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Dimble AK, Bagul ND, Walimbe PC, Kulkarni PS, Kulkarni SD. Hydroxide-Source-Dependent Polymorphism and Phase Stability of Cobalt(II) Hydroxides in Diffusion-Driven Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:18631-18641. [PMID: 39162248 DOI: 10.1021/acs.langmuir.4c02149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
Hydroxides of cobalt(II) exist predominantly in two polymorphic forms, namely, the blue-green α-form [α-Co(OH)2] and reddish β-form [β-Co(OH)2]. These hydroxides have a layered structure with interlayer galleries of around 7 and 4 Å, respectively, for α- and β-Co(OH)2. In most of the previous studies, both the polymorphs were synthesized separately, and a few of them showed that the α-form gets converted to a thermodynamically more stable β-form via physical processes. In the present work, we have optimized the conditions for the simultaneous synthesis of both polymorphs under identical conditions in the same reactor using the 1D reaction-diffusion framework by employing different outer electrolytes. We found that the polymorph chemistry of Co(OH)2 depends on the source and concentration of OH- rather than other reaction conditions or later physical transformation. The products are characterized to confirm their morphology, structure, and chemical environment. We observed that the use of NaOH and NH4OH as the OH- precursor leads to α-Co(OH)2 only; however, with NaOH, a continuous precipitate is formed, and with NH4OH, periodic precipitation is formed. On the other hand, with hydrazine (HYZ) as the OH- source, Liesegang bands of α-Co(OH)2 and β-Co(OH)2 as granules are formed throughout the diffusion reactor. Another intriguing observation on the HYZ system is that at its high concentration, the bands of α-Co(OH)2 get converted to β-Co(OH)2. We articulate the reasons and mechanism of those observations.
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Affiliation(s)
- Akshay K Dimble
- Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's, Sir Parashurambhau College, Tilak Road, Pune, Maharashtra 411 030, India
| | - Nikhil D Bagul
- Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's, Sir Parashurambhau College, Tilak Road, Pune, Maharashtra 411 030, India
| | - Prasad C Walimbe
- Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's, Sir Parashurambhau College, Tilak Road, Pune, Maharashtra 411 030, India
| | - Preeti S Kulkarni
- Post Graduate and Research Center, Department of Chemistry, MES Abasaheb Garware College, Karve Road, Pune 411 004, India
| | - Sunil D Kulkarni
- Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's, Sir Parashurambhau College, Tilak Road, Pune, Maharashtra 411 030, India
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Tootoonchian P, Holló G, Uzunlar R, Lagzi I, Baytekin B. Periodic Stratification of Colloids in a Liquid Phase Produced by a Precipitation Reaction and Gel Swelling. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:11049-11055. [PMID: 38757442 PMCID: PMC11140740 DOI: 10.1021/acs.langmuir.4c00533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024]
Abstract
Pattern formation is a frequent phenomenon occurring in animate and inanimate systems. The interplay between the mass transport of the chemical species and the underlying chemical reaction networks generates most patterns in chemical systems. Periodic precipitation is an emblematic example of reaction-diffusion patterns, in which the process generates a spatial periodic structure in porous media. Here, we use the dormant reagent method to produce colloidal particles of Prussian blue (PB) and PB analogues at the liquid-gel interface. The generated particles produced a stable periodic stratification pattern in time in the liquid phase placed on top of the solid hydrogel. The phenomenon is governed by periodic swelling of the gel driven by the osmotic stress and stability of the formed particles. To illustrate the phenomenon, we developed an extended reaction-diffusion model, which incorporated the gel swelling and sedimentation effect of the formed colloids and could qualitatively reproduce the pattern formation in the liquid phase.
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Affiliation(s)
| | - Gábor Holló
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Budapest H-1111, Hungary
| | - Rana Uzunlar
- Chemistry
Department, Bilkent University, Ankara 06800, Turkey
| | - Istvan Lagzi
- Department
of Physics, Institute of Physics, Budapest
University of Technology and Economics, Budapest H-1111, Hungary
- HU-REN−BME
Condensed Matter Physics Research Group, Budapest University of Technology and Economics, Budapest H-1111, Hungary
| | - Bilge Baytekin
- Chemistry
Department, Bilkent University, Ankara 06800, Turkey
- UNAM
National Nanotechnology Research Center, Bilkent University, Ankara 06800, Turkey
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Farkas S, Gazdag F, Detrich M, Mészáros M, Holló G, Schuszter G, Lagzi I. Formation of Precipitation Ellipsoidal Disks and Spheres in the Wake of a Planar Diffusion Front. J Phys Chem Lett 2023; 14:10382-10387. [PMID: 37955575 PMCID: PMC10683069 DOI: 10.1021/acs.jpclett.3c02295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/11/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
Pattern formation is one of the examples of self-organization. In the generation of patterns, the coupling between the mass transport of the chemical species and their chemical reactions plays an important role. Periodic precipitation (Liesegang phenomenon) is a type of pattern formation in which layered precipitation structures form in the wake of the diffusion front. Here, we show a new type of precipitation pattern formation in zeolitic imidazolate framework-67 in a solid hydrogel column in a test tube manifested in the generation of precipitation ellipsoidal disks and spheres in the wake of the planar diffusion front of the outer electrolyte (2-methylimidazole). To increase the probability of the emergence of ellipsoidal disks and spheres, the surfaces of the borosilicate test tubes were chemically treated and functionalized. To support the experimental findings, we developed a reaction-diffusion model that qualitatively describes the formation of precipitate ellipsoidal disks and spheres in a test tube.
