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Insight into pyrolysis of hydrophobic silica aerogels: kinetics, reaction mechanism and effect on the aerogels. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.10.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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2
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Synergistic effect of hydration and carbonation of ladle furnace aslag on cementitious substances. Sci Rep 2022; 12:14526. [PMID: 36008467 PMCID: PMC9411115 DOI: 10.1038/s41598-022-18215-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 08/08/2022] [Indexed: 11/15/2022] Open
Abstract
Ladle furnace slag (LFS) can undergo hydration and carbonation reactions as cement. This article explores the effect of LFS hydration and carbonation reactions on cementitious substances at different temperatures and different LFS particle sizes, determining the effect of these varying conditions on the microstructure and formation mechanism of cementitious substances. The results show that in the early stages, C2S and C3S undergo hydration to generate C–S–H gel, which then undergoes decalcification and condensation to generate CaCO3 and Ca-deficient C–S–H gel; the hydration reaction and carbonation reaction promote and influence each other. The increase in temperature was found to hinder the formation of CaCO3 from Ca2+ and CO32−, thus reducing the efficiency of hydration carbonation. The increase in particle size was not conducive to the leaching of C2S and C3S to the surface of the reaction phase, which in turn reduced the degree of decalcification and polymerization of the C–S–H gel in the carbonation phase. It was concluded that the optimum LFS hydration and carbonation reactions were achieved at 20 °C and with a LFS particle sizes < 38 μm.
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Venkatraman SK, Vijayakumar N, Bal DK, Mishra A, Gupta B, Mishra V, Wysokowski M, Koppala S, Swamiappan S. Degradation of environmentally harmful textile dye rhodamine B using silicate ceramic photocatalysts. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109674] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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The Importance of Precursors and Modification Groups of Aerogels in CO 2 Capture. Molecules 2021; 26:molecules26165023. [PMID: 34443610 PMCID: PMC8399094 DOI: 10.3390/molecules26165023] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/30/2021] [Accepted: 08/11/2021] [Indexed: 11/16/2022] Open
Abstract
The rapid growth of CO2 emissions in the atmosphere has attracted great attention due to the influence of the greenhouse effect. Aerogels' application for capturing CO2 is quite promising owing to their numerous advantages, such as high porosity (~95%); these are predominantly mesoporous (20-50 nm) materials with very high surface area (>800 m2∙g-1). To increase the CO2 level of aerogels' uptake capacity and selectivity, active materials have been investigated, such as potassium carbonate, K2CO3, amines, and ionic-liquid amino-acid moieties loaded onto the surface of aerogels. The flexibility of the composition and surface chemistry of aerogels can be modified intentionally-indeed, manipulated-for CO2 capture. Up to now, most research has focused mainly on the synthesis of amine-modified silica aerogels and the evaluation of their CO2-sorption properties. However, there is no comprehensive study focusing on the effect of different types of aerogels and modification groups on the adsorption of CO2. In this review, we present, in broad terms, the use of different precursors, as well as modification of synthesis parameters. The present review aims to consider which kind of precursors and modification groups can serve as potentially attractive molecular-design characteristics in promising materials for capturing CO2.
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Ragipani R, Bhattacharya S, Suresh AK. A review on steel slag valorisation via mineral carbonation. REACT CHEM ENG 2021. [DOI: 10.1039/d1re00035g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alkaline slags, a waste product of steel industry, provide an opportunity for carbon sequestration and creation of value at the same time. This requires an understanding of the mechanisms of leaching and carbonation.
