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Du Y, Shi T, Guo S, Li H, Qin Y, Wang Y, He C, Wei Y. Unraveling the intrinsic mechanism behind the retention of arsenic in the co-gasification of coal and sewage sludge: Focus on the role of Ca and Fe compounds. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134211. [PMID: 38598878 DOI: 10.1016/j.jhazmat.2024.134211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/27/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Minimizing the emission of arsenic (As) is one of the urgent problems during co-gasification of Shenmu coal (SM) and sewage sludge (SS). The intrinsic mechanism of As retention was obtained by analyzing the effect of different SM addition ratios on the As form transformation during co-gasification at 1000 °C under CO2 atmosphere. The results showed that the addition of SM effectively promoted the enrichment of As in the co-gasified residues. Especially, the best As retention rate of 65.71% was achieved with the 70 wt% addition ratio of SM. The addition of SM promoted the adsorption and chemical oxidation of As(III) to the less toxic As(V) through the coupling of Ca and Fe compounds in the co-gasified residues. XRD and XPS results indicated that Fe2O3 adsorbed As2O3(g) after partial conversion to Fe3O4 by the Boudouard reaction, while part of As2O3 was oxidized to As2O5 by lattice oxygen. Finally, the generated As2O5 was successively trapped by CaO and Fe2O3 to form stable Ca3(AsO4)2 and FeAsO4. HRTEM and TEM analysis comprehensively proved that As(III) was stabilized by the lattice cage of CaAl2Si2O8. In conclusion, the co-oxidation of Ca and Fe compounds and lattice stabilization simultaneously played a crucial role in the retention of As2O3(g) during co-gasification.
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Affiliation(s)
- Yujia Du
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China
| | - Tingrui Shi
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China
| | - Shugang Guo
- Shanxi Provincial Center for Disease Control and Prevention, 8 Xiaonanguan Street, Taiyuan 030012, PR China
| | - Hugang Li
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China; Laboratory of Ecology-based Solutions, College of Ecology, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China
| | - Yuhong Qin
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China.
| | - Yuefeng Wang
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China
| | - Chong He
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China
| | - Yuexing Wei
- College of Environmental Science and Engineering, Taiyuan University of Technology, No. 79 Yingze West Street, Taiyuan 030024, PR China
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Yin K, Ahamed A, Lisak G. Environmental perspectives of recycling various combustion ashes in cement production - A review. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 78:401-416. [PMID: 32559927 DOI: 10.1016/j.wasman.2018.06.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/02/2018] [Accepted: 06/06/2018] [Indexed: 05/10/2023]
Abstract
Recycling different types of ashes for cement production has gained increasing attentions worldwide in a bid to close the waste loop. It minimizes waste landfilling and meanwhile produces useful secondary materials with reduced costs. Ascribed to the presence of elevated metal concentrations, however, it also receives negative inclination for their reuse. Herein, recycling various combustion ashes, such as municipal solid waste incineration fly ashes (MSWI FA), municipal solid waste incineration bottom ashes (MSWI BA), coal fly ashes (CFA), coal bottom ashes (CBA), blast furnace slags (BFS), biomass ashes (BIOA), sewage sludge ashes (SSA) and different co-combustion ashes (CCA), were comprehensively reviewed, from environmental perspectives combined with statistical data analysis (e.g. bulk components, trace metals, leaching potential, and etc.), to quantitatively explore their feasibility during cement production. It was unveiled that pozzolanic contents were predominant which highly fluctuated in their composition based on the ash type, limiting the replacement at maximum of 5-10 wt%. Considering total metal criteria, heavy metal contents posed challenges as secondary raw materials for blended cements. However, in consideration of metal leaching criteria, exothermic pozzolanic reactions in the second phase of blended cement would sufficiently alleviate their leaching potential, ensuring the environmental feasibility. Apart from the above, treatment costs have to be evaluated in nexus of multiple factors, whereas government policies play significant roles in valorization of recycling ashes. From sustainability perspective, life cycle assessment promises the overall strategy on ash utilization in cement industry.
