eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
1
7
10.30492/ijcce.2005.7625
7625
Gum Tragacanth Gels as a New Supporting Matrix for Immobilization of Whole-Cell
Maryam Otady
mm-otadi@yahoo.com
1
Ali Vaziri
2
Ali Akbar Seifkordi
3
Azadeh Kheirolomoom
4
Department of Biotechnology and Chemical Engineering, College of Science and Research, Islamic Azad University, Tehran, I.R. IRAN
Department of Biotechnology and Chemical Engineering, College of Science and Research, Islamic Azad University, Tehran, I.R. IRAN
Department of Chemical Engineering, Sharif University of Technology, Tehran, I.R. IRAN
Department of Chemical Engineering, Sharif University of Technology, Tehran, I.R. IRAN
We introduce a new smooth, non-toxic, biocompatible method for cross-linking of gum tragacanth (GT), a polysaccharide of natural origin, in order to serve as a new supporting matrix for immobilization systems. The modified gum is used as a matrix for the catalysis of the conversion of benzyl penicillin to 6-aminopenicillanic acid (6-APA) by means of Escherichia coli ATCC11105 with penicillin G acylase (PGA) activity. The results show that GT beads can not only serve as a proper matrix for immobilization, but show enhanced hydrolysis rate and stability compared to other immobilization systems used for this reaction. This signifies the potential of GT as a biocompatible matrix for immobilization and its positive prospects for use in more demanding immobilization applications where traditional matrices such as alginate may fall short. The effect of environmental factors, such as temperature, pH, and substrate concentration, have also been studied on the hydrolysis rate and compared with the other immobilizing systems used for the same reaction, such as calcium alginate. Under the optimal conditions, penicillin G conversion reached 91.5% after 6 h and remained over 80% after 45 repeated cycles of 6 h each.
https://ijcce.ac.ir/article_7625_215fbf4a621829f432c55734f9fbe0fb.pdf
Gum tragacanth
Immobilized whole-cell
Penicillin G acylase
Ionomer
Crosslink
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
9
14
10.30492/ijcce.2005.8103
8103
Synthesis of Hydrophobic Silicalite Adsorbent from Domestic Resources: The Effect of Alkalinity on the Crystal Size and Morphology
Davood Vakili
1
Mohammad Ali Attarnejad
2
Sayyed Kamal Massoodian
3
Mohammad Mahdi Akbarnejad
akbarnejadm@ripi.ir
4
Research Institute of Petroleum Industry (N.I.O.C.), Catalysis Research Center, P.O. Box 18745-4163, Tehran, I.R. IRAN
Research Institute of Petroleum Industry (N.I.O.C.), Catalysis Research Center, P.O. Box 18745-4163, Tehran, I.R. IRAN
Research Institute of Petroleum Industry (N.I.O.C.), Catalysis Research Center, P.O. Box 18745-4163, Tehran, I.R. IRAN
Research Institute of Petroleum Industry (N.I.O.C.), Catalysis Research Center, P.O. Box 18745-4163, Tehran, I.R. IRAN
A new polymorph crystalline silica composition having uniform pore dimensions were synthesized by calcining a crystalline hydrated alkyl-ammonium silicate. The pore dimensions approximately were 6 angstrom for silicalite-1 and 11 angstrom for silicalite-2 units. The silicalite-1 was prepared hydrothermally at a pH of about 10 from a reaction mixture consist of water, amorphous silica and a quaternary ammonium compound. Domestic water glass was ion-exchanged to produce silicasol. In this work we also investigated the influence of alkalinity percent in the starting gel mixture on the crystal shape and size.
