Journal of Crystallization Process and Technology

Journal Information
ISSN / EISSN : 2161-7678 / 2161-7686
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 115
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Elmira Alamanova, Nasira Shyytyeva, Zhyldyz Berdalievа, Nurzat Abdyldaeva, Astra Duishonbaeva, Zhypargul Abdullaeva
Journal of Crystallization Process and Technology, Volume 10, pp 1-9;

Layered metal-organic polymer [Co(L)6](NO3)2 was obtained (where, L = C3H4N2) and structurally characterized by X-Ray diffraction (XRD) analysis. Crystals have trigonal structure: a = b = 12.3555(10) Ǻ, c = 14.4833(3) Ǻ; α = β = 90˚; γ = 120˚; V = 1914.78(5) Ǻ; R3, Z = 3. The structure of the complex consists of discrete [Co(L)6]2+ cations and anions. The Co2+ ion has a centrosymmetric octahedron configuration with a coordination site—CoN6. The ligand is coordinated monodentate through the pyridine nitrogen atom (N3) to the Co2+ ion with an average Co-N bond distance of 2.1590 Ǻ. Molecules in the coordination polymer are additionally linked by intermolecular hydrogen bonds through the pyrrole nitrogen atom (-N-H) and oxygen of the nitrate group with the formation of a polymer chain of the type: N-H…O. The chains are linked in layers along the (001) plane.
Chao-Wan Chang, Chi-Rung Lee, Gene-Hsiang Lee
Journal of Crystallization Process and Technology, Volume 10, pp 11-21;

The synthesis and structures of two novel zwitterionic ruthenium triazolato complexes are reported. The treatment of the ruthenium azido complex [Ru]-N3 (1, [Ru] = (η5-C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) with an excess of ethyl propiolate in CHCl3 or CH2Cl2 under ambient conditions for 15 days results in the formation of a mixture of the Z- and E-forms of N(1)-bound ruthenium 3-ethylacryl-4-carboxylate-3H-1,2,3-triazolato complexes [Ru]N3(CH=CHCO2Et)C2H(CO2) (Z-3) and (E-3) in a ratio of ca. 5:2. The structures of E-3 and Z-3 were confirmed by single-crystal X-ray diffraction analysis and fully characterized by 1H, 31P, 13C NMR and IR spectroscopy, mass spectrometry, and elemental analysis. The negatively charged carboxylate moieties of the zwitterionic ruthenium triazolato complexes Z-3 and Z-3 are highly nucleophilic and reactive toward a variety of electrophiles, making Z-3 and Z-3 potential starting materials for the development of biologically active 1,2,3-triazole derivatives.
Rui Zhang, Xuezhong Wang, Yang Zhang, Tao Liu
Journal of Crystallization Process and Technology, Volume 09, pp 13-38;

Crystal shape distribution, i.e. the multidimensional size distribution of crystals, is of great importance to their down-stream processing such as in filtration as well as to the end-use properties including the dissolution rate and bioavailability for crystalline pharmaceuticals. Engineering crystal shape and shape distribution requires knowledge about the growth behavior of different crystal facets under varied operational conditions e.g. supersaturations. Measurement of the facet growth rates and growth kinetics of static crystals in a crystallizer without stirring has been reported previously. Here attention is given to study on real-time characterization of the 3D facet growth behavior of crystals in a stirred tank where crystals are constantly moving and rotating. The measurement technique is stereo imaging and the crystal shape reconstruction is based on a stereo imaging camera model. By reference to a case study on potash alum crystallization, it is demonstrated that the crystal size and shape distributions (CSSD) of moving and rotating potash alum crystals in the solution can be reconstructed. The moving window approach was used to correlate 3D face growth kinetics with supersaturation (in the range 0.04 - 0.12) given by an ATR FTIR probe. It revealed that {100} is the fastest growing face, leading to a rapid reduction of its area, while the {111} face has the slowest growth rate, reflected in its area continuously getting larger.
Nidhi Yaduvanshi, Deepak Kumar, Nikhil Rastogi, Ashok Kumar
Journal of Crystallization Process and Technology, Volume 09, pp 1-11;

A single scan has been performed in Differential Scanning Calorimetry (DSC) at a heating rate of 15oC/min under non-isothermal conditions to investigate the crystallization kinetics of glassy Se90Sb10-xAgx alloys (where x = 2, 4, 6, 8). For this purpose, Handerson’s theory based on non-isothermal method for thermal analysis of single-scan DSC data has been used. The activation energy of crystallization and order parameter has been determined and composition dependence of these parameters has been discussed.
Grygoriy S. Pekar, Alexandr F. Singaеvsky, Myhailo M. Lokshin, Ilya A. Vasin, Oleksandr Dubikovskyi
Journal of Crystallization Process and Technology, Volume 09, pp 39-47;

Unconventional ways to improve the efficiency of purification of two different semiconductor materials of current interest, ZnO and Ge, are described. It is shown that, by using chemically assisted vapour transport of ZnO with carbon as a transporting agent, the degree of chemical purity of ZnO can be increased by more than an order of magnitude. It is also found that heating of the molten Ge in the experimentally determined narrow (about 20?C wide) temperature range in which an intense evaporation of certain substances is observed, leads to a significant reduction of germanium contamination. As a result, a subsequent deep purification of pre-heat treated germanium by zone refining can be achieved at twice reduced (as compared with “non-treated” Ge) number of passes of a boat with germanium through the melting zones. Thus, the Ge purification process becomes faster, cheaper and more efficient.
Daniel Selzer, Burkard Spiegel,
Journal of Crystallization Process and Technology, Volume 08, pp 1-17;