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Affiliation(s)
- Ke Yin
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore.
| | - Ashiq Ahamed
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore
| | - Grzegorz Lisak
- Residue and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Singapore; Department of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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3
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Hu H, Shi M, Yang Y, Liu H, Xu M, Shen J, Yao H. Further Insight into the Formation and Oxidation of CaCr 2O 4 during Solid Fuel Combustion. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2385-2391. [PMID: 29390188 DOI: 10.1021/acs.est.7b05538] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The control of toxic chromate (Cr6+) formation is still a significant challenge in solid fuel combustion. In particular, the mechanism of chromium transformation from Cr3+ to chromate or other unoxidized forms remains unclear. The present study confirms the formation of a significant unoxidized Cr-containing compound CaCr2O4(Cr3+) during solid fuel combustion. Experiments were conducted, for the first time, to clarify the mechanism of CaCr2O4 oxidation, which is quite different from Cr2O3 oxidation. The findings demonstrate that CaCr2O4 was formed at temperatures above 1200 K, through rapid decomposition of CaCrO4 or slow and direct interaction between CaO and Cr2O3. Compared to Cr2O3, CaCr2O4 could be oxidized at lower temperatures under the influence of free CaO. In the absence of free CaO, the oxidation of CaCr2O4 was minimal; however, in the presence of CaSO4, calcium in the form of CaCr2O4 participated in the oxidation of CaCr2O4. Thus, chromium in the form of CaCr2O4 was more likely to be oxidized when CaCr2O4-containing fly ash was reheated. Fortunately, CaCr2O4 showed slight basicity on the surface, allowing it to react with acidic gases. Accordingly, measures were proposed to suppress the oxidation of CaCr2O4 by stimulating the reactions between CaCr2O4 and acidic substances, like SO2 and Si/Al-compounds. These compounds competed with chromium at high temperatures to react with calcium in the fly ash and in CaCr2O4. As a result, the unoxidized chromium was transformed into highly stable Cr2O3 or Ca3Cr2 (SiO4)3.
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Affiliation(s)
- Hongyun Hu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Mengya Shi
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Yuhan Yang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Huan Liu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
- Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Mian Xu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Junhao Shen
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
| | - Hong Yao
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
- Department of New Energy Science and Engineering, School of Energy and Power Engineering, Huazhong University of Science and Technology , Wuhan 430074, P. R. China
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Mishima I, Hama M, Tabata Y, Nakajima J. Improvement of phosphorus removal by calcium addition in the iron electrocoagulation process. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2017; 76:920-927. [PMID: 28799938 DOI: 10.2166/wst.2017.256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Small-scale wastewater treatment plants (SWTPs) are widely used as decentralized wastewater treatment systems in sparsely populated areas of Japan. Iron electrolysis, an electrocoagulation technology, is installed in these SWTPs for phosphorus removal. Phosphorus can be removed via the formation of an insoluble compound containing phosphate and iron, such as FePO4; however, it was necessary to determine the conditions under which phosphorus can be effectively and stably removed in actual SWTPs. According to previous studies using iron compounds, improved phosphorus removal was obtained by Ca addition. It is therefore thought that calcium addition may also be effective in improving the phosphorus removal during iron electrolysis in SWTPs. It is also important to determine the chemical state of iron to understand the phosphorus removal mechanism during iron electrolysis. In this study, laboratory-scale batch experiments with the iron electrolysis method were conducted to investigate the effect of phosphorus removal using treated wastewater from actual SWTPs without or with Ca addition. The results indicated that the addition of Ca improved the phosphorus removal performance. Furthermore, phosphorus removal was inhibited in the presence of high dissolved organic carbon (DOC). The X-ray absorption fine structure measurements of the produced particulates in the experiments showed no substantial change in the chemical state of iron without or with Ca addition. The statistical analyses revealed the range of improving or inhibiting effects on phosphorus removal due to the Ca and DOC. Thus, the results of this study provided useful information pertaining to the influence of coexisting substances on phosphorus removal and the chemical state of iron in the produced particulates.
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Affiliation(s)
- I Mishima
- Water Environment Group, Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo 347-0115, Japan E-mail:
| | - M Hama
- 1st Development Department, Fuji Clean Co., Ltd, 4-2-21 Neura, Miyoshi, Aichi, Japan
| | - Y Tabata
- 2nd Development Department, Fuji Clean Co., Ltd, Yamahana 33, Yamayashiki, Chiryu 472-0022, Japan
| | - J Nakajima
- Master's Program in Environmental Engineering, Vietnam Japan University, Luu Huu Phuoc, My Dinh 1, Nam Tu Liem, Hanoi, Vietnam
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Gorazda K, Tarko B, Wzorek Z, Kominko H, Nowak AK, Kulczycka J, Henclik A, Smol M. Fertilisers production from ashes after sewage sludge combustion - A strategy towards sustainable development. ENVIRONMENTAL RESEARCH 2017; 154:171-180. [PMID: 28086102 DOI: 10.1016/j.envres.2017.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/24/2016] [Accepted: 01/03/2017] [Indexed: 05/26/2023]
Abstract
Sustainable development and circular economy rules force the global fertilizer industry to develop new phosphorous recovery methods from alternative sources. In this paper a phosphorus recovery technology from Polish industrial Sewage Sludge Ashes was investigated (PolFerAsh - Polish Fertilizers form Ash). A wet method with the use of mineral acid and neutralization was proposed. Detailed characteristic of SSA from largest mono-combustion plans were given and compared to raw materials used on the market. The technological factors associated with such materials were discussed. The composition of the extracts was compared to typical industrial phosphoric acid and standard values characterizing suspension fertilizers. The most favorable conditions for selective precipitation of phosphorus compounds were revealed. The fertilizers obtained also meet EU regulations in the case of the newly discussed Cd content. The process was scaled up and a flow mass diagram was defined.