https://ijcce.ac.ir/article_8103_4165a51427c209f35befef7b1a4a8e40.pdf
Silicalite
Polymorph crystalline silica
Amorphous silica
Tetrapropylammonium- bromide
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
15
24
10.30492/ijcce.2005.8104
8104
The Contribution of Molecular Diffusion in Silica Coating and Chemical Reaction in the Overall Rate of Reaction of Aluminum Hydroxide with Fluosilicic Acid
Mahmoud Bayat
mmahmood_in@yahoo.com
1
Abbas Taeb
2
Saeed Rastegar
3
Faculty of Chemical Engineering, Iran University of Science and Technology, P.O.Box 16765-163, Tehran, I.R.IRAN
Faculty of Chemical Engineering, Iran University of Science and Technology, P.O.Box 16765-163, Tehran, I.R.IRAN
Faculty of Polymer, Amirkabir University of Technology, P.O.Box 15875-4413, Tehran, I.R.IRAN
The kinetic of the heterogeneous chemical reaction of aluminum hydroxide and fluosilicic acid was studied. It was found that the diffusion of the reactants through the porous silica coating to the aluminum hydroxide surface and the interfacial chemical reaction between the diffusing reactant and aluminum hydroxide platelets control the overall reaction rate. These two phenomena were studied and their contributions to the overall reaction rate were derived using experimental data. By combining these terms a relation for the overall reaction rate was obtained. The activation energy of the chemical reaction was calculated to be 12 kcal/mol and the activation energy of the diffusion into the silica coating was found as 28 kcal/mol. A numerical procedure was adjusted to determine the variation of the specific surface area of un-reacted core, its average particle size and the specific surface area for mass transfer
https://ijcce.ac.ir/article_8104_9fe01a73bd871b55d3e0c4b7a57d338c.pdf
Heterogeneous reaction
Aluminum hydroxide
Fluosilicic acid
Aluminum fluoride
silica
Effective diffusion coefficient
Aggregation
Kinetics
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
25
36
10.30492/ijcce.2005.8105
8105
Accelerated Deactivation and Activity Recovery Studies of Ruthenium and Rhenium Promoted Cobalt Catalysts in Fischer-Tropsch Synthesis
Ahmad Tavasoli
tavassolia@khayam.ut.ac.ir
1
Ali Karimi
2
Abbas Ali Khodadadi
3
Yadollah Mortazavi
4
Mohammad Ali Mousavian
5
Research Institute of Petroleum Industry, P.O.Box 18745-4163, Tehran, I. R. IRAN
Research Institute of Petroleum Industry, P.O.Box 18745-4163, Tehran, I. R. IRAN
Department of Chemical Engineering, University of Tehran, P. O. Box 11365/4563, Tehran, I. R. IRAN
Department of Chemical Engineering, University of Tehran, P. O. Box 11365/4563, Tehran, I. R. IRAN
Department of Chemical Engineering, University of Tehran, P. O. Box 11365/4563, Tehran, I. R. IRAN
Accelerated deactivation of Co/Al2O3 catalysts in Fischer-Tropsch synthesis and the effect of Re and Ru as the catalytic promoters are reported. 15wt% Co/Al2O3 catalyst and 1wt% Ru and 1.4wt% Re promoted cobalt catalysts have been formulated and extensively characterized. The deactivation of the unpromoted cobalt catalyst and those promoted with Re and Ru were studied by accelerated method at 260oC. Different sources of deactivation were identified. The amount of activity recovery after regeneration at the conditions of low temperature treatment at 260oC and high temperature treatment at 400oC for the used promoted and unpromoted catalysts were detrmined. It was revealed that promoted catalyst deactivated faster than unpromoted ones. High temperature H2 treatment restored the catalytic activity of the catalysts more than 97.5%.