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Affiliation(s)
- Raghavendra Ragipani
- IITB-Monash Research Academy
- Indian Institute of Technology Bombay
- Mumbai
- India
- Department of Chemical Engineering
| | | | - Akkihebbal K. Suresh
- Department of Chemical Engineering
- Indian Institute of Technology Bombay
- Mumbai
- India
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Tang H, Li C, Duan Y, Zhu C, Cai L. Combined experimental and theoretical studies on adsorption mechanisms of gaseous mercury(II) by calcium-based sorbents: The effect of unsaturated oxygen sites. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 656:937-945. [PMID: 30625679 DOI: 10.1016/j.scitotenv.2018.11.460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/24/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
Accurate mercury speciation measurements are critical for developing methods for mercury removal from flue gas, but the lack of reliable adsorbents has made Hg2+ selective retention challenging. Calcium oxide (CaO) loaded on porous support is promising for HgCl2 selective adsorption because of its porosity and alkaline nature. The main hypothesis investigated in this paper is if the capacity of CaO sorbent for HgCl2 selective adsorption is attributed to its basic sites, then this will be drastically impacted by the calcium precursors. We synthesized a suite of CaO/SiO2 sorbents from different precursors, including hydrated calcium oxide (CaO-HS), calcium nitrate tetrahydrate (CaO-NS), and calcium acetate monohydrate (CaO-AcS), to investigate their performance on HgCl2 selective adsorption in a fixed-bed reactor. Compared with CaO-HS and CaO-NS, CaO-AcS was demonstrated to have the strongest affinity for HgCl2 and almost complete breakthrough for Hg0. Advanced porosity and surface basicity of CaO-AcS were confirmed by characterization analysis. CaO (001) and CaO (011) facet as well as surface defects that have different unsaturated O sites were observed using the high resolution transmission electron microscope (HRTEM). Combined theoretical and experimental methods were used to study the interaction mechanisms between HgCl2 and basic sites on CaO-AcS surfaces. Density functional theory (DFT) calculations indicated all CaO surfaces weakly interact with Hg0, while four robust bonding states of HgCl2 were predicted on different basic sites with the intensity in increasing order: Monodentate < Tridendate < Bidentate < Bridging. This was consistent with HgCl2-TPD experiments that demonstrated that the four HgCl2 adsorption configurations on CaO-AcS were attributed to different unsaturated O sites. The findings in this work highlight the application potential of CaO-AcS for gaseous Hg2+ sampling and measurement from coal-fired flue gas.
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Affiliation(s)
- Hongjian Tang
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
| | - Chunfeng Li
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yufeng Duan
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China.
| | - Chun Zhu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
| | - Liang Cai
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
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Romero-Hermida I, Santos A, Pérez-López R, García-Tenorio R, Esquivias L, Morales-Flórez V. New method for carbon dioxide mineralization based on phosphogypsum and aluminium-rich industrial wastes resulting in valuable carbonated by-products. J CO2 UTIL 2017. [DOI: 10.1016/j.jcou.2017.01.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Li Z, Cheng X, Shi L, He S, Gong L, Li C, Zhang H. Flammability and oxidation kinetics of hydrophobic silica aerogels. JOURNAL OF HAZARDOUS MATERIALS 2016; 320:350-358. [PMID: 27566928 DOI: 10.1016/j.jhazmat.2016.07.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 07/19/2016] [Accepted: 07/22/2016] [Indexed: 06/06/2023]
Abstract
Silica aerogels (SAs) present great application prospects especially on thermal insulation, but their flammability is usually ignored. A combined study on the combustion behaviors and oxidation kinetics of hydrophobic silica aerogels prepared by ambient pressure drying (SA-apd) and supercritical drying (SA-sd) was performed by employing cone calorimeter and thermal analysis. The whole combustion process for SAs could be divided into three stages in which a fire propagation phenomenon was observed with the radial propagation velocity of 6.6-8.3cms-1. Current investigations forcefully demonstrated that hydrophobic SAs were combustible and easy to flashover when exposed to a heat flux higher than 25kWm-2. Compared between the two SAs, the SA-sd owned a less fire risk with presenting a less fire hazard and a lower smoke toxicity than those of SA-apd. The oxidation kinetics by Ozawa-Flynn-Wall method revealed that SA-sd had larger apparent activation energies than those of SA-apd which conformed to the thermal stability analysis by TG-DSC. Furthermore, a two-step combustion mechanism was proposed to explain the combustion behaviors of SAs.