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Affiliation(s)
- Katarzyna Gorazda
- Institute of Inorganic Chemistry and Technology, Cracow University of Technology, Ul. Warszawska 24, Kraków, Poland.
| | - Barbara Tarko
- Institute of Inorganic Chemistry and Technology, Cracow University of Technology, Ul. Warszawska 24, Kraków, Poland.
| | - Zbigniew Wzorek
- Institute of Inorganic Chemistry and Technology, Cracow University of Technology, Ul. Warszawska 24, Kraków, Poland.
| | - Halyna Kominko
- Institute of Inorganic Chemistry and Technology, Cracow University of Technology, Ul. Warszawska 24, Kraków, Poland.
| | - Anna K Nowak
- Institute of Inorganic Chemistry and Technology, Cracow University of Technology, Ul. Warszawska 24, Kraków, Poland.
| | - Joanna Kulczycka
- Cracow University of Science and Technology, Ul. Gramatyka 10, Kraków, Poland.
| | - Anna Henclik
- The Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Ul. Wybickiego 7, Kraków, Poland.
| | - Marzena Smol
- The Mineral and Energy Economy Research Institute of the Polish Academy of Sciences, Ul. Wybickiego 7, Kraków, Poland
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6
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Vogel C, Krüger O, Herzel H, Amidani L, Adam C. Chemical state of mercury and selenium in sewage sludge ash based P-fertilizers. JOURNAL OF HAZARDOUS MATERIALS 2016; 313:179-184. [PMID: 27060867 DOI: 10.1016/j.jhazmat.2016.03.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/18/2016] [Accepted: 03/27/2016] [Indexed: 06/05/2023]
Abstract
Phosphorus-fertilizers from secondary resources such as sewage sludge ash (SSA) will become more important in the future as they could substitute conventional fertilizers based on the nonrenewable resource phosphate rock. Thermochemical approaches were developed which remove heavy metals from SSA prior to its fertilizer application on farmlands. We analyzed the chemical state of mercury and selenium in SSA before and after thermochemical treatment under different conditions for P-fertilizer production by X-ray absorption near edge structure (XANES) spectroscopy. In some incineration plants the mercury loaded carbon adsorber from off-gas cleaning was collected together with the SSA for waste disposal. SSAs from those plants contained mercury mainly bound to carbon/organic material. The other SSAs contained inorganic mercury compounds which are most probably stabilized in the SSA matrix and were thus not evaporated during incineration. During thermochemical treatment, carbon-bound mercury was removed quantitatively. In contrast, a certain immobile fraction of inorganic mercury compounds remained in thermochemically treated SSA, which were not clearly identified. HgSe might be one of the inorganic compounds, which is supported by results of Se K-edge XANES spectroscopy. Furthermore, the chemical state of selenium in the SSAs was very sensitive to the conditions of the thermochemical treatment.
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Affiliation(s)
- Christian Vogel
- Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
| | - Oliver Krüger
- Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Hannes Herzel
- Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
| | - Lucia Amidani
- ESRF-The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Christian Adam
- Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
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7
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Oshita K, Kawaguchi K, Takaoka M, Matsukawa K, Fujimori T, Fujiwara T. Emission and control of N 2O and composition of ash derived from cattle manure combustion using a pilot-scale fluidized bed incinerator. ENVIRONMENTAL TECHNOLOGY 2016; 37:439-445. [PMID: 26243142 DOI: 10.1080/09593330.2015.1077190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This study investigates the emission of nitrous oxide (N2O) and discusses the reduction of N2O emissions during the 24-h combustion of cattle manure using a pilot-scale fluidized bed incinerator under various experimental conditions. The results of these experiments were then validated against previously reported data. In addition, the characteristics of cattle manure incineration ash and their changes under different combustion conditions were estimated. In incineration experiments with composted cattle manure, N2O concentrations using multi-stage combustion were 75% lower than the concentrations resulting from normal combustion without additional auxiliary fuel, since N2O could be decomposed in the high-temperature zone formed by the inlet of the secondary combustion air. The N2O emission factor under normal combustion conditions (800°C) was 6.0% g-N2O-N/g-N. This result is similar to the values found in previous studies at the same temperature. The N2O emission factor was decreased to 1.6% g-N2O-N/g-N using a multi-stage combustion procedure. The current Japanese N2O emission factor of 0.1% g-N2O-N/g-N is an underestimate for some conditions and should be uniquely specified for each condition. Finally, cattle manure ash contains ample fertilizer elements, little Fe, Al and Zn, but abundant Cl. Therefore if Cl could be removed by some kind of pretreatment, cattle manure ash could be used as a favourable fertilizer.
