waste origin, as well as the ecological and economic benefits of their use. The methods of preparing and caring for the specimens were reviewed, in addition to the methods of testing the effectiveness of the S/S process, including the influence of aging factors on long-term properties. The results of the analyses carried out are presented in the form of diagrams and charts, facilitating individual evaluation of the various solutions for the stabilization/solidification of soils contaminated with heavy metals.
Collapse
Affiliation(s)
- Agnieszka Lal
- Faculty of Civil Engineering and Architecture, Lublin University of Technology, 40 Nadbystrzycka Str., 20-618 Lublin, Poland
| | - Joanna Fronczyk
- Institute of Civil Engineering, Warsaw University of Life Sciences—SGGW, 166 Nowoursynowska Str., 02-787 Warsaw, Poland
| |
Collapse
|
12
|
Jiang Q, He Y, Wu Y, Dian B, Zhang J, Li T, Jiang M. Solidification/stabilization of soil heavy metals by alkaline industrial wastes: A critical review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 312:120094. [PMID: 36067972 DOI: 10.1016/j.envpol.2022.120094] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
Solidification/stabilization technology is one of the most desirable technologies for the remediation of heavy metal contaminated soils due to its convenience and effectiveness. The annual production of alkaline industrial wastes in China is in the hundreds of millions of tons. Alkaline industrial wastes have the potential to replace conventional stabilizers because of their cost effectiveness and performance in stabilizing heavy metals in soils. This paper systematically summarizes the use of four alkaline industrial wastes (soda residue, steel slag, carbide slag, and red mud) for the solidification/stabilization of heavy metal contaminated soils and provides a comprehensive analysis of the three mechanisms of action (hydration, precipitation, and adsorption) and factors that influence the process. In addition, the environmental risks associated with the use of alkaline industrial wastes are highlighted. We found that soda residues, steel slag and carbide slag are appropriate for solidification/stabilization of Pb, Cd, Zn and Cu, while red mud is a potential passivation agent for the stabilization of As in soils. However, implementation of remediation methods using alkaline industrial wastes has been limited because the long-term effectiveness, synergistic effects, and usage in soils containing multiple heavy metals have not been thoroughly studied. This review provides the latest knowledge on the mechanisms, risks, and challenges of using alkaline industrial wastes for solidification/stabilization of heavy metal contaminated soils.
Collapse
Affiliation(s)
- Qi Jiang
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Yongmei He
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Yonglin Wu
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Bo Dian
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Jilai Zhang
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Tianguo Li
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China
| | - Ming Jiang
- College of Resources and Environment, Yunnan Agricultural University, Kunming, 650201, China.
| |
Collapse
|
13
|
Xu DM, Fu RB. The mechanistic insights into the leaching behaviors of potentially toxic elements from the indigenous zinc smelting slags under the slag dumping site scenario. JOURNAL OF HAZARDOUS MATERIALS 2022; 437:129368. [PMID: 35897171 DOI: 10.1016/j.jhazmat.2022.129368] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 06/04/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Since lager quantities of the zinc (Zn) smelting slags were traditionally dumped at the indigenous Zn smelting sites, the release characterization of potentially toxic elements (PTEs) from the Zn smelting slags under various environmental conditions were of great significance for an environmental risk analysis. The acidification of the Zn smelting slags to pH= 4 and 6 would result in the leaching concentrations of Cd and Mn exceeding the fourth-class standard of surface water quality standard in China (GB3838-2002). Notably, most metals exhibited an amphoteric leaching pattern, where the highest leached concentrations of As, Cd, Cu, Mn, Pb, and Zn were 4.15, 4.21, 140.0, 78.1, 156.9 and 477.0 mg/L, respectively. In addition, the highest release of toxic metals within 96 h reached 0.17 % of As, 3.50 % of Cd, 2.77 % of Cu, 6.92 % of Mn, 0.13 % of Pb, and 2.57 % of Zn, respectively. The combined results of various characterization techniques suggested that the PTEs remobilization effected by rhizosphere-like organic acids were mainly controlled by the precipitation of newly formed Fe, Mn and Al (hydr) oxides and the complexation of organic ligands. The present study results could provide valuable insights into the long-term leaching behaviors of PTEs from the Zn smelting slags to reduce ecological hazard.
