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Kato K, Hotta M, Koga N. Water vapor effect on the physico-geometrical reaction pathway and kinetics of the multistep thermal dehydration of calcium chloride dihydrate. Phys Chem Chem Phys 2024. [PMID: 38916484 DOI: 10.1039/d4cp01870b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
This study investigated how water vapor influences the reaction pathway and kinetics of the multistep thermal dehydration of inorganic hydrates, focusing on CaCl2·2H2O (CC-DH) transforming into its anhydride (CC-AH) via an intermediate of its monohydrate (CC-MH). In the presence of atmospheric water vapor, the thermal dehydration of CC-DH stoichiometrically proceeded through two distinct steps, resulting in the formation of CC-AH via CC-MH under isothermal conditions and linear nonisothermal conditions at a lower heating rate (β). Irrespective of atmospheric water vapor pressure (p(H2O)), these reaction steps were kinetically characterized by a physico-geometrical consecutive process involving the surface reaction and phase boundary-controlled reaction, which was accompanied by three-dimensional shrinkage of the reaction interface. In addition, a significant induction period was observed for the second reaction step, that is, the thermal dehydration of CC-MH intermediate to form CC-AH. With increasing p(H2O), a systematic increase in the apparent Arrhenius parameters was observed for the first reaction step, that is, the thermal dehydration of CC-DH to form CC-MH, whereas the second reaction step exhibited unsystematic variations of the Arrhenius parameters. At a larger β in the presence of atmospheric water vapor, the first and second reaction steps partially overlapped; moreover, an alternative reaction step of the thermal dehydration of CC-MH to form CaCl2·0.3H2O was observed between these reaction steps. The physico-geometrical phenomena influencing the reaction pathway and kinetics of the multistep thermal dehydration were elucidated by considering the effects of atmospheric and self-generated water vapor in a geometrically constrained reaction scheme.
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Affiliation(s)
- Kazuki Kato
- Department of Science Education, Division of Educational Sciences, Graduate School of Humanities and Social Sciences, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524, Japan.
| | - Mito Hotta
- Department of Science Education, Division of Educational Sciences, Graduate School of Humanities and Social Sciences, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524, Japan.
| | - Nobuyoshi Koga
- Department of Science Education, Division of Educational Sciences, Graduate School of Humanities and Social Sciences, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524, Japan.
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Kato K, Koga N. The physico-geometrical reaction pathway and kinetics of multistep thermal dehydration of calcium chloride dihydrate in a dry nitrogen stream. Phys Chem Chem Phys 2024; 26:12358-12371. [PMID: 38595319 DOI: 10.1039/d4cp00790e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Several inorganic hydrates exhibit reversible reactions of thermal dehydration and rehydration, which is potentially applicable to thermochemical energy storage. Detailed kinetic information on both forward and reverse reactions is essential for refining energy storage systems. In this study, factors determining the reaction pathway and kinetics of the multistep thermal dehydration of inorganic hydrates to form anhydride via intermediate hydrates were investigated as exemplified by the thermal dehydration of CaCl2·2H2O (CC-DH) in a stream of dry N2. The formation of CaCl2·H2O (CC-MH) as the intermediate hydrate is known during the thermal dehydration of CC-DH to form its anhydride (CC-AH). However, the two-step kinetic modeling based on the chemical reaction pathway considering the formation of the CC-MH intermediate failed in terms of the reaction stoichiometry and kinetic behavior of the component reaction steps. The kinetic modeling was refined by considering the physico-geometrical reaction mechanism and the self-generated reaction conditions to be a three-step reaction. The multistep reaction was explained as comprising the surface reaction of the thermal dehydration of CC-DH to CC-AH and subsequent contracting geometry-type reactions from CC-DH to CC-MH and from CC-MH to CC-AH occurring consecutively in the core of the reacting particles surrounded by the surface product layer of CC-AH. The acceleration of the linear advancement rate of the reaction interface during both contracting geometry-type reactions was revealed through multistep kinetic analysis and was described by a decrease in the water vapor pressure at the reaction interface as the previous reaction step proceeded and terminated.
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Affiliation(s)
- Kazuki Kato
- Department of Science Education, Division of Educational Sciences, Graduate School of Humanities and Social Sciences, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524, Japan.
| | - Nobuyoshi Koga
- Department of Science Education, Division of Educational Sciences, Graduate School of Humanities and Social Sciences, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524, Japan.