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Affiliation(s)
- Kazuyuki Oshita
- a Graduate School of Global Environmental Studies , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
- b Department of Environmental Engineering, Graduate School of Engineering , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
- c Department of Chemical Engineering , KU Leuven , Jan De Nayerlaan 5, 2860, Sint-Katelijne-Waver , Belgium
- d Japan Science and Technology Agency, CREST , Saitama , Japan
| | - Koji Kawaguchi
- b Department of Environmental Engineering, Graduate School of Engineering , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
- d Japan Science and Technology Agency, CREST , Saitama , Japan
- e Taiyo Chikuro Industries, Co., Ltd ., 6-21, Higashi-kouen, Hakata-ku, Fukuoka 812-0045 , Japan
| | - Masaki Takaoka
- a Graduate School of Global Environmental Studies , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
- b Department of Environmental Engineering, Graduate School of Engineering , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
- d Japan Science and Technology Agency, CREST , Saitama , Japan
| | - Kazutsugu Matsukawa
- d Japan Science and Technology Agency, CREST , Saitama , Japan
- f Multidisciplinary Science Cluster , Kochi University , 200, Monobe-otsu, Nankoku 783-8502 , Japan
| | - Takashi Fujimori
- a Graduate School of Global Environmental Studies , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
- b Department of Environmental Engineering, Graduate School of Engineering , Kyoto University , Cluster C, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540 , Japan
| | - Taku Fujiwara
- d Japan Science and Technology Agency, CREST , Saitama , Japan
- g Natural Sciences Cluster, Agriculture Unit , Kochi University , 200, Monobe-otsu, Nankoku 783-8502 , Japan
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Shiota K, Takaoka M, Fujimori T, Oshita K, Terada Y. Cesium Speciation in Dust from Municipal Solid Waste and Sewage Sludge Incineration by Synchrotron Radiation Micro-X-ray Analysis. Anal Chem 2015; 87:11249-54. [DOI: 10.1021/acs.analchem.5b03298] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kenji Shiota
- Department
of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku,
Kyoto 615-8540, Japan
| | - Masaki Takaoka
- Department
of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku,
Kyoto 615-8540, Japan
- Graduate
School of Global Environmental Studies, Kyoto University, Cluster
C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takashi Fujimori
- Department
of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku,
Kyoto 615-8540, Japan
- Graduate
School of Global Environmental Studies, Kyoto University, Cluster
C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Kazuyuki Oshita
- Department
of Environmental Engineering, Graduate School of Engineering, Kyoto University, Cluster C, Kyoto Daigaku-Katsura, Nishikyo-ku,
Kyoto 615-8540, Japan
- Graduate
School of Global Environmental Studies, Kyoto University, Cluster
C, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yasuko Terada
- Japan
Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
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9
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Vogel C, Adam C, Kappen P, Schiller T, Lipiec E, McNaughton D. Chemical state of chromium in sewage sludge ash based phosphorus-fertilisers. CHEMOSPHERE 2014; 103:250-255. [PMID: 24373226 DOI: 10.1016/j.chemosphere.2013.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 11/18/2013] [Accepted: 12/02/2013] [Indexed: 06/03/2023]
Abstract
Sewage sludge ash (SSA) based P-fertilisers were produced by thermochemical treatment of SSA with Cl-donors at approximately 1000°C. During this thermochemical process heavy metals are separated as heavy metal chlorides via the gas phase. Chromium cannot be separated under normal conditions. The risk of the development of toxic Cr(VI) during the thermochemical process was investigated. X-ray Absorption Spectroscopy measurements showed that SSA and thermochemically treated SSA with CaCl2, MgCl2 and NaCl contain Cr(III) compounds only. In contrast, treating SSA with elevated quantities of Na2CO3, to enhance the plant-availability of the phosphate phases of the fertiliser, developed approximately 10-15% Cr(VI). Furthermore, Raman microspectroscopy showed that using Mg-carbonate reduces the risk of a Cr(VI) development during thermochemical treatment. Additionally, leaching tests showed that only a Cr-water solubility>10% is an indicator for Cr(VI) in SSA based P-fertilisers.
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Affiliation(s)
- Christian Vogel
- School of Chemistry, Monash University, Wellington Road, Clayton 3800, Victoria, Australia; BAM Federal Institute for Materials Research and Testing, Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Unter den Eichen 87, D-12205 Berlin, Germany.
| | - Christian Adam
- BAM Federal Institute for Materials Research and Testing, Division 4.4 Thermochemical Residues Treatment and Resource Recovery, Unter den Eichen 87, D-12205 Berlin, Germany
| | - Peter Kappen
- Australian Synchrotron, 800 Blackburn Road, Clayton 3168, Victoria, Australia; Department of Physics, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Tara Schiller
- School of Chemistry, Monash University, Wellington Road, Clayton 3800, Victoria, Australia; Department of Materials Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia
| | - Ewelina Lipiec
- School of Chemistry, Monash University, Wellington Road, Clayton 3800, Victoria, Australia; The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, E. Radzikowskiego 152, 31-342 Kraków, Poland
| | - Don McNaughton
- School of Chemistry, Monash University, Wellington Road, Clayton 3800, Victoria, Australia
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Oki M, Morimoto S, Muramatsu M, Yoshiki M, Takenaka M. Application of X-ray absorption fine structure method for the quantitative analysis of hexavalent chromium in chromate conversion coating and plastic. APPLIED SPECTROSCOPY 2014; 68:406-412. [PMID: 24694696 DOI: 10.1366/13-07014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The X-ray absorption fine structure method was applied for the quantitative analysis of hexavalent Cr in electronic products. The pre-edge peak intensity of the Cr K-edge increased according to the hexavalent Cr amount, and the hexavalent Cr ratio was calculated quantitatively by using the intensity. By combining with inductively coupled plasma atomic emission spectroscopy measurement results that gave the total Cr amount, the absolute amount of hexavalent Cr in chromate conversion coating and plastic samples could be evaluated. The results obtained by this method were in good agreement with those obtained by the chemical analysis method. This method can be successfully applied for the determination of hexavalent Cr amount in electronic products such as chromate conversion coating and plastic.
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Affiliation(s)
- Mitsuhiro Oki
- Corporate Research and Development Center, Toshiba Corporation, 1 Komukai Toshiba-cho, Saiwai, Kawasaki 212-8582, Japan
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Jiao F, Wijaya N, Zhang L, Ninomiya Y, Hocking R. Synchrotron-based XANES speciation of chromium in the oxy-fuel fly ash collected from lab-scale drop-tube furnace. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:6640-6646. [PMID: 21668013 DOI: 10.1021/es200545e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Speciation of chromium (Cr) in the fly ash collected from oxy-firing of Victorian brown coal has been reported for the first time to address the potential formation of toxic Cr(VI) and the variation of the quantities of Cr(III)-bearing species with flue gas composition. Synchrotron-based X-ray absorption near-edge structure (XANES) was employed for Cr speciation. Apart from a pure O(2)/CO(2) mixture (27/73, v/v) versus air, the O(2)/CO(2) mixtures doped with SO(2), HCl, and steam individually or together to simulate real flue gas have also been tested. Under all of the conditions tested here, the fractions of Cr(VI) in the fly ashes are insignificant, constituting no more than 5% of the total Cr. The test of Cr-doped brown coal in pyrolysis further confirmed that the Cr(VI) formation preferentially occurred through a local oxidation of Cr(III) at the oxygen-containing functions sites within coal matrix, rather than through an oxidation by external bulk O(2). This reaction is also highly temperature-dependent and slower than the interaction between Cr(III) and other metals such as iron oxide. Increasing temperature to 1000 °C inhibited the oxidation of Cr(IIII) to Cr(VI). Shifting the combustion gas from air to O(2)/CO(2) exerted little effect on the Cr(VI) formation. Instead, the formation of iron chromite (FeCr(2)O(4)) was facilitated in O(2)/CO(2), probably due to a strong reducing microenvironment formed by the CO(2) gasification reaction within the char matrix. The accumulation of HCl in flue gas favored the vaporization of chromium as gaseous chloride/oxychloride, as expected. The coexistence of SO(2) inhibited this phenomenon by promoting the formation of sulfate. The presence of steam was even beneficial for the inhibition of water-soluble Cr sulfate through stabilizing the majority of Cr into alumino-silicate which is in the slagging phase.
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Affiliation(s)
- Facun Jiao
- Department of Chemical Engineering, Monash University, Clayton, Victoria, Australia
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