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Affiliation(s)
- Zhi Li
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China
| | - Xudong Cheng
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China.
| | - Long Shi
- Civil and Infrastructure Engineering Discipline, School of Engineering, RMIT University, GPO Box 2476, Melbourne VIC 3001, Australia
| | - Song He
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China
| | - Lunlun Gong
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China
| | - Congcong Li
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China
| | - Heping Zhang
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230027, P. R. China.
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Santín C, Doerr SH, Otero XL, Chafer CJ. Quantity, composition and water contamination potential of ash produced under different wildfire severities. ENVIRONMENTAL RESEARCH 2015; 142:297-308. [PMID: 26186138 DOI: 10.1016/j.envres.2015.06.041] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 06/27/2015] [Accepted: 06/29/2015] [Indexed: 06/04/2023]
Abstract
Wildfires frequently threaten water quality through the transfer of eroded ash and soil into rivers and reservoirs. The ability to anticipate risks for water resources from wildfires is fundamental for implementing effective fire preparedness plans and post-fire mitigation measures. Here we present a new approach that allows quantifying the amount and characteristics of ash generated under different wildfire severities and its respective water contamination potential. This approach is applied to a wildfire in an Australian dry sclerophyll eucalypt forest, but can be adapted for use in other environments. The Balmoral fire of October 2013 affected 12,694 ha of Sydney's forested water supply catchment. It produced substantial ash loads that increased with fire severity, with 6, 16 and 34 Mg ha(-1) found in areas affected by low, high and extreme fire severity, respectively. Ash bulk density was also positively related to fire severity. The increase with fire severity in the total load and bulk density of the ash generated is mainly attributed to a combination of associated increases in (i) total amount of fuel affected by fire and (ii) contribution of charred mineral soil to the ash layer. Total concentrations of pollutants and nutrients in ash were mostly unrelated to fire severity and relatively low compared to values reported for wildfire ash in other environments (e.g. 4.0-7.3mg As kg(-1); 2.3-4.1 B mg kg(-1); 136-154 P mg kg(-1)). Solubility of the elements analysed was also low, less than 10% of the total concentration for all elements except for B (6-14%) and Na (30-50%). This could be related to a partial loss of soluble components by leaching and/or wind erosion before the ash sampling (10 weeks after the fire and before major ash mobilisation by water erosion). Even with their relatively low concentrations of potential pollutants, the substantial total ash loads found here represent a water contamination risk if transported into the hydrological network during severe erosion events. For example, up to 4 Mg of ash-derived P could be delivered into a single water supply reservoir.
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Affiliation(s)
- Cristina Santín
- Geography Department, Swansea University, Singleton Park, Swansea SA28PP, United Kingdom.
| | - Stefan H Doerr
- Geography Department, Swansea University, Singleton Park, Swansea SA28PP, United Kingdom.
| | - Xosé L Otero
- Department of Edaphology and Agricultural Chemistry, University of Santiago de Compostela, Santiago de Compostela 15782, Spain.
| | - Chris J Chafer
- Water NSW, 2-6 Station Street, Penrith, NSW 2750, Australia.
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Morales-Flórez V, Santos A, López A, Moriña I, Esquivias L. Calcium silicates synthesised from industrial residues with the ability for CO2 sequestration. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2014; 32:1178-1185. [PMID: 25012303 DOI: 10.1177/0734242x14542148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This work explored several synthesis routes to obtain calcium silicates from different calcium-rich and silica-rich industrial residues. Larnite, wollastonite and calcium silicate chloride were successfully synthesised with moderate heat treatments below standard temperatures. These procedures help to not only conserve natural resources, but also to reduce the energy requirements and CO2 emissions. In addition, these silicates have been successfully tested as carbon dioxide sequesters, to enhance the viability of CO2 mineral sequestration technologies using calcium-rich industrial by-products as sequestration agents. Two different carbon sequestration experiments were performed under ambient conditions. Static experiments revealed carbonation efficiencies close to 100% and real-time resolved experiments characterised the dynamic behaviour and ability of these samples to reduce the CO2 concentration within a mixture of gases. The CO2 concentration was reduced up to 70%, with a carbon fixation dynamic ratio of 3.2 mg CO2 per g of sequestration agent and minute. Our results confirm the suitability of the proposed synthesis routes to synthesise different calcium silicates recycling industrial residues, being therefore energetically more efficient and environmentally friendly procedures for the cement industry.