Collapse
Affiliation(s)
- Da-Mao Xu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Centre for Environmental Risk Management and Remediation of Soil and Groundwater, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| | - Rong-Bing Fu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Centre for Environmental Risk Management and Remediation of Soil and Groundwater, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| |
Collapse
|
14
|
Wang H, Ju C, Zhou M, Chen J, Kan X, Dong Y, Hou H. Acid rain-dependent detailed leaching characteristics and simultaneous immobilization of Pb, Zn, Cr, and Cd from hazardous lead-zinc tailing. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 307:119529. [PMID: 35623574 DOI: 10.1016/j.envpol.2022.119529] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/10/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
In acidic medium, hazardous heavy metals of lead-zinc tailing (LZT) are easily leachable and mobilizable. Thus, the hazard, amount, form, and complexity of the leached heavy metals under acidic precipitation become a major environmental concern. This work investigates the gangue minerals, toxicity, speciation, leaching characteristics of heavy metals in LZT under simulated acid rain, as well as immobilization effects and mechanisms using a sustainable binder. In LZT, dolomite, quartz, calcite, and muscovite are the main gangue minerals, tiny hazardous metallic minerals were absorbed in the surface. The results revealed that Pb, Zn, Cr, and Cd were the predominant harmful elements, particularly Pb and Zn. Zn is leached completely and is the concerned hazardous element under simulated acid rain. In the acid rain neutralization ability test, the amount of leachable Pb, Cr, Ca, and Si maintained in equilibrium, leached Zn, Cd, Al, and Mg depended on the addition of acid. Pb and Ca were sedimented in residues. Immobilization of Pb, Zn, Cr, and Cd depended on the stability of Ca(OH)2/C-S-H of hydrates, and 70% LZTHP after curing 7 days can be used for some practical engineering projects. This work opens up deeply understandings for the leached heavy metals under acidic precipitation and improves the sustainable and safe in the field of immobilization of heavy metals.
Collapse
Affiliation(s)
- Haojie Wang
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Chenxuan Ju
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Min Zhou
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China; Hubei Environmental Remediation Material Engineering Technology Research Center, Wuhan, 430072, PR China
| | - Jiaao Chen
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Xiaoqing Kan
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Yiqie Dong
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Haobo Hou
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China; Hubei Environmental Remediation Material Engineering Technology Research Center, Wuhan, 430072, PR China.
| |
Collapse
|
15
|
Hou R, Wang L, O'Connor D, Rinklebe J, Hou D. Natural field freeze-thaw process leads to different performances of soil amendments towards Cd immobilization and enrichment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154880. [PMID: 35364177 DOI: 10.1016/j.scitotenv.2022.154880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/07/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Cadmium (Cd) soil pollution is a global issue affecting crop production and food safety. Remediation methods involving in-situ Cd immobilization have been developed, but their effectiveness can diminish under seasonal freeze-thaw aging processes. In this study, we assessed the field performance of four soil treatments at a seasonally frozen rice paddy. Amendments were applied at 2 wt%, including: (i) sepiolite (a 2:1 clay mineral), (ii) superphosphate, (iii) biochar (produced by rice husk at 500 °C for 2 h), and (iv) joint application of biochar & superphosphate (1:1 mixture by weight). Immobilization performance was determined as DTPA extractable Cd and plant uptake in various organs. Overall, the four treatments significantly reduced Cd bioavailability during the plant growth period, with average DTPA-extractable concentrations decreasing by 43%, 34%, 39% and 45% for the four treatments, respectively, relative to untreated soil (control). Rice grain yields from the superphosphate and the joint application treatments increased by 8.0% and 11.8%, respectively, and Cd accumulation within those grains reduced by 14.3% and 48.9%, respectively. During the winter non-growth period, freeze-thaw aging facilitated Cd mobilization, with DTPA-extractable Cd increasing by 16.9% in the control soil, relative to the initial period. However, this reduced to 10.9%, 14.4%, 7.6% and 5.0%, for the sepiolite, superphosphate, biochar and joint application treatments, respectively. Overall, the joint application of biochar and superphosphate provided the best performance in terms of both long-term Cd immobilization and rice production enhancement, offering a green remediation option for risk management at Cd contaminated rice paddies in seasonally frozen regions.