Crystal nucleation is important to control the product properties in industrial crystallization processes. To investigate crystallization phenomena, methods which rely on microscopic volumes have gained relevance over the last decade. Microfluidic devices are suitable for carrying out crystallization experiments based on a large set of individual droplets in the nanoliter range. In this work, we propose a simple method to manufacture such devices from polycarbonate as an alternative to conventional chips made of poly (dimethylsiloxane). The microfluidic device consists of two main functional parts: A T-junction for droplet generation and a section for storage and observation of up to 400 individual droplets. Using these manufactured devices, it is easy to produce and store highly monodisperse droplets of substances that require either a hydrophilic or hydrophobic surface of the microchannel. Since crystal nucleation is a stochastic process which depends on the sample volume, a reproducible droplet volume is of great importance for crystallization experiments. The versatile applicability of the manufactured devices is demonstrated for substances which are used in different crystallization applications, for example, solution crystallization (aqueous potassium nitrate solution) and melt crystallization (ethylene glycol distearate). Finally, we demonstrate that the manufactured microfluidic devices in our experimental setup can be used to conduct crystal nucleation measurements. Based on these measurements we discuss our results with respect to state-of-the-art nucleation models.
Metogbe B. Djihouessi, Sofiath Onifade, Martin P. Aina, Hervé E. Labité, François De Paule Codo
Journal of Crystallization Process and Technology, Volume 08, pp 18-32;

This paper presented the first part of the studies about the development of a tool for groundwater contamination prediction, conducted by the Laboratory of Sciences and Technology of Water (UAC/Benin). The investigation made consisted in estimating the combined effect of retardation factor and biodegradation on migration processes of leachate, in the underlying soils of household waste dumpsites, without active safety barrier. Leachate infiltration tests for different initial conditions were made on soil columns and the breakthrough curves were traced for electrical conductivity, the 5 day biochemical oxygen demand (BOD5) and total kjeldahl nitrogen TKN. A mathematical migration model was developed and solved numerically by finite difference method and implemented with Matlab R2013a. Thus, the calibration of the model was made with electric conductivity data by determining the dispersion coefficient of the studied soils (D = 0.96 cm2/min). Simulations for model verification showed that the established model can perfectly predict the migration of biodegradable organic pollution (BOD5) but did not give conclusive results for the monitoring of nitrogenous organic matter (TKN). The influence of the retardation factor on the migration of biodegradable organic pollutants in soils was linear, while the biodegradation rate of the organic material on migration showed an exponential pattern.
Noopur Rathi,
Journal of Crystallization Process and Technology, Volume 08, pp 73-87;

Batch crystallization studies of curcumin from hydrotropic solutions of sodium cumenesulphonate (NaCS) and of cinnamic acid from a photosensitive hydrotropic medium of sodium cinnamate (Na-CIN) were carried out, in an agitated reactor for the effect of alternate heating and cooling cycles on crystal morphology. The crystal characterization by Scanning electron microscopy (SEM) and crystal size distribution (CSD) showed formation of spheroidal curcumin crystals while cinnamic acid formed porous aggregates when subjected to thermal cycles. The UV irradiation of cinnamic acid however showed no formation of the aggregates. The type of hydrotrope used and the initial crystal morphologies of curcumin and cinnamic acid are shown to be important factors to result in a different behaviour of the crystal morphology upon thermal cycles. The CSD data were effectively used for estimation of nucleation and growth rate parameters.
Amel Adjimi, Meryem Lamri Zeggar, Nadhir Attaf, Mohammed Salah Aida
Journal of Crystallization Process and Technology, Volume 08, pp 89-106;

In the present work, undoped (SnO2) and fluorine-doped tin oxide (FTO) thin films were prepared by sol-gel process using a solution composed of (SnCl2, H2O), (NH4F), and ethanol mixture. The fluorine concentration effect on structural, optical and electrical properties of SnO2 films is investigated. The electrical properties of FTO films prepared by sol gel remain relatively lower than the ones deposited by other techniques. In present paper, we try to elucidate this difference. Films composition and the FTIR analysis, of films and formed precipitate during film growth, indicate that few amounts of fluorine are incorporated in SnO2 network, most of fluorine atoms remain in the solution. The films resistivity is reduced from 1.1 Ω·cm for undoped films to 3 × 10-2 Ω·cm for 50 wt.% doped FTO, but remains higher than the reported ones in the literature. This high resistivity is explained in terms of fluorine bonding affinity in the solution.
Xiaoxin Zhang, Semiramis Friedrich, Bernd Friedrich
Journal of Crystallization Process and Technology, Volume 08, pp 33-55;

Purification is a primary application of zone melting, in which the improvement of efficiency, production yield and minimum achievable impurity level are always the research focus due to the increasing demand for high purity metals. This paper has systematically outlined the whole development of related research on zone refining of metals including basic theories, variants of zone refining, parametric optimization, numerical models, and high purity analytical methods. The collection of this information could be of good value to improve the refining efficiency and the production of high purity metals by zone refining.
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