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Affiliation(s)
- Victor Morales-Flórez
- Departamento de Física de la Materia Condensada, Universidad de Sevilla, Seville, Spain Instituto de Ciencia de Materiales de Sevilla (CSIC-US), Seville, Spain
| | - Alberto Santos
- Departamento de Ciencias de la Tierra, Universidad de Cádiz, Puerto Real, Spain
| | - Antonio López
- Instalaciones INABENSA SA, CIL Torrecuéllar, Seville, Spain
| | - Isabel Moriña
- Instalaciones INABENSA SA, CIL Torrecuéllar, Seville, Spain
| | - Luis Esquivias
- Departamento de Física de la Materia Condensada, Universidad de Sevilla, Seville, Spain Instituto de Ciencia de Materiales de Sevilla (CSIC-US), Seville, Spain
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11
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Technological Proposals for Recycling Industrial Wastes for Environmental Applications. MINERALS 2014. [DOI: 10.3390/min4030746] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Si C, Ma Y, Lin C. Red mud as a carbon sink: variability, affecting factors and environmental significance. JOURNAL OF HAZARDOUS MATERIALS 2013; 244-245:54-59. [PMID: 23246940 DOI: 10.1016/j.jhazmat.2012.11.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/09/2012] [Accepted: 11/10/2012] [Indexed: 06/01/2023]
Abstract
The capacity of red mud to sequester CO(2) varied markedly due to differences in bauxite type, processing and disposal methods. Calcium carbonates were the dominant mineral phases responsible for the carbon sequestration in the investigated red mud types. The carbon sequestration capacity of red mud was not fully exploited due to shortages of soluble divalent cations for formation of stable carbonate minerals. Titanate and silicate ions were the two major oxyanions that appeared to strongly compete with carbonate ions for the available soluble Ca. Supply of additional soluble Ca and Mg could be a viable pathway for maximizing carbon sequestration in red mud and simultaneously reducing the causticity of red mud. It is roughly estimated that over 100 million tonnes of CO(2) have been unintentionally sequestered in red mud around the world to date through the natural weathering of historically produced red mud. Based on the current production rate of red mud, it is likely that some 6 million tonnes of CO(2) will be sequestered annually through atmospheric carbonation. If appropriate technologies are in place for incorporating binding cations into red mud, approximately 6 million tonnes of additional CO(2) can be captured and stored in the red mud while the hazardousness of red mud is simultaneously reduced.
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Affiliation(s)
- Chunhua Si
- Centre for Ecological and Environmental Technologies, South China Agricultural University, Guangzhou 510642, China
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Chang EE, Pan SY, Chen YH, Tan CS, Chiang PC. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed. JOURNAL OF HAZARDOUS MATERIALS 2012; 227-228:97-106. [PMID: 22633879 DOI: 10.1016/j.jhazmat.2012.05.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 01/09/2012] [Accepted: 05/04/2012] [Indexed: 05/28/2023]
Abstract
Carbon dioxide (CO(2)) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO(2) sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min(-1) of a pure CO(2) stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65°C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate.