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Buryakovskaya OA, Maslakov KI, Borshchev NO, Ambaryan GN, Butyrin AV, Vlaskin MS. Silver-Assisted Hydrogen Evolution from Aluminum Oxidation in Saline Media. Molecules 2024; 29:530. [PMID: 38276608 PMCID: PMC10818649 DOI: 10.3390/molecules29020530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/02/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
A swarf of aluminum alloy with high corrosion resistance and ductility was successfully converted into fine hydro reactive powders via ball milling with silver powder and either lithium chloride or gallium. The latter substances significantly intensified particle size reduction, while silver formed 'cathodic' sites (Ag, Ag2Al), promoting Al corrosion in aqueous saline solutions with hydrogen generation. The diffraction patterns, microphotographs, and elemental analysis results demonstrated partial aluminum oxidation in the samples and their contamination with tungsten carbide from milling balls. Those factors were responsible for obtaining lower hydrogen yields than expected. For AlCl3 solution at 60 °C, Al-LiCl-Ag, Al-LiCl, Al-Ga-Ag, and Al-Ga composites delivered (84.6 ± 0.2), (86.8 ± 1.4), (80.2 ± 0.5), and (76.7 ± 0.7)% of the expected hydrogen, respectively. Modification with Ag promoted Al oxidation, thus providing higher hydrogen evolution rates. The samples with Ag were tested in a CaCl2 solution as well, for which the reaction proceeded much more slowly. At a higher temperature (80 °C) after 3 h of experiment, the corresponding hydrogen yields for Al-LiCl-Ag and Al-Ga-Ag powders were (46.7 ± 2.1) and (31.8 ± 1.9)%. The tested Ag-modified composite powders were considered promising for hydrogen generation and had the potential for further improvement to deliver higher hydrogen yields.
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Affiliation(s)
- Olesya A. Buryakovskaya
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia; (N.O.B.); (G.N.A.); (A.V.B.); (M.S.V.)
| | | | - Nikita O. Borshchev
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia; (N.O.B.); (G.N.A.); (A.V.B.); (M.S.V.)
| | - Grayr N. Ambaryan
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia; (N.O.B.); (G.N.A.); (A.V.B.); (M.S.V.)
| | - Aleksey V. Butyrin
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia; (N.O.B.); (G.N.A.); (A.V.B.); (M.S.V.)
| | - Mikhail S. Vlaskin
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia; (N.O.B.); (G.N.A.); (A.V.B.); (M.S.V.)
- Algal Research and Bioenergy Lab, Department of Food Science and Technology, Graphic Era (Deemed to be University), Dehradun 248002, India
- Department of Environmental Safety and Product Quality Management, Peoples’ Friendship University of Russia, 117198 Moscow, Russia
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Zhu F, Liu H, Zhang W, Zhou Y, Wang X, Zhang Y, Fang C. Ab-initio investigation on ion-associated species and association process in Li[B(OH) 4] solution. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 213:423-429. [PMID: 30731254 DOI: 10.1016/j.saa.2019.01.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 01/13/2019] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
In this paper, the factors determining the spectroscopic characteristics of vsym-B(OH)4- band including coupling effect, hydrogen bonding effect, and direct contact effect in Li[B(OH)4] solutions are investigated by using ab initio calculation. The coupling effect between the liberations of water and [B(OH)4-] has a larger effect on vsym-B(OH)4- in solvent-shared ion pair (SIP) and monodentate contact ion pair (MCIP), but the smaller effect in bidentate contact ion pair (BCIP). Water molecule tends to hydrate to the middle position between the first sphere of B(OH)4- and outer-sphere of [Li(H2O)4+] and has a different effect on vsym-B(OH)4- in ion pairs. The direct contact effect and polarization effect lead to 19.7 cm-1 red shift of vsym-B(OH)4- in MCIP, and 0.4 cm-1 blue shift in BCIP. The association process in Li[B(OH)4] solution was also introduced by using Raman spectral evolution of vsym -B(OH)4- in the dehydration process.
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Affiliation(s)
- Fayan Zhu
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xingning 810008, China; Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of salt Lakes, Chinese Academy of Science, Xining, 810008, China
| | - Hongyan Liu
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xingning 810008, China; Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of salt Lakes, Chinese Academy of Science, Xining, 810008, China
| | - Wenqian Zhang
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xingning 810008, China; Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of salt Lakes, Chinese Academy of Science, Xining, 810008, China
| | - Yongquan Zhou
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xingning 810008, China; Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of salt Lakes, Chinese Academy of Science, Xining, 810008, China
| | - Xiufang Wang
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xingning 810008, China; Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of salt Lakes, Chinese Academy of Science, Xining, 810008, China
| | - Yunhong Zhang
- The Institute of Chemical Physics, School of Science, and School of Aerospace Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Chunhui Fang
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xingning 810008, China; Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Qinghai Institute of salt Lakes, Chinese Academy of Science, Xining, 810008, China.
