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Zou Z, Qin Y, Zhang T, Tan K. Enhancing road performance of lead-contaminated soil through biochar-cement solidification: An experimental study. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 348:119315. [PMID: 37844401 DOI: 10.1016/j.jenvman.2023.119315] [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: 04/13/2023] [Revised: 09/22/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023]
Abstract
The effectiveness of cement-based solidification for remediating heavy metal-contaminated soil diminishes at high levels of contamination. To overcome this limitation, the potential of a biochar-cement composite curing agent to enhance the properties of Pb 2+ contaminated soil was investigated in this study. The permeability, unconfined compressive strength (UCS), and leaching characteristics of the biochar-cement composite material were assessed under varying biochar contents. The results revealed that the addition of 1-5 wt% biochar in cement significantly improved the UCS of the solidified soil. However, excessive biochar contents had a detrimental effect on the strength of samples. Additionally, the incorporation of 3.0% biochar reduced the hydraulic conductivity and porosity to 7.75 × 10-9 cm/s and 43.12%, respectively. Moreover, the biochar-cement composite material exhibited remarkable efficiency in treating highly concentrated Pb2+ contaminated soil, with leaching concentration decreasing significantly with increasing biochar content, falling below the Chinese hazardous waste identification standard. Overall, the utilization of a biochar-cement composite curing agent in the solidification of heavy metal-contaminated soil could be considered a promising subgrade filler technique.
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Affiliation(s)
- Zhenjie Zou
- College of Civil Engineering and Architecture, Guangxi University, 100 University Road, Nanning, Guangxi, 530004, China
| | - Yinghong Qin
- College of Civil Engineering and Architecture, Guangxi University, 100 University Road, Nanning, Guangxi, 530004, China
| | - Tongsheng Zhang
- School of Materials Science and Engineering, South China University of Technology, 510640, Guangzhou, China
| | - Kanghao Tan
- College of Civil Engineering and Architecture, Guangxi University, 100 University Road, Nanning, Guangxi, 530004, China; School of Materials Science and Engineering, South China University of Technology, 510640, Guangzhou, China.
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2
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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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Guo X, Zhang W, Yu H, Jin D. Reduction, stabilization, and solidification of Cr(VI) in contaminated soils with a sustainable by-product-based binder. CHEMOSPHERE 2022; 307:135902. [PMID: 35948102 DOI: 10.1016/j.chemosphere.2022.135902] [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: 03/14/2022] [Revised: 07/24/2022] [Accepted: 07/30/2022] [Indexed: 06/15/2023]
Abstract
This study evaluated the use of a sustainable GFD binder for the stabilization/solidification (S/S) of chromium VI (Cr(VI))-contaminated soil. The GFD binder was composed of ground granulated blast furnace slag (GGBFS), fly ash and desulfurization ash, named after the initials of the three materials. The effects of curing time and binder dosage on soil unconfined compressive strength (UCS), Cr leachability, soil pH, and reduction ratio of Cr (VI) were tested. The immobilization mechanisms of Cr(VI) in contaminated soil were further explored using X-ray diffraction (XRD), scanning electron microscopy (SEM), and sequential extraction procedure (SEP). The results showed that the UCS and pH of the soil increased substantially after the GFD binder was added. After 28 days of curing with a 20% binder dosage, the leached total Cr concentration decreased from 34.4 mg/L in the contaminated soil to 1.44 mg/L in the treated soil, and the leached Cr(VI) concentration decreased from 28.0 mg/L to 0.45 mg/L. A Cr(VI) reduction ratio of 96.2% was achieved, indicating the strong reducibility of GGBFS. XRD revealed that the main hydration products of the GFD binder were hydrated calcium silicate (C-S-H) and ettringite. SEM results showed that the formation of hydration products and Cr-bearing precipitates filled the soil pores, resulting in a dense soil structure. The SEP results demonstrated that the levels of the unstable fraction F1 decreased considerably, and that the levels of the stable fractions F3 and F5 increased after treatment. Encapsulation by C-S-H, reduction by sulfides, adsorption of C-S-H, and precipitation of Cr-bearing hydroxides were the main mechanisms involved in Cr immobilization using the GFD binder.