Collapse
Affiliation(s)
- Renjie Hou
- School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; School of Environment, Tsinghua University, Beijing 100084, China
| | - Liuwei Wang
- School of Environment, Tsinghua University, Beijing 100084, China
| | - David O'Connor
- School of Real Estate and Land Management, Royal Agricultural University, Cirencester GL7 1RS, United Kingdom
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, Wuppertal 42285, Germany; Department of Environment, Energy and Geoinformatics, Sejong University, 98 Gunja-Dong, Seoul, Republic of Korea
| | - Deyi Hou
- School of Environment, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
16
|
Li L, Huang D, Gao Z, Cao G, Zhao R, Ma H, Li X, Li N, Zhang A. Transformation of hazardous zinc sludge into highly porous spinel/whisker-form mullite membranes for the separation of oil-in-water emulsions. Ann Ital Chir 2022. [DOI: 10.1016/j.jeurceramsoc.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
|
17
|
Wang H, Ju C, Zhou M, Chen J, Dong Y, Hou H. Sustainable and efficient stabilization/solidification of Pb, Cr, and Cd in lead-zinc tailings by using highly reactive pozzolanic solid waste. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 306:114473. [PMID: 35026710 DOI: 10.1016/j.jenvman.2022.114473] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Lead-zinc tailings (LZTs) are industrial by-products containing a large number of heavy metals that seriously harm the ecological environment and human health. This study was performed to propose a sustainable and efficient method for immobilizing Pb, Cr, and Cd in LZTs by using solid waste. To better assess the immobilization performance and mechanism, the leaching toxicity, fraction distribution, unconfined compressive strength, environmental risk assessment, and hydration products were explored. The LZTs were mixed and molded with different constituents of ground granulated blast furnace slag (GGBFS) and rice husk ashes (RHAs) at different curing temperatures. Results suggest that ≥99% of the Pb, Cr, and Cd were immobilized mainly in the form of residual fractions in the LZTs. The amounts of Pb, Cr, and Cd in the bioavailable fractions notably decreased by approximately 99.83%, 99.58%, and 97.05%, respectively. After stabilization/solidification (S/S) disposal, Pb, Cr, and Cd showed low to even no risk. The RHAs were effective to stabilize Pb, and GGBFS was effective to stabilize Cr. However, both materials showed almost equal effects to Cd. Ettringite, C-S-H gel, and portlandite were the main hydration products to immobilize Pb, Cr, and Cd, and these hydration products provided a source of strength. Honey-comb or reticular network C-S-H gel possessed higher specific surface area, higher pore volume, and bigger pore size than the other materials. The proposed method could explain the sustainability and efficiency of the S/S of Pb, Cr, and Cd in LZTs by using RHAs. This study opens up new perspectives for disposing heavy metal by using accessible agricultural solid waste (i.e., RHAs) in rural areas, and the solidified block shows certain economic benefits.
Collapse
Affiliation(s)
- Haojie Wang
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Chenxuan Ju
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Min Zhou
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China; Hubei Environmental Remediation Material Engineering Technology Research Center, Wuhan, 430072, PR China
| | - Jiaao Chen
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Yiqie Dong
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China
| | - Haobo Hou
- School of Resource and Environment Science, Wuhan University, Wuhan, 430072, PR China; Hubei Environmental Remediation Material Engineering Technology Research Center, Wuhan, 430072, PR China.
