Periodic precipitation of cobalt hydroxide in agar gel: Effect of ionic strength

Kulkarni, Sunil D.; Mir, AB Rashid; Kulkarni, Preeti S.

doi:10.1016/j.molliq.2017.05.135

Cited by 12 publications

(16 citation statements)

References 23 publications

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“…As the diffusion front proceeds, the precipitate is deposited in the form of bands at specific distances. 5,6 A large number of Liesegang systems consisting of hydroxides, 7,8 sulfides, 9 chromates and dichromates, 10 and phosphates 11,12 are reported.…”

Section: Introductionmentioning

confidence: 99%

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO₃ + KBr) System in Agar Gel

et al. 2019

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A periodically precipitating system wherein interband distance successively decreases is known as revert Liesegang banding. The phenomenon is rare, and the underlying mechanism is implicit. In the present paper, the Liesegang system comprising of AgNO 3 and KBr as the outer and inner electrolyte pair showing revert banding in agar gel by employing a 1D experimental setup is studied under varying concentrations of participating species. Revert banding was observed under all the experimental conditions. The concentrations of inner and outer electrolytes were found to play a major role in reverting since they build the ionic strength inside Liesegang tubes. We hypothesize that the band reverting is the interplay of van der Waals and electrical double-layer interactions, and hence classical DLVO (Derjaguin–Landau–Verwey–Overbeek) theory can be applied to interpret reverting. We propose that revert deposition of precipitates is the outcome of flocculation and peptization of sols, which is the manifestation of balancing attractive and repulsive interactions acting on colloidal particles responsible for band formation.

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Section: Introductionmentioning

confidence: 99%

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO₃ + KBr) System in Agar Gel

et al. 2019

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“…The Liesegang bands formed in a gel due to the reaction CoCl 2 + 2NH 4 OH → Co(OH) 2 + 2NH 4 Cl have been studied extensively with well-established spatio-temporal characteristics. , To validate the RGB value method, we have also performed few experiments on this system. The photograph of this system is shown at the top of Figure A.…”

Section: Resultsmentioning

confidence: 99%

“…The tubes were allowed to stand in a vertical position for 3–4 weeks. During the experimental period, the extent of diffusion (the distance between the line corresponding to x = 0 and the precipitate boundary due to reaction–diffusion), number of rings formed, distance between successive bands, and widths of the bands were measured using a traveling microscope within an accuracy of 0.001 cm . A schematic shown in Figure depicts the conventional method as well as the RGB method for locating the band center.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…The center of the band is determined by selecting the upper and lower boundary of the bands. The most common experimental method to locate the band position is using a traveling microscope. , We have recently reported the use of closely spaced grids (2 mm apart) on the 2D pattern image for measuring the band location . However, it was observed that the error bars on the measurement of spatial characteristics in both methods are still considerable.…”

Section: Introductionmentioning

confidence: 99%

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Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Walimbe¹,

Takale²,

Kulkarni

et al. 2021

Langmuir

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In the present study, a method is described for precise determination of spatial characteristics of Liesegang bands formed by employing a classical 1D setup using a web-based free resource (). The method involves the compartmentalization of the information on each pixel into R (red), G (green), or B (blue) values from the pattern images obtained using a simple digital camera. The values can further be converted to absorbance values by using the system blank. Each trough (or peak) in the graph of RGB values (or absorbance values) corresponds to a band in the pattern. The method is employed to determine the spacing and width of the periodically precipitating AgCl, AgBr, and Co(OH)2 in an agar gel. It is observed that AgCl shows revert banding, and AgBr shows revert banding at the top of the tube and then diverges to regular banding at the bottom of the tube, whereas the Co(OH)2 patterns explicitly show regular banding under given experimental conditions. It is also observed that minute instabilities, such as the formation of secondary bands, can also be visualized by the present method.

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“…A very similar phenomena is observed in mineral deposits, which occurs over a much longer period of time, named Liesegang bands after the famous scientist who discovered it in 1896. Several researchers have studied this phenomenon in minerals (Kulkarni S.D. et al, 2017, Rajurkar N. et al, 2015, George J. et al, 2005and George J. et al, 2003 but in metals this phenomenon has not been studied so far.…”

Section: Methodsmentioning

confidence: 99%

Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors

Khan¹,

Bong²,

Rigit³

et al. 2018

IJET

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Overhead high voltage transmission conductors used worldwide are produced in several configurations. A multi-strand conductor of the type ACSR330 is typically used for 275 kV overhead transmission lines. The conductor is composed of 7 inner strands of Ultra High Strength Galvanized Steel for the mechanical support of the conductor and 26 strands of high conductivity Aluminum wires meant for power transfer over long distances. During the use, weather conditions and power fluctuations tend to degrade the properties of these conductors. In the present work, study of the state of galvanization and oxidation of an ACSR330 conductor is undertaken with a view to understand the effectiveness of the loss in corrosion protection and changes in the zinc coating on the galvanized steel strands after use for 25 to 30 years. The Scanning Electron Microscopy (SEM), X Ray Diffraction (XRD) and Energy Dispersive Analysis through X rays (EDAX) provide a very useful insight into the state of the conductor and gives important information to the strategic decision maker, whether or not to replace the conductor. It was observed in the present study that the zinc coating diffuses inside the steel strand under temperature and time effect. This unique study on the used conductors also reveals that the morphology of the coating and its interface structure changes significantly compared to an unused conductor of the same age.

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Periodic precipitation of cobalt hydroxide in agar gel: Effect of ionic strength

Cited by 12 publications

References 23 publications

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO₃ + KBr) System in Agar Gel

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO₃ + KBr) System in Agar Gel

Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors

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Periodic precipitation of cobalt hydroxide in agar gel: Effect of ionic strength

Cited by 12 publications

References 23 publications

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO3 + KBr) System in Agar Gel

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO3 + KBr) System in Agar Gel

Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors

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Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO₃ + KBr) System in Agar Gel

Revert Banding in One-Dimensional Periodic Precipitation of the (AgNO₃ + KBr) System in Agar Gel