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Molecular dynamics simulation study on distinctive hydration characteristics of highly coordinated calcium chloride complexes. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.10.136] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Ma S, Chai J, Wu K, Wan Z, Xiang Y, Zhang J, Fan Z. Experimental and mechanism research on volatilization characteristics of HCl in desulfurization wastewater evaporation process using high temperature flue gas. J IND ENG CHEM 2018. [DOI: 10.1016/j.jiec.2018.05.045] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Li HJ, Yan D, Cai HQ, Yi HB, Min XB, Xia FF. Insights into water-mediated ion clustering in aqueous CaSO 4 solutions: pre-nucleation cluster characteristics studied by ab initio calculations and molecular dynamics simulations. Phys Chem Chem Phys 2018; 19:11390-11403. [PMID: 28422226 DOI: 10.1039/c7cp00428a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular structure of growth units building crystals is a fundamental issue in the crystallization processes from aqueous solutions. In this work, a systematic investigation of pre-nucleation clusters and their hydration characteristics in aqueous CaSO4 solutions was performed using ab initio calculations and molecular dynamics (MD) simulations. The results of ab initio calculations and MD simulations indicate that the dominant species in aqueous CaSO4 solutions are monodentate ion-associated structures. Compared with charged ion clusters, neutral clusters are more likely to be present in an aqueous CaSO4 solution. Neutral (CaSO4)m clusters are probably the growth units involved in the pre-nucleation or crystallization processes. Meanwhile, hydration behavior around ion associated species in aqueous CaSO4 solutions plays an important role in related phase/polymorphism selections. Upon ion clustering, the residence of some water molecules around Ca2+ in ion-associated species is weakened while that of some bridging waters is enhanced due to dual interaction by Ca2+ and SO42-. Some phase/polymorphism selections can be achieved in aqueous CaSO4 solutions by controlling the hydration around pre-nucleation clusters. Moreover, the association trend between calcium and sulfate is found to be relatively strong, which hints at the low solubility of calcium sulfate in water.
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Affiliation(s)
- Hui-Ji Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
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Pathak AD, Tranca I, Nedea SV, Zondag HA, Rindt CCM, Smeulders DMJ. First-Principles Study of Chemical Mixtures of CaCl 2 and MgCl 2 Hydrates for Optimized Seasonal Heat Storage. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:20576-20590. [PMID: 28983386 PMCID: PMC5623945 DOI: 10.1021/acs.jpcc.7b05245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/09/2017] [Indexed: 06/07/2023]
Abstract
Chloride-based salt hydrates form a promising class of thermochemical materials (TCMs), having high storage capacity and fast kinetics. In the charging cycles of these hydrates however hydrolysis might appear along with dehydration. The HCl produced during the hydrolysis degrades and corrodes the storage system. Our GGA-DFT results show that the enthalpy charge during proton formation (an important step in hydrolysis) is much higher for CaCl2·2H2O (33.75 kcal/mol) than for MgCl2·2H2O (19.55 kcal/mol). This is a strong indicator that hydrolysis can be minimized by appropriate chemical mixing of CaCl2 and Mg Cl2 hydrates, which is also confirmed by recent experimental studies. GGA-DFT calculations were performed to obtain and analyze the optimized structures, charge distributions, bonding indicators and harmonic frequencies of various chemical mixtures hydrates and compared them to their elementary salts hydrates. We have further assessed the equilibrium products concentration of dehydration/hydrolysis of the chemical mixtures under a wide range of operating conditions. We observed that chemical mixing leads to an increase of the onset hydrolysis temperature with a maximum value of 79 K, thus increasing the resistance against hydrolysis with respect to the elementary salt hydrates. We also found that the chemical mixing of CaCl2 and MgCl2 hydrates widens the operating dehydration temperature range by a maximum value of 182 K (CaMg2Cl6·2H2O) and lowers the binding enthalpy with respect to the physical mixture by ≈65 kcal/mol for TCM based heat storage systems.
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Pathak AD, Nedea S, van Duin ACT, Zondag H, Rindt C, Smeulders D. Reactive force field development for magnesium chloride hydrates and its application for seasonal heat storage. Phys Chem Chem Phys 2016; 18:15838-47. [DOI: 10.1039/c6cp02762h] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the development of the ReaxFF of MgCl2 hydrates and its application for seasonal heat storage. This study, indicate the validity of the ReaxFF approach for studying MgCl2 hydrates and provide important atomistic-scale insight of reaction kinetics and H2O transport.
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Affiliation(s)
| | - Silvia Nedea
- Energy Technology
- 5600 MB Eindhoven
- The Netherlands
| | - Adri C. T. van Duin
- Department of Mechanical and Nuclear Engineering
- Pennsylvania State University
- University Park
- USA
| | | | - Camilo Rindt
- Energy Technology
- 5600 MB Eindhoven
- The Netherlands
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