| |
Collapse
|
18
|
The Effects of the Long-Term Freeze–Thaw Cycles on the Forms of Heavy Metals in Solidified/Stabilized Lead–Zinc–Cadmium Composite Heavy Metals Contaminated Soil. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12062934] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Heavy metals (HMs) exist in nature in different forms, and the more unstable the form of an HM, the higher its toxicity and bioavailability. The content of HMs in stable fractions can increase significantly through the stabilization/solidification (S/S) technology. Still, external environments such as freeze–thaw (F–T) cycles will affect the stability of HMs directly. Therefore, a long-term F–T study of S/S Pb–Zn–Cd composite HM-contaminated soil was conducted under six conditions (0, 3, 7, 14, 30, and 90 cycles) with each F–T cycle process up to 24 h. The improved Tessier method was employed, and the results show that the S/S technology makes HMs transform to a more stable fraction. Still, the transformation efficiency is different for each HM. More than 98% of lead and zinc were converted to stable forms, while for cadmium, there are only 75.1%. Meanwhile, the S/S HMs were rapidly transformed into unstable forms at 0–14 cycles, but after 14 cycles, the transformation speed was significantly reduced. Among stable forms, it is mainly that the carbonate-bound fraction of HMs changes to unstable forms, and the characteristic peaks of carbonate stretching vibration were found at 874 cm−1, and 1420 cm−1 by Fourier infrared spectroscopy proves the presence of carbonate-bound substances. As a result of this study, the change trend of contaminated soil with S/S HMs under the effect of long-term F–T cycle was revealed, and the crisis point of pollution prevention and control was found, which provides some theoretical basis for the safety of soil remediation project.
Collapse
|
19
|
Stabilization/Solidification of Heavy Metals and PHe Contaminated Soil with β-Cyclodextrin Modified Biochar (β-CD-BC) and Portland Cement. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19031060. [PMID: 35162084 PMCID: PMC8834326 DOI: 10.3390/ijerph19031060] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/06/2022] [Accepted: 01/09/2022] [Indexed: 02/01/2023]
Abstract
Conventional stabilization/solidification materials have defects in the simultaneous treatment of heavy metals (HMs) and phenanthrene (PHe). In order to solve this problem, a new functional material β-cyclodextrin modified biochar (β-CD-BC) was prepared by integrating the properties of biochar (BC) and the hydrophilic and hydrophobic properties of the β-CD surface and combined with Portland cement (PC) to cure and stabilize HMs and PHe. The effect of key parameters on the treatment effect was discussed by response surface method. The results showed that the minimum leaching concentration if HMs was 16.81 mg·L-1, and the leaching concentration of PHe can be as low as 0.059 μg/kg under the conditions of β-CD-BC and Portland cement ratio of 9.75% and 11.4%, curing for 22.85 d. The weak acid soluble state reduced from 9~13% to 0.5~6%, the residual state was increased from 37~61% to 77~87%. The unconfined compressive strength of sample is more than 50 kPa. The results of this study can provide a new technical scheme for long-term curing and stabilization of HMs and PHe.
Collapse
|
20
|
Deniz MM, Erdem M. Effect of freezing-thawing cycles on the strength and pollutant leachability of stabilized/solidified metallurgical waste. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:49014-49031. [PMID: 33929668 DOI: 10.1007/s11356-021-14064-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
Stabilized/solidified hazardous wastes may lose their structural integrity and stability when exposed to long-term extreme weather conditions, such as repeated wetting-drying and freezing-thawing (F-T). This situation causes wastes to become environmentally risky again even if they are stabilized and solidified. In this study, the effects of F-T cycles on the strength and pollutant leachability of stabilization/solidification (S/S) products of zinc extraction residue (ZER) stabilized/solidified by Portland cement (PC), fly ash (FA), and alkaline phosphate (AP) were comprehensively investigated. S/S efficiency and F-T resistance of the samples were determined by unconfined compressive strength (UCS), and leaching tests widely applied in the USA (TCLP), European Union (EN-12457/1-4 2020), and Turkey (TS-EN 12457/4). In addition, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses and visual inspection were performed to examine the variations in mineralogical and morphological structures. S/S efficiency and F-T resistance changed depending on the type and amount of S/S reagent used and decreased in the order of PC+AP>PC>>FA. All applied S/S procedures, except for 10% PC addition, were found to be suitable for the S/S of ZER from the viewpoint of the achievement of the minimum required strength and pollutant leachability. F-T events did not change the mineralogical structures of the S/S products, but significantly reduced the UCS value by causing structural deformation. The pollutant concentrations released from the samples that lost their monolithic structure by crumbling after certain cycle increased with the increasing F-T cycle, causing a change in the storage criteria of the samples. Therefore, it is important to consider and apply the F-T cycle as a standard test in addition to the existing leaching and strength tests for S/S products of the wastes in terms of minimizing environmental risks.