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Affiliation(s)
- Xingzhang Guo
- School of Mechanics and Engineering Science, Shanghai University, 200444, Shanghai, PR China.
| | - Wenjie Zhang
- School of Mechanics and Engineering Science, Shanghai University, 200444, Shanghai, PR China.
| | - Haisheng Yu
- School of Mechanics and Engineering Science, Shanghai University, 200444, Shanghai, PR China.
| | - Dian Jin
- School of Mechanics and Engineering Science, Shanghai University, 200444, Shanghai, PR China.
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Zhang H, Zhao Y, Hou D, Hao H. Cementitious binders modified with halloysite nanotubes for enhanced lead immobilization. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2021.09.068] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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5
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Zha F, Liu C, Kang B, Yang X, Zhou Y, Yang C. Acid rain leaching behavior of Zn-contaminated soils solidified/stabilized using cement-soda residue. CHEMOSPHERE 2021; 281:130916. [PMID: 34029961 DOI: 10.1016/j.chemosphere.2021.130916] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/25/2021] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
Cement-soda residue (CSR) has been proven to be an effective binder for treating heavy metal-contaminated soils, and the durability is its most important characteristic. In this study, the effects of acid rain (AR) on the leaching behavior of CSR-solidified/stabilized, zinc-contaminated soils were investigated using flexible-wall soil column leaching tests. After leaching, some parameters were determined such as the unconfined compressive strength (UCS) and permeability coefficient of the samples, the concentrations of Zn2+ and Ca2+ in the filtrate. The test results showed that after AR leaching, the UCS of the solidified soil samples decreased and the permeability coefficient increased, while the zinc concentration in the filtrate always met the third grade of the applicable standard, the Chinese National Environmental Quality Standards (<1 mg⋅L-1). To reveal the binding mechanism, scanning electron microscopy (SEM) and mercury intrusion testing (MIP) were used to observe the microscopic characteristics of the soil samples. At the micro scale, the MIP and SEM results confirmed that the hydration products in the soil samples-hydrated calcium silicate, calcium hydroxide, and calcium zincate hydrate-partially dissolved during AR leaching, resulting in the loss of their internal structure. Consequently, the high alkalinity of the soda residue contributed to H+ neutralization in the AR leaching agent, indicating that soda residue can not only solidify heavy metal zinc ions effectively but can also buffer the erosive effect of AR on soil.
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Affiliation(s)
- Fusheng Zha
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Congmin Liu
- 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.
| | - Xiuhong Yang
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yang Zhou
- Anhui Urban Construction Engineering Co., Ltd, Hefei, 230002, China
| | - Chengbin Yang
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, China
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The Solidification/Stabilization of Wastewater (From a Landfill Leachate) in Specially Designed Binders Based on Coal Ash. MATERIALS 2021; 14:ma14195610. [PMID: 34640021 PMCID: PMC8510009 DOI: 10.3390/ma14195610] [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: 08/10/2021] [Revised: 09/07/2021] [Accepted: 09/23/2021] [Indexed: 11/22/2022]
Abstract
The aim of this study is to assess the possibility to solidify/stabilize a liquid waste from a municipal waste landfill using binders based on coal ash (fly ash and bottom ash) and specially designed cements for waste treatment (INERCEM). The leaching test proved that all cementitious systems are efficient for the solidification/stabilization of the studied wastes and can reduce the leaching potential of heavy metals present in both liquid waste and coal ash. Therefore, these wastes cease to be a source of environmental pollution. X-ray diffraction (XRD) and thermal complex analysis (DTA-TG) were used to assess the nature and amount of compounds formed in these cementitious systems during the hydration and hardening processes; ettringite, calcium silicate hydrates and CaCO3 were the main compounds formed in these systems assessed by these methods. The microstructure of hardened specimens was assessed by scanning electronic microscopy (SEM); the presence of hydrate phases, at the surface of cenospheres present in fly ash, proved the high pozzolanic reactivity of this phase.
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Abdelrahman MS, Nassar SH, Mashaly H, Mahmoud S, Maamoun D, Khattab TA. Polymerization products of lactic acid as synthetic thickening agents for textile printing. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127421] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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8
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Low-Carbon Binder for Cemented Paste Backfill: Flowability, Strength and Leaching Characteristics. MINERALS 2019. [DOI: 10.3390/min9110707] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Blast furnace slag was used as the main raw material to prepare the alkali activated slag (AAS), a low-carbon binder, for cemented paste backfill (CPB). The optimum parameters for preparing the AAS binders using an orthogonal experiment were obtained. Under the optimum conditions (NaOH content was 3 wt. %, Ordinary Portland cement (OPC) content was 7 wt. %, and gypsum dosage was 4 wt. %), the 28 days compressive strength of the binder was 29.55 MPa. The flow ability of the fresh CPB slurry decreased with solid content due to the increased yield stress, while the flow ability increased when rising the binder dosage. A predictive model for the compressive strength of CPB samples was reached through multivariate analysis and the R2 values were higher than 0.9. Sensitivity analysis showed that the solid content is the most important parameter which influences on the development of the CPB strength with a correlation coefficient of 0.826. From the Toxicity Characteristic Leaching Procedure (TCLP) tests, the leaching concentrations of Pb and Cd were below the threshold. As a result, the AAS has potential application as an alternative binder and cemented paste backfill.
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9
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Zhang M, Yang C, Zhao M, Yu L, Yang K, Zhu X, Jiang X. Immobilization of Cr(VI) by hydrated Portland cement pastes with and without calcium sulfate. JOURNAL OF HAZARDOUS MATERIALS 2018; 342:242-251. [PMID: 28843168 DOI: 10.1016/j.jhazmat.2017.07.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 06/10/2017] [Accepted: 07/19/2017] [Indexed: 06/07/2023]
Abstract
This work aims to illustrate the impact of high concentrations of Cr(VI) (based on Na2CrO4) on the hydration assembly and microstructural development of hydrated Portland cement, and the results also present the role of calcium sulfate on the immobilization of Cr(VI) in Portland cement. The results showed that the immobilization of Cr(VI) in hydrated Portland cement was attributed to the formation of CrO4-U phase, an analogue of SO4-U phase (3CaO·Al2O3·CaSO4·0.5Na2SO4·15H2O). The growth of CrO4-U phase on the surface of clinker particles formed a diffusion barrier and hence increased the setting time. Increasing the calcium sulfate dosage impaired the Cr(VI) immobilization due to the competition between CrO42- and SO42- integrated into the U phase. The generalized acid neutralization capacity (GANC) test indicated that the Cr(VI) leaching behavior was a function of the leachate pH value. As the pH decreased to 11.8, the CrO4-U phase was converted quickly to CrO4-ettringite, which generated a slight increase in Cr(VI) concentration. The most leaching sector, approximately 89.3% of added Cr (1wt% of cement), was found in the pH range 11.8-10.5 due to the dissolution of secondary CrO4-ettringite. It could also be shown that the C-S-H had little chemical binding for Cr(VI).
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Affiliation(s)
- Mingtao Zhang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China
| | - Changhui Yang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China.
| | - Min Zhao
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China
| | - Linwen Yu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China
| | - Kai Yang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China
| | - Xiaohong Zhu
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China.
| | - Xing Jiang
- College of Materials Science and Engineering, Chongqing University, Chongqing 400045, PR China
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10
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Guo B, Liu B, Yang J, Zhang S. The mechanisms of heavy metal immobilization by cementitious material treatments and thermal treatments: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 193:410-422. [PMID: 28238544 DOI: 10.1016/j.jenvman.2017.02.026] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 01/22/2017] [Accepted: 02/11/2017] [Indexed: 06/06/2023]
Abstract
Safe disposal of solid wastes containing heavy metals is a significant task for environment protection. Immobilization treatment is an effective technology to achieve this task. Cementitious material treatments and thermal treatments are two types of attractive immobilization treatments due to that the heavy metals could be encapsulated in their dense and durable wasteforms. This paper discusses the heavy metal immobilization mechanisms of these methods in detail. Physical encapsulation and chemical stabilization are two fundamental mechanisms that occur simultaneously during the immobilization processes. After immobilization treatments, the wasteforms build up a low permeable barrier for the contaminations. This reduces the exposed surface of wastes. Chemical stabilization occurs when the heavy metals transform into more stable and less soluble metal bearing phases. The heavy metal bearing phases in the wasteforms are also reviewed in this paper. If the heavy metals are incorporated into more stable and less soluble metal bearing phases, the potential hazards of heavy metals will be lower. Thus, converting heavy metals into more stable phases during immobilization processes should be a common way to enhance the immobilization effect of these immobilization methods.
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Affiliation(s)
- Bin Guo
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Bo Liu
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China.
| | - Jian Yang
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Shengen Zhang
- Institute for Advanced Materials and Technology, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
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11
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Ledesma EF, Jiménez JR, Ayuso J, Fernández JM, Brito JD. Experimental study of the mechanical stabilization of electric arc furnace dust using fluid cement mortars. JOURNAL OF HAZARDOUS MATERIALS 2017; 326:26-35. [PMID: 27987447 DOI: 10.1016/j.jhazmat.2016.11.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 06/06/2023]
Abstract
This article shows the results of an experimental study carried out in order to determine the maximum amount of electric arc furnace dust (EAFD) that can be incorporated into fluid cement-based mortars to produce mechanically stable monolithic blocks. The leaching performance of all mixes was studied in order to classify them according to the EU Council Decision 2003/33/EC. Two mortars were used as reference and three levels of EAFD incorporation were tested in each of the reference mortars. As the incorporation ratio of EAFD/cement increases, the mechanical strength decreases. This is due to the greater EAFD/cement and water/cement ratios, besides the presence of a double-hydrated hydroxide of Ca and Zn (CaZn2(OH)6·2H2O) instead of the portlandite phase (Ca(OH)2) in the mixes made with EAFD, as well as non-hydrated tricalcium silicate. A mass ratio of 2:1 (EAFD: cement-based mortar) can be added maintaining a stable mechanical strength. The mechanical stabilization process also reduced the leaching of metals, although it was not able to reduce the Pb concentration below the limit for hazardous waste. The high amount of EAFD mechanically stabilized in this experimental study can be useful to reduce the storage volume required in hazardous waste landfills.
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Affiliation(s)
- E F Ledesma
- Área de Mecánica de los Medios Continuos y Teoría de Estructuras, Universidad de Córdoba, España
| | - J R Jiménez
- Área de Ingeniería de la Construcción, Universidad de Córdoba, España.