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Affiliation(s)
- Szabolcs Farkas
- Department
of Physics, Budapest University of Technology
and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Ferenc Gazdag
- Department
of Physics, Budapest University of Technology
and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- Mihály
Fazekas High School, Horváth Mihály tér 8, H-1082 Budapest, Hungary
| | - Márton Detrich
- Department
of Physics, Budapest University of Technology
and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- Mihály
Fazekas High School, Horváth Mihály tér 8, H-1082 Budapest, Hungary
| | - Márton Mészáros
- Department
of Physics, Budapest University of Technology
and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Gábor Holló
- Department
of Fundamental Microbiology, University
of Lausanne, CH-1015 Lausanne, Switzerland
| | - Gábor Schuszter
- Department
of Physical Chemistry and Materials Science, University of Szeged, Rerrich Béla tér 1, H-6720 Szeged, Hungary
| | - István Lagzi
- Department
of Physics, Budapest University of Technology
and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
- ELKH-BME
Condensed Matter Research Group, Budapest
University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
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Walimbe P, Itatani M, Kulkarni P, Lagzi I, Kulkarni S. A Quasi Universal Matalon-Packter Law for a Periodically Precipitating System of Iron(II) Hydroxide Involving Volumes and Concentrations of the Invading Electrolyte. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:13420-13429. [PMID: 37703058 DOI: 10.1021/acs.langmuir.3c00778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
The Matalon-Packter (MP) empirical law of periodically precipitating (Liesegang phenomenon) systems under non-equilibrium conditions describes the dependence of the periodicity (spacing coefficient) on the initial concentration of the outer electrolyte. We aim to present the MP law in a more generalized form using a realistic approach wherein mass transfer in the gel column plays a role instead of the initial concentrations. This work is an attempt to make such progress. The Liesegang bands of Fe(OH)2 were studied by varying the reservoir concentrations (c) and volumes (V) of the outer electrolyte (NH4OH). The spacing coefficient was found to be a function of the volume and concentration of the outer electrolyte. It was observed that the amount of chemical substance (cV) and the average molar diffusion flux (Fdiff) of the ions of the outer electrolyte could be a unifying quantity for expressing the MP law instead of the initial electrolyte concentration. We demonstrated that a single model is possible for a system, irrespective of the V value. Three different volumes were employed, and the calculations were performed under small, intermediate, and larger reservoir volume regimes. Interestingly, a single model was observed for the diffusion coefficients for all of the Fdiff values.
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Affiliation(s)
- Prasad Walimbe
- Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's Sir Parashurambhau College, Tilak Road, Pune 411 030, Maharashtra, India
| | - Masaki Itatani
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Müegytem rkp. 3, H-1111 Budapest, Hungary
| | - Preeti Kulkarni
- Post Graduate and Research Center, Department of Chemistry, MES Abasaheb Garware College, Karve Road, Pune 411 004, India
| | - István Lagzi
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Müegytem rkp. 3, H-1111 Budapest, Hungary
- ELKH-BME Condensed Matter Research Group, Budapest University of Technology and Economics, Müegytem rkp. 3, H-1111 Budapest, Hungary
| | - Sunil Kulkarni
- Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's Sir Parashurambhau College, Tilak Road, Pune 411 030, Maharashtra, India
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Takale KD, Watwe VS, Walimbe PC, Kulkarni PS, Kulkarni SD. Cu(II)-Metallized Three-Layered Cu-8HQ Complex with Hierarchical Crystallite Morphologies Synthesized via Reaction-Diffusion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:2641-2651. [PMID: 36779677 DOI: 10.1021/acs.langmuir.2c03080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Self-organization of regular band patterns of the precipitate via a reaction-diffusion (RD) framework is called Liesegang phenomenon. This non-equilibrium system is emerging as an efficient method for synthesizing materials with unique morphologies that may have desired properties. The formation of continuous precipitation inside a band with poor control over the shape and size of sparingly soluble salts has been well documented. However, only a few reports on forming organic-inorganic bonds are available. In the present work, we demonstrate the formation of 2D frameworks of bis-(8-hydroxyquinoline) copper(II) in the agar gel via RD. The macroscopic particles were dumbbell-shaped, with aspect ratios ranging from 2.7 (inner bands) to 0.7 (outer bands). The particles were composed of ribbon-shaped crystallites at the microscopic level, each with three layers of parallelogram prismatic monoclinic sheets stacked over one another, which could easily be exfoliated. The powder X-ray diffraction patterns at low angles and the surface areas of the crystallites indicated the formation of metal-organic frameworks. It was observed that the sizes of the particles could be tuned by controlling the extent of diffusion using reactant concentrations. Since such heterostructures have energy storage capacity, the cyclic voltammograms of the unexfoliated and exfoliated materials showed that they fall in the pseudocapacitor category with potential application as the electrode material. The frameworks were further characterized by techniques such as optical and electron microscopy, X-ray diffraction, IR spectroscopy, and UV-visible spectrophotometry.
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Affiliation(s)
- Kiran D Takale
- Post Graduate and Research Center, Department of Chemistry, S.P.Mandali's Sir Parashurambhau College [Savitribai Phule Pune University (formerly University of Pune)], Tilak Road, Maharashtra, Pune 411 030, India
| | - Varuna S Watwe
- Post Graduate and Research Center, Department of Chemistry, MES Abasaheb Garware College [Savitribai Phule Pune University (formerly University of Pune)], Karve Road, Pune 411 004, India
| | - Prasad C Walimbe
- Post Graduate and Research Center, Department of Chemistry, S.P.Mandali's Sir Parashurambhau College [Savitribai Phule Pune University (formerly University of Pune)], Tilak Road, Maharashtra, Pune 411 030, India
| | - Preeti S Kulkarni
- Post Graduate and Research Center, Department of Chemistry, MES Abasaheb Garware College [Savitribai Phule Pune University (formerly University of Pune)], Karve Road, Pune 411 004, India
| | - Sunil D Kulkarni
- Post Graduate and Research Center, Department of Chemistry, S.P.Mandali's Sir Parashurambhau College [Savitribai Phule Pune University (formerly University of Pune)], Tilak Road, Maharashtra, Pune 411 030, India
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Automated monitoring the kinetics of homogeneous and heterogeneous chemical processes using a smartphone. Sci Rep 2022; 12:15774. [PMID: 36131006 PMCID: PMC9492685 DOI: 10.1038/s41598-022-20123-9] [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: 07/11/2022] [Accepted: 09/08/2022] [Indexed: 11/08/2022] Open
Abstract
Heterogeneous chemical processes occupy a pivotal position in many fields of applied chemistry. Monitoring reaction kinetics in such heterogeneous systems together with challenges associated with ex-situ analytical methodologies can lead to inaccurate information about the nature of the catalyst surfaces as well as information about the steps involved. The present work explores the possibility of kinetic measurements of chemical reactions and adsorption processes of homogeneous and heterogeneous systems through the variation of RGB intensities of digital images using a smartphone combined with a program written in Python to accelerate and facilitate data acquisition. In order to validate the method proposed, the base promoted hydrolysis of 4-nitrophenyl acetate was initially investigated. The rate constants obtained through RGB analysis (0.01854 min-1) is almost identical to that using traditional UV-Vis spectroscopy (0.01848 min-1). The proposed method was then applied to monitor the kinetics of three heterogeneous processes: (1) reduction of 4-nitrophenolate in the presence of dispersed Pd/C; (2) decomposition of methyl orange with TiO2; and (3) adsorption of rhodamine on montmorillonite. In general, the method via digital images showed high reproducibility and analytical frequency, allowing the execution of simultaneous analyses, with an accuracy comparable to UV-Vis spectrophotometry. The method developed herein is a practical and valuable alternative for obtaining kinetic data of heterogeneous reactions and processes where a color change is involved, bypassing sampling collection and processing which decreases analytical frequency and may lead to data errors.
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Walimbe PC, Kulkarni PS, Kulkarni SD. Obstruction scaling model for the diffusion of the outer electrolyte leading to Liesegang patterns of (AgNO3 + KCl) system in agarose hydrogel. CHEMICAL PAPERS 2021. [DOI: 10.1007/s11696-021-01858-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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