https://ijcce.ac.ir/article_8105_634cabe9374434e6459b27fa8c5cf811.pdf
Fischer-Tropsch
Cobalt
Ruthenium
Rhenium
Deactivation
Activity Recovery
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
37
46
10.30492/ijcce.2005.8106
8106
Application of Genetic Algorithm in Kinetic Modeling and Reaction Mechanism Studies
Shohreh Fatemi
1
Mohammad Masoori
2
Ramin Bozorgmehry Boozarjomehry
3
Department of Chemical Engineering, University of Tehran, I.R. IRAN
Department of Chemical Engineering, University of Tehran, I.R. IRAN
Department of Chemical & Petroleum Engineering, Sharif University of Technology, I.R. IRAN
This study is focused on the development of a systematic computational approach which implements Genetic Algorithm (GA) to find the optimal rigorous kinetic models.A general Kinetic model for hydrogenolysis of dibenzothiophene (DBT) based on Langmuir-Hinshelwood type has been obtained from open literature. This model consists of eight continuous parameters(e.g., Arrhenus and Van't Hoff parameters) and six discrete parameters representing the order of the reaction with respect to each concentration.The optimal value of these parameters have been obtained based on Genetic Algorithm. Furthermore, the best type of Genetic operators and their corresponding parameters for this type of problems have been obtained based on a comprehensive study of the effect of these parameters on the efficiency of the Genetic Algorithm.The study shows that the optimum parameters corresponding to Genetic Algorithms depends on the type of operators used in GA. Due to flexibility and generality of Genetic Algorithms, it seems that GA is a useful technique with lots of potentials in determination of optimum kinetic model corresponding to a set of complex reactions.
https://ijcce.ac.ir/article_8106_ebd5840eba0ffc66f9178521ecb35c52.pdf
genetic algorithm
kinetic model
Optimization
Hydrogenolysis of DBT
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
47
52
10.30492/ijcce.2005.8107
8107
Selective Cloud Point Extraction and Preconcentration of Copper by the Use of Dithizone as a Complexing Agent
Jamshid Manzoori
manzoori@tabrizu.ac.ir
1
Ghasem Karim Nezhad
2
Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, I.R. IRAN
Department of Chemistry, University of Payam Noor, Khoy, I.R. IRAN
The aim of this work was to develop a selective cloud point extraction method for the separation and preconcentration of copper(II) prior to spectrophotometric determination. For this purpose dithizone was used as a complexing agent and the experimental solution was acidified with sulfuric acid. Triton X-114 was used as a surfactant and after phase separation, based on the cloud point of the mixture, the rich phase was diduted with tetrahydrofuran (THF) and the enriched analyte determined by spectrophotometric analysis. The chemical and thermodynamic variables affecting the complexation and phase separation were optimized. Calibration plot of absorbance vs. concentration was linear within the range of 15-250 ng ml -1 Cu( II ) the limit of detection being 4.6 ng ml -1. The proposed procedure was successfully applied to the determination of copper in liver samples.
https://ijcce.ac.ir/article_8107_1211b8e8759f39241f1346c4850545be.pdf
Cloud point extraction
Spectrophotometry
copper
Dithizone
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
53
61
10.30492/ijcce.2005.8108
8108
The Use of Fundamental Color Stimulus to Improve the Performance of Artificial Neural Network Color Match Prediction Systems
Farhad Ameri
1
Siamak Moradian
2
Mohammad Amani Tehran
amani@aut.ac.ir
3
Karim Faez
4
Department of Polymer and Color Engineering, Amirkabir University of Technology, I.R. IRAN
Department of Polymer and Color Engineering, Amirkabir University of Technology, I.R. IRAN
Department of Textile Engineering, Amirkabir University of Technology, I.R. IRAN
Department of Electrical and Electronic Engineering, Amirkabir University of Technology, I.R. IRAN
In the present investigation attempts were made for the first time to use the fundamental color stimulus as the input for a fixed optimized neural network match prediction system. Four sets of data having different origins (i.e. different substrate, different colorant sets and different dyeing procedures) were used to train and test the performance of the network. The results showed that the use of fundamental color stimulus greatly reduces the errors as depicted by the MSE and D Cave data and improves the performance of the neural network prediction system. Additionally the use of fundamental color stimulus makes provisions for predicting the concentrations of one data set whilst being trained by a second data set of completely different origin.