| | - J Ayuso
- Área de Ingeniería de la Construcción, Universidad de Córdoba, España
| | - J M Fernández
- Área de Química Inorgánica, Universidad de Córdoba España
| | - J de Brito
- CERIS-ICIST, DECivil, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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12
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Zhang M, Yang C, Zhao M, Yang K, Shen R, Zheng Y. Immobilization potential of Cr(VI) in sodium hydroxide activated slag pastes. JOURNAL OF HAZARDOUS MATERIALS 2017; 321:281-289. [PMID: 27637094 DOI: 10.1016/j.jhazmat.2016.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 09/05/2016] [Accepted: 09/08/2016] [Indexed: 06/06/2023]
Abstract
This study investigated the immobilization potential of alkali-activated slag (AAS) pastes for Cr(VI) by examining compressive strength, toxicity characteristic leaching procedure (TCLP) and generalized acid neutralization capacity tests. Alkaline digestion, total acid digestion, XRD, FTIR and SEM-EDS were carried out to clarify the immobilization mechanism. The AAS pastes gave high compressive strengths, which contributed to the physical encapsulation of Cr. The addition of Cr(VI) induced an increase in compressive strength compared to Cr(VI)-free pastes. The leaching results showed that AAS pastes exhibited effective immobilization for Cr(VI) and that the leachability was strongly dependent on the NaOH dosage, water to slag ratio, initial Cr(VI) content, leachate pH and curing duration. The initial Cr(VI) content up to 1.5wt% by weight of slag was well immobilized with the total-Cr leachability below the TCLP regulatory limit of 5mg/L. The digestion results demonstrated that the reduction of chromium from hexavalent to trivalent played a significant role in the immobilization of Cr(VI) in AAS without any additional reductants. The XRD and SEM-EDS results suggested the formation of a clear CrO4-U phase as the primary retention phase for unreduced Cr(VI). Therefore, alkali-activated slag binder is effective in the immobilization of Cr(VI)-bearing wastes.
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Affiliation(s)
- Mingtao Zhang
- College of Materials Science and Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400045, PR China.
| | - Changhui Yang
- College of Materials Science and Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400045, PR China
| | - Min Zhao
- College of Materials Science and Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400045, PR China
| | - Kai Yang
- College of Materials Science and Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400045, PR China
| | - Rui Shen
- College of Materials Science and Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400045, PR China
| | - Yujia Zheng
- College of Materials Science and Engineering, Chongqing University, 174 Shazhengjie, Shapingba, Chongqing 400045, PR China
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13
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Lu H, Wei F, Tang J, Giesy JP. Leaching of metals from cement under simulated environmental conditions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 169:319-327. [PMID: 26802528 DOI: 10.1016/j.jenvman.2015.12.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 10/27/2015] [Accepted: 12/08/2015] [Indexed: 06/05/2023]
Abstract
Leaching of metals from cement under various environmental conditions was measured to evaluate their environmental safety. A cement product containing clinker, which was produced from cement kiln co-processing of hazardous wastes, was solidified and leaching of metals was characterized using the 8-period test. Concentrations and speciation of metals in cements were determined. Effects of ambient environment and particle size on leachability of metals and mineralogical phases of cement mortars were evaluated by use of XRD and SEM. Results indicated that metals in cements were leachable in various media in descending order of: sea water, groundwater and acid rain. Cr, Ni, As, Co and V were leached by simulated sea water, while Cu, Cd, Pb, Zn, Mn, Sb and Tl were not leached in simulated sea water, groundwater or acid rain. When exposed to simulated acid rain or groundwater, amounts of Cr, Ni, As and V leached was inversely proportional to particle size of cement mortar. According to the one-dimensional diffusion equation, Cr was most leachable and the cumulative leached mass was predicted to be 9.6 mg kg(-1) after 20 years. Results of this study are useful in predicting releases of metals from cement products containing ash and clinkers cement kiln co-processing of hazardous wastes, so that they can be safely applied in the environment.
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Affiliation(s)
- Huixia Lu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Fang Wei
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Jingchun Tang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China.
| | - John P Giesy
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; School of Biological Sciences, University of Hong Kong, Hong Kong, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China
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14
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Navarro-Blasco I, Duran A, Pérez-Nicolás M, Fernández JM, Sirera R, Alvarez JI. A safer disposal of hazardous phosphate coating sludge by formation of an amorphous calcium phosphate matrix. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 159:288-300. [PMID: 26024992 DOI: 10.1016/j.jenvman.2015.05.029] [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: 02/16/2015] [Revised: 05/08/2015] [Accepted: 05/21/2015] [Indexed: 06/04/2023]
Abstract
Phosphate coating hazardous wastes originated from the automotive industry were efficiently encapsulated by an acid-base reaction between phosphates present in the sludge and calcium aluminate cement, yielding very inert and stable monolithic blocks of amorphous calcium phosphate (ACP). Two different compositions of industrial sludge were characterized and loaded in ratios ranging from 10 to 50 wt.%. Setting times and compressive strengths were recorded to establish the feasibility of this method to achieve a good handling and a safe landfilling of these samples. Short solidification periods were found and leaching tests showed an excellent retention for toxic metals (Zn, Ni, Cu, Cr and Mn) and for organic matter. Retentions over 99.9% for Zn and Mn were observed even for loadings as high as 50 wt.% of the wastes. The formation of ACP phase of low porosity and high stability accounted for the effective immobilization of the hazardous components of the wastes.
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Affiliation(s)
- I Navarro-Blasco
- MIMED Research Group, Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - A Duran
- MIMED Research Group, Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - M Pérez-Nicolás
- MIMED Research Group, Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - J M Fernández
- MIMED Research Group, Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - R Sirera
- MIMED Research Group, Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - J I Alvarez
- MIMED Research Group, Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain.
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15
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Shin HK, Park M, Chung YS, Kim HY, Jin FL, Park SJ. Antimicrobial characteristics of N-halaminated chitosan salt/cotton knit composites. J IND ENG CHEM 2014. [DOI: 10.1016/j.jiec.2013.07.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Fernández JM, Navarro-Blasco I, Duran A, Sirera R, Alvarez JI. Treatment of toxic metal aqueous solutions: encapsulation in a phosphate-calcium aluminate matrix. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2014; 140:1-13. [PMID: 24721638 DOI: 10.1016/j.jenvman.2014.01.044] [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: 11/06/2013] [Revised: 01/22/2014] [Accepted: 01/25/2014] [Indexed: 06/03/2023]
Abstract
Polyphosphate-modified calcium aluminate cement matrices were prepared by using aqueous solutions polluted with toxic metals as mixing water to obtain waste-containing solid blocks with improved management and disposal. Synthetically contaminated waters containing either Pb or Cu or Zn were incorporated into phosphoaluminate cement mortars and the effects of the metal's presence on setting time and mechanical performance were assessed. Sorption and leaching tests were also executed and both retention and release patterns were investigated. For all three metals, high uptake capacities as well as percentages of retention larger than 99.9% were measured. Both Pb and Cu were seen to be largely compatible with this cementitious matrix, rendering the obtained blocks suitable for landfilling or for building purposes. However, Zn spoilt the compressive strength values because of its reaction with hydrogen phosphate anions, hindering the development of the binding matrix.
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Affiliation(s)
- J M Fernández
- Inorganic Materials and Environment (MIMED), Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - I Navarro-Blasco
- Inorganic Materials and Environment (MIMED), Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - A Duran
- Inorganic Materials and Environment (MIMED), Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - R Sirera
- Inorganic Materials and Environment (MIMED), Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
| | - J I Alvarez
- Inorganic Materials and Environment (MIMED), Department of Chemistry and Soil Sciences, School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain.
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17
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Navarro-Blasco I, Duran A, Sirera R, Fernández JM, Alvarez JI. Solidification/stabilization of toxic metals in calcium aluminate cement matrices. JOURNAL OF HAZARDOUS MATERIALS 2013; 260:89-103. [PMID: 23747467 DOI: 10.1016/j.jhazmat.2013.04.048] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 04/24/2013] [Accepted: 04/27/2013] [Indexed: 06/02/2023]
Abstract
The ability of calcium aluminate cement (CAC) to encapsulate toxic metals (Pb, Zn and Cu) was assessed under two curing conditions. Changes in the consistency and in the setting time were found upon the addition of the nitrates of the target metals. Both Pb and Cu caused a delay in CAC hydration, while Zn accelerated the stiffening of the mortar. Compressive strengths of the metal-doped mortars, when initially cured at 60 °C/100% RH, were comparable with that of the free-metal mortar. Three different pore size distribution patterns were identified and related to the compounds identified by XRD and SEM. Sorbent capacities of CAC for the toxic metals were excellent: a total uptake was achieved for up to 3 wt.% loading of the three metals. In this way, CAC mortars were perfectly able to encapsulate the toxic metals, allowing the use of CAC for waste management as proved by the leaching tests.