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Affiliation(s)
- E-E Chang
- Department of Biochemistry, Taipei Medical University, Taipei, Taiwan
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Cárdenas-Escudero C, Morales-Flórez V, Pérez-López R, Santos A, Esquivias L. Procedure to use phosphogypsum industrial waste for mineral CO2 sequestration. JOURNAL OF HAZARDOUS MATERIALS 2011; 196:431-435. [PMID: 21982535 DOI: 10.1016/j.jhazmat.2011.09.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Revised: 09/07/2011] [Accepted: 09/12/2011] [Indexed: 05/31/2023]
Abstract
Industrial wet phosphoric acid production in Huelva (SW Spain) has led to the controversial stockpiling of waste phosphogypsum by-products, resulting in the release of significant quantities of toxic impurities in salt marshes in the Tinto river estuary. In the framework of the fight against global climate change and the effort to reduce carbon dioxide emissions, a simple and efficient procedure for CO(2) mineral sequestration is presented in this work, using phosphogypsum waste as a calcium source. Our results demonstrate the high efficiency of portlandite precipitation by phosphogypsum dissolution using an alkaline soda solution. Carbonation experiments performed at ambient pressure and temperature resulted in total conversion of the portlandite into carbonate. The fate of trace elements present in the phosphogypsum waste was also investigated, and trace impurities were found to be completely transferred to the final calcite. We believe that the procedure proposed here should be considered not only as a solution for reducing old stockpiles of phosphogypsum wastes, but also for future phosphoric acid and other gypsum-producing industrial processes, resulting in more sustainable production.
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Affiliation(s)
- C Cárdenas-Escudero
- Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Sevilla, Av. Reina Mercedes s/n, 41012 Seville, Spain
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Dou B, Song Y, Liu Y, Feng C. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor. JOURNAL OF HAZARDOUS MATERIALS 2010; 183:759-765. [PMID: 20724072 DOI: 10.1016/j.jhazmat.2010.07.091] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/12/2010] [Accepted: 07/20/2010] [Indexed: 05/29/2023]
Abstract
The gas-solid reaction and breakthrough curve of CO(2) capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO(2) gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO(2) level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO(2) capture at 550°C. Calcium oxide sorbent after reaction can be easily regenerated at 900°C by pure N(2) flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO(2) were controlled by a combination of the surface chemical reaction and diffusion of product layer.
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Affiliation(s)
- Binlin Dou
- School of Energy and Power Engineering, Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology 116023, Dalian, China.
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Abstract
Silica or various silicate aerogels can be characterized by highly porous, open cell, low density structures. The synthesis parameters influence the three-dimensional porous structures by modifying the kinetics and mechanism of hydrolysis and condensation processes. Numerous investigations have shown that the structure of porous materials can be tailored by variations in synthesis conditions (e.g., the type of precursors, catalyst, and surfactants; the ratio of water/precursor; the concentrations; the medium pH; and the solvent). The objectives of this review are to summarize and elucidate the effects of chemical conditions on the nanoporous structure of sol-gel derived silicate aerogels.
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Environmental remediation and conversion of carbon dioxide (CO(2)) into useful green products by accelerated carbonation technology. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2010; 7:203-28. [PMID: 20195442 PMCID: PMC2819785 DOI: 10.3390/ijerph7010203] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 01/12/2010] [Indexed: 12/03/2022]
Abstract
This paper reviews the application of carbonation technology to the environmental industry as a way of reducing carbon dioxide (CO2), a green house gas, including the presentation of related projects of our research group. An alternative technology to very slow natural carbonation is the co-called ‘accelerated carbonation’, which completes its fast reaction within few hours by using pure CO2. Carbonation technology is widely applied to solidify or stabilize solid combustion residues from municipal solid wastes, paper mill wastes, etc. and contaminated soils, and to manufacture precipitated calcium carbonate (PCC). Carbonated products can be utilized as aggregates in the concrete industry and as alkaline fillers in the paper (or recycled paper) making industry. The quantity of captured CO2 in carbonated products can be evaluated by measuring mass loss of heated samples by thermo-gravimetric (TG) analysis. The industrial carbonation technology could contribute to both reduction of CO2 emissions and environmental remediation.
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