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Duchstein P, Löffler F, Zahn D. Efficient Assessment of 'Instantaneous pK' Values from Molecular Dynamics Simulations. Chemphyschem 2024; 25:e202300489. [PMID: 37927201 DOI: 10.1002/cphc.202300489] [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: 07/12/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
We present a molecular simulation approach to studying the role of local and momentary molecular environment for potential acid-base reactions. For this, we combine thermodynamic considerations on the pK of ionic species with rapid sampling of energy changes related to (de)protonation. Using dispersed carbonate ions in water as a reference, our approach aims at the fast assessment of the momentary protonation energy, and thus the 'instantaneous pK', of calcium-carbonate ion aggregates. The latter include transient complexes that are elusive to long sampling runs. This motivated the elaboration of approximate, yet particularly fast assessable sampling strategies. Along this line, we were able to characterize instantaneous pK values at a statistical accuracy of 0.4 pK units within sampling runs of only 10 ps duration, whereas statistical errors reduce to 0.1 pK units in 75 ps sampling runs, respectively. This readily enabled the required time resolution for the characterization of [Cax (CO3 )y ]2(x-y) aggregates with x=1,2 and y=1,2,3, respectively. In turn, the analysis of the pH-dependent nature of calcite-water interfaces and dynamically ordered liquid-like oxyanion polymers (dollop) domains is outlined at 10 ps resolution.
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Affiliation(s)
- Patrick Duchstein
- Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstraße 25, 91052, Erlangen, Germany
| | - Felix Löffler
- Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstraße 25, 91052, Erlangen, Germany
| | - Dirk Zahn
- Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstraße 25, 91052, Erlangen, Germany
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Wonglakhon T, Zahn D. On the Role of Amides and Imides for Understanding GaN Syntheses from Ammonia Solution: Molecular Mechanics Models of Ammonia, Amide and Imide Interactions with Gallium Nitride. Chemphyschem 2022; 23:e202200117. [PMID: 35588269 PMCID: PMC9400881 DOI: 10.1002/cphc.202200117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/23/2022] [Indexed: 11/29/2022]
Abstract
A key requisite to characterizing GaN precipitation from ammonia solution from molecular simulations is the availability of reliable molecular mechanics models for the interactions of gallium ions with NH3 , NH2- , and NH2- species, respectively. Here, we present a tailor-made force field which is fully compatible to an earlier developed GaN model, thus bridging the analyses of Ga3+ ions in ammonia solution with the aggregation of [Gax (NH)y (NH2 )z ]+3x-2y-z precursors and the modelling of GaN crystals. For this, quantum mechanical characterization of a series of Ga-coordination clusters is used for parameterization and benchmarking the generalized amber force field (GAFF2) and tailor-made refinements needed to achieve good agreement of both structural features and formation energy, respectively. The perspectives of our models for larger scale molecular dynamics simulations are demonstrated by the analyses of amide and imide defects arrangement during the growth of GaN crystal faces.
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Affiliation(s)
- Tanakorn Wonglakhon
- Lehrstuhl für Theoretische Chemie/Computer Chemie CentrumFriedrich-Alexander Universität Erlangen-NürnbergNägelsbachstraße 2591052ErlangenGermany
| | - Dirk Zahn
- Lehrstuhl für Theoretische Chemie/Computer Chemie CentrumFriedrich-Alexander Universität Erlangen-NürnbergNägelsbachstraße 2591052ErlangenGermany
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Wonglakhon T, Zahn D. Molecular dynamics simulation study of NH4+ and NH2− in liquid ammonia: interaction potentials, structural and dynamical properties. J Mol Model 2022; 28:127. [DOI: 10.1007/s00894-022-05110-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
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Numerical Simulation of Ammonothermal Crystal Growth of GaN—Current State, Challenges, and Prospects. CRYSTALS 2021. [DOI: 10.3390/cryst11040356] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Numerical simulations are a valuable tool for the design and optimization of crystal growth processes because experimental investigations are expensive and access to internal parameters is limited. These technical limitations are particularly large for ammonothermal growth of bulk GaN, an important semiconductor material. This review presents an overview of the literature on simulations targeting ammonothermal growth of GaN. Approaches for validation are also reviewed, and an overview of available methods and data is given. Fluid flow is likely in the transitional range between laminar and turbulent; however, the time-averaged flow patterns likely tend to be stable. Thermal boundary conditions both in experimental and numerical research deserve more detailed evaluation, especially when designing numerical or physical models of the ammonothermal growth system. A key source of uncertainty for calculations is fluid properties under the specific conditions. This originates from their importance not only in numerical simulations but also in designing similar physical model systems and in guiding the selection of the flow model. Due to the various sources of uncertainty, a closer integration of numerical modeling, physical modeling, and the use of measurements under ammonothermal process conditions appear to be necessary for developing numerical models of defined accuracy.
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Becker P, Wonglakhon T, Zahn D, Gudat D, Niewa R. Approaching Dissolved Species in Ammonoacidic GaN Crystal Growth: A Combined Solution NMR and Computational Study. Chemistry 2020; 26:7008-7017. [PMID: 32011786 PMCID: PMC7317737 DOI: 10.1002/chem.201904657] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/29/2020] [Indexed: 11/11/2022]
Abstract
Solutions of gallium trihalides GaX3 (X=F, Cl, Br, I) and their ammoniates in liquid ammonia were studied at ambient temperature under autogenous pressure by multinuclear (71 Ga, 35 Cl, 81 Br) NMR spectroscopy. To unravel the role of pH, the analyses were done both in absence and in presence of ammonium halides, which are employed as mineralizers during ammonoacidic gallium nitride crystal growth. While gallium trifluoride and its ammoniate were found to be too sparingly soluble to give rise to a NMR signal, the spectra of solutions of the heavier halides reveal the presence of a single gallium-containing species in all cases. DFT calculations and molecular dynamics simulations suggest the identification of this species as consisting of a [Ga(NH3 )6 ]3+ cation and up to six surrounding halide anions, resulting in an overall trend towards negative complex charge. Quantitative 71 Ga NMR studies on saturated solutions of GaCl3 containing various amounts of additional NH4 Cl revealed a near linear increase of GaCl3 solubility with mineralizer concentration of about 0.023 mol GaCl3 per mol NH4 Cl at room temperature. These findings reflect the importance of Coulombic shielding for the inhibition of oligomerization and precipitation processes and help to rationalize both the low solubility of gallium halides in neutral ammonia solution and, in turn, the proliferating effect of the mineralizer during ammonoacidic gallium nitride formation.
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Affiliation(s)
- Peter Becker
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Tanakorn Wonglakhon
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Dirk Zahn
- Department of Chemistry and Pharmacy, Friedrich Alexander University Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Dietrich Gudat
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Rainer Niewa
- Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
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Wonglakhon T, Zahn D. Interaction potentials for modelling GaN precipitation and solid state polymorphism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:205401. [PMID: 31961336 DOI: 10.1088/1361-648x/ab6cbe] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We outline a molecular mechanics model for the interaction of gallium and nitride ions ranging from small complexes to nanoparticles and bulk crystals. While the current GaN force fields allow the modelling of either bulk crystals or single ions dispersed in solution, our model covers both and hence paves the way to describing aggregate formation and crystal growth processes from molecular simulations. The key to this is the use of formal +3 and -3 charges on the gallium and nitride ions, whilst accounting for the charge transfer in GaN crystals by means of additional potential energy terms. The latter are fitted against experimental data of GaN in the wurtzite structure and benchmarked for the zinc-blende and rock-salt polymorphs. Comparison to quantum chemical references and experiment shows reasonable agreement of structures and formation energy of [GaN] n aggregates, elastic properties of the bulk crystal, the transition pressure of the wurtzite to rock-salt transformation and intrinsic point defects. Furthermore, we demonstrate force field transferability towards the modelling of GaN nanoparticles from simulated annealing runs.
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Affiliation(s)
- Tanakorn Wonglakhon
- Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany
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Pinatha Y, Polprasert C, Englande AJ. Product and cost perspectives of phosphorus recovery from human urine using solid waste ash and sea salt addition - A case of Thailand. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 713:136514. [PMID: 31951836 DOI: 10.1016/j.scitotenv.2020.136514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/28/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Phosphorus (P) recovery from human urine was evaluated using the addition of MgCl2, sea salt and solid-waste (SW) incinerated ashes. The study objectives were to assess and compare their efficiency for P recovery, costs of chemicals added and relevant crystal characteristics. Results from the experiments conducted between pH range of 7-11 revealed that P precipitation efficiency was increased to 89-97% and 72-88% when MgCl2 and sea salt were added, respectively. Precipitates obtained from both cases were found to contain 10.8-17.1% P dry weight which is superior to commercial fertilizer (8.80% P). Based on SEM-EDS examination and chemical equilibrium thermodynamics, about 83% and 68% of precipitates were in the form of struvite for the addition of MgCl2 and sea salt, respectively. Although 18% less struvite was formed with sea salt added, cost was found to be reduced from 4.07 USD·(kg P)-1 for MgCl2 addition to 2.91 USD·(kg P)-1 using sea salt addition, representing a 28% cost reduction. Furthermore, SW ashes added into the urine increased P recovery efficiency about 6-17%. Addition also lowered the costs to 1.75 and 1.68 USD·(kg P)-1 for SW fly ash and bottom ash, respectively. Thus, ash addition reduced cost and provided an alternative to landfill disposal. However, addition of SW bottom ash might result in recovered P solids with lead concentration exceeding the EC limit for inorganic fertilizer. In summary, results of this study have demonstrated a pragmatic way to recover P from human urine with the use of sea salt and ash as alternative Mg source and seed. Results indicate that this practice not only produces a good-quality fertilizer as struvite for sustainable P management, but also helps protect the water environment, and support circular economy of P in human ecosystem.
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Affiliation(s)
- Yada Pinatha
- Department of Sanitary Engineering, Faculty of Public Health, Mahidol University, Rajvithee Road, Bangkok 10400, Thailand; Center of Excellence on Environmental Health and Toxicology, Bangkok 10400, Thailand
| | - Chongchin Polprasert
- Department of Sanitary Engineering, Faculty of Public Health, Mahidol University, Rajvithee Road, Bangkok 10400, Thailand; Center of Excellence on Environmental Health and Toxicology, Bangkok 10400, Thailand.
| | - Andrew J Englande
- Department of Global Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA
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Annisa TN, Jung SH, Gupta M, Bae JY, Park JM, Lee HI. A Reusable Polymeric Film for the Alternating Colorimetric Detection of a Nerve Agent Mimic and Ammonia Vapor with Sub-Parts-per-Million Sensitivity. ACS APPLIED MATERIALS & INTERFACES 2020; 12:11055-11062. [PMID: 32046484 DOI: 10.1021/acsami.0c00042] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Thin polymeric films were developed for the vapor-phase sequential colorimetric detection of a nerve agent mimic and ammonia with high sensitivity. N-(4-Benzoylphenyl)acrylamide (BPAm), N,N-dimethylacrylamide (DMA), and (E)-2-(methyl(4-(pyridine-4yldiazenyl)phenyl)amino)ethyl acrylate (MPDEA, M1) were copolymerized via free radical polymerization (FRP) to yield p(BPAm-co-DMA-co-MPDEA), hereafter referred to as P1. P1 exhibits selective sensing properties toward diethyl chlorophosphate (DCP), a nerve agent mimic, in pure aqueous media. Upon the addition of DCP, the pyridine groups of P1 were quaternized with DCP, accompanied by a color change from yellow to pink due to the enhancement of the intramolecular charge transfer (ICT) effect. In situ generated quaternized P1, hereafter referred to as P2, after DCP sensing was used to selectively detect ammonia via dequaternization in an aqueous medium. Ammonia detection was indicated by a color change in the solution from pink back to yellow. A surface-immobilized P1 film was prepared and employed for the vapor-phase detection of DCP, demonstrating that an amount of as low as 2 ppm was detectable. Ammonia vapor was also successfully detected by the P2 film via the ammonia-triggered removal of the quaternized phosphates. Alternating exposure of the film to DCP and ammonia resulted in the corresponding color changes, thereby demonstrating the reversibility of the system. The reusability of the polymeric film for detecting DCP and ammonia in the vapor phase was confirmed by performing four sequential colorimetric detection cycles.
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Affiliation(s)
- Tiara Nur Annisa
- Department of Chemistry, University of Ulsan, Ulsan 680-749, Republic of Korea
| | - Seo-Hyun Jung
- Department of Chemistry, University of Ulsan, Ulsan 680-749, Republic of Korea
- Center for green fine chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Republic of Korea
| | - Moumita Gupta
- Department of Chemistry, University of Ulsan, Ulsan 680-749, Republic of Korea
| | - Ja Young Bae
- Center for green fine chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Republic of Korea
| | - Jong Mok Park
- Center for green fine chemicals, Korea Research Institute of Chemical Technology, Ulsan 44412, Republic of Korea
| | - Hyung-Il Lee
- Department of Chemistry, University of Ulsan, Ulsan 680-749, Republic of Korea
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