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Affiliation(s)
- I Navarro-Blasco
- Inorganic Materials & Environment (MIMED), School of Sciences, University of Navarra, Irunlarrea, 1, 31008 Pamplona, Spain
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18
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Shinde RN, Pandey AK, Acharya R, Guin R, Das SK, Rajurkar NS, Pujari PK. Chitosan-transition metal ions complexes for selective arsenic(V) preconcentration. WATER RESEARCH 2013; 47:3497-3506. [PMID: 23622983 DOI: 10.1016/j.watres.2013.03.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 03/29/2013] [Accepted: 03/31/2013] [Indexed: 06/02/2023]
Abstract
Chitosan is naturally occurring bio-polymer having strong affinity towards transition metal ions. Chitosan complexed with transition metal ions takes up inorganic arsenic anions from aqueous medium. In present work, As(V) sorption in the chitosan complexed with different metal ions like Cu(II), Fe(III), La(III), Mo(VI) and Zr(IV) were studied. Sorptions of As(V) in CuS embedded chitosan, (3-aminopropyl) triethoxysilane (APTS) embedded chitosan, epichlorohydrin (ECH) crosslinked chitosan and pristine chitosan were also studied. (74)As radiotracer was prepared specifically for As(V) sorption studies by irradiation of natural germanium target with 18 MeV proton beam. The sorption studies indicated that Fe(III) and La(III) complexed with chitosan sorbed 95 ± 2% As(V) from aqueous samples in the pH range of 3-9. However, Fe(III)-chitosan showed better sorption efficiency (91 ± 2%) for As(V) from seawater than La(III)-chitosan (80 ± 2%). Therefore, Fe(III)-chitosan was selected to prepare the self-supported membrane and poly(propylene) fibrous matrix supported sorbent. The experimental As(V) sorption capacities of the fibrous and self-supported Fe(III)-chitosan sorbents were found to be 51 and 109 mg g(-1), respectively. These materials were characterized by XRD, SEM and EDXRF, and used for preconcentration of As(V) in aqueous media like tap water, ground water and seawater. To quantify the As(V) preconcentrated in Fe(III)-chitosan, the samples were subjected to instrumental neutron activation analysis (INAA) using reactor neutrons. As(V) separations were carried out using a two compartments permeation cell for the self-supported membrane and flow cell using the fibrous sorbent. The total preconcentration of arsenic content was also explored by converting As(III) to As(V).
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Affiliation(s)
- Rakesh N Shinde
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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19
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Bujalowski PJ, Oberhauser AF. Tracking unfolding and refolding reactions of single proteins using atomic force microscopy methods. Methods 2013; 60:151-60. [PMID: 23523554 DOI: 10.1016/j.ymeth.2013.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/07/2013] [Accepted: 03/11/2013] [Indexed: 11/26/2022] Open
Abstract
During the last two decades single-molecule manipulation techniques such as atomic force microscopy (AFM) has risen to prominence through their unique capacity to provide fundamental information on the structure and function of biomolecules. Here we describe the use of single-molecule AFM to track protein unfolding and refolding pathways, enzymatic catalysis and the effects of osmolytes and chaperones on protein stability and folding. We will outline the principles of operation for two different AFM pulling techniques: length clamp and force-clamp and discuss prominent applications. We provide protocols for the construction of polyproteins which are amenable for AFM experiments, the preparation of different coverslips, choice and calibration of AFM cantilevers. We also discuss the selection criteria for AFM recordings, the calibration of AFM cantilevers, protein sample preparations and analysis of the obtained data.
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Affiliation(s)
- Paul J Bujalowski
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, TX 77555, USA
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