Collapse
Affiliation(s)
- Mehmet Mustafa Deniz
- Department of Environmental Engineering, Fırat University, 23119, Elazığ, Turkey
| | - Mehmet Erdem
- Department of Environmental Engineering, Fırat University, 23119, Elazığ, Turkey.
| |
Collapse
|
21
|
Li X, Yang R, Li H, Yi H, Jing H. Experimental Study on Solidification and Stabilization of Heavy-Metal-Contaminated Soil Using Cementitious Materials. MATERIALS 2021; 14:ma14174999. [PMID: 34501089 PMCID: PMC8434242 DOI: 10.3390/ma14174999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 11/16/2022]
Abstract
In order to solve the shortcomings of the traditional curing agent in the treatment of composite heavy-metal-contaminated soil with the solidification and stabilization method, a new type of cementing material A was used as a curing agent, and the Pb, Cd, Cu composite heavy-metal-contaminated soil was artificially prepared to carry out an experimental study on solidification and stabilization (SS) restoration by the mechanical properties test, leaching performance test, and microscopic test. The results show that in the range of test dosage, with the increase in the curing agent content, the unconfined compressive strength of the solidified body increased, and the resistance to deformation was enhanced. From the perspective of leaching characteristics, the new curing agent A had an excellent curing effect on the composite heavy-metal-contaminated soil. To achieve safe disposal, a curing agent content of 10% applies only for the soil heavily contaminated by heavy metals. The curing agent A could significantly reduce the content of acid-extractable heavy metals after solidifying the heavy metal Pb, Cd, and Cu composite contaminated soil and effectively converted it into a residue state. The solidified phase contained hydrated products such as calcium silicate hydrate (CSH) and ettringite (AFt). These hydrated products can inhibit the leaching performance of heavy metal ions through adsorption, encapsulation, and ion exchange. The study provides a feasible method and reference for the solidification, restoration, and resource utilization of heavy-metal-contaminated soil in the subgrade.
Collapse
|
22
|
Yang Q, Cui P, Liu C, Fang G, Huang M, Wang Q, Zhou Y, Hou H, Wang Y. In situ stabilization of the adsorbed Co 2+ and Ni 2+ in rice straw biochar based on LDH and its reutilization in the activation of peroxymonosulfate. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:126215. [PMID: 34492972 DOI: 10.1016/j.jhazmat.2021.126215] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/17/2021] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
The stabilization of heavy metals adsorbed in the spent biochar remains a challenge, and the risk of secondary pollution under environmental changes will rise under inadequate post-treatment. Moreover, the safe and sufficient re-utilization of the spent biochar with heavy metals loaded have attracted extensive attention. In this research, the performance and mechanism of rice straw biochar (RSBC) pyrolyzed at different temperature for nickel and cobalt adsorption were investigated, and the stabilization of the adsorbed heavy metals was achieved via a simple two-step strategy: the adsorption of metal ions and the hydrothermal process to form the stable layered double hydroxides (LDH) on biochar, with a leaching rate below 0.005% evaluated by EPA toxicity characteristic leaching procedure (TCLP). Meanwhile, the stabilized RSBC-LDH can be reused as an excellent catalyst in the activation of peroxymonosulfate (PMS) to degrade organic pollutants efficiently. This work eliminated the risk of heavy metal desorption from the spent biochar, and enabled a new strategy for the optimized utilization of biochar in environmental remediation.
Collapse
Affiliation(s)
- Qiang Yang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; University of Chinese Academy of Science, 100049 Beijing, PR China
| | - Peixin Cui
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China
| | - Cun Liu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China
| | - Guodong Fang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China
| | - Meiying Huang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; University of Chinese Academy of Science, 100049 Beijing, PR China
| | - Qiuyue Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; College of Tropical Crops, Hainan University, 570100 Haikou, PR China
| | - Yiyi Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; University of Chinese Academy of Science, 100049 Beijing, PR China
| | - Hongbo Hou
- College of Environmental Science and Engineering, Central South University of Forestry and Technology, 410004 Changsha, PR China
| | - Yujun Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, PR China; University of Chinese Academy of Science, 100049 Beijing, PR China.
| |
Collapse
|