https://ijcce.ac.ir/article_8108_da2f6ec183a6d2de2e82574d2aa88374.pdf
Color match prediction
Neural Networks
Fundamental color stimulus
Matrix R
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
63
71
10.30492/ijcce.2005.8109
8109
Synergetic Effects of Plasma, Temperature and Diluant on Nonoxidative Conversion of Methane to C2+ Hydrocarbons in a Dielectric Barrier Discharge Reactor
Mohammad Sadegh Haji Tarverdi
1
Yadollah Mortazavi
mortazav@ut.ac.ir
2
Abbas Ali Khodadadi
3
Shamsoddin Mohajerzadeh
4
Catalysis and Reaction Engineering Laboratory, Department of Chemical Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, I.R. IRAN
Catalysis and Reaction Engineering Laboratory, Department of Chemical Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, I.R. IRAN
Catalysis and Reaction Engineering Laboratory, Department of Chemical Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, I.R. IRAN
Department of Electrical & Computer Engineering, University of Tehran, P.O. Box 11365-4563, Tehran, I.R. IRAN
Noncatalytic and nonoxidative conversion of methane in a dielectric barrier discharge (DBD) reactor is examined at different temperatures, gas residence times and input powers. In addition, the ratio of methane to helium as a diluant, is changed in the range of 0.6 to 1.8. Results show significant synergetic effects of plasma, temperature and helium on the methane conversion and C2+ selectivities. C2 hydrocarbons are the main products (more than 70%) of the process, however, minor amounts of heavier hydrocarbons up to C8 are formed. At an input power of 230W and gas residence time of 6 sec, when the temperature increases from 100 to 200oC, the methane conversion enhances by 33%. In the temperature of 100-350oC, the methane conversion passes through a maximum at CH4 /He ratio of 1.0, at which the highest effect of the temperature is observed. In addition, at 350oC, when the input power increases from 140 to 230W, the CH4 conversion enhances from 20.3 to 27.0%. As the temperature increases from 100 to 350oC, the selectivity of ethane decreases from 81.5 to 73.0%, while the selectivities of ethylene and acetylene enhances by about 40% and 270%, respectively. The frequency of effective collisions among the reactants, excited helium (He*), and free electrons (e-) seems to increase with temperature, that in turn leads to higher methane conversions and changes in products selectivities.
https://ijcce.ac.ir/article_8109_14e72ff93ca7a7b6597103e680457518.pdf
Dielectric barrier discharge
synergy
Plasma conversion
Nonoxidative
Methane
C2+ hydrocarbons
Diluant
eng
Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR
Iranian Journal of Chemistry and Chemical Engineering
1021-9986
2005-12-01
24
4
73
78
10.30492/ijcce.2005.8110
8110
X-ray Diffraction and SEM Studies on the Effect of Temperature on the Formation of Main Phase Sr2MgSi2O7 Using a Wet and Dry Method for its Preparation
Ali Asghar Sabbagh Alvani
sabbagh_alvani@cic.aut.ac.ir
1
Ali Asghar Sarabi
2
Fathollah Moztarzadeh
3
Mohammad Rabie
4
Mohammad Javad Kamali
5
Department of Polymer Engineering, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, I.R. IRAN
Department of Polymer Engineering, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, I.R. IRAN
Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, I.R. IRAN
Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, I.R. IRAN
Department of Chemical Engineering, Iran University of Science and Technology, Tehran, I.R. IRAN
A pure Silicate host namely Sr2MgSi2O7 as a support for a long-lasting afterglow when dopped with rare-earth elements was sought after. To this end the process of obtaining firing temperatures of the above mentioned phase in normal condition was carried out using suggested wet and dry methods. The degree of purity obtained in these preparatory methods as well as the different firing temperatures were studied by the aid of SEM and XRD techniques. It was found that for the wet method there exists a temperature beyond which the amount of impurity remained constant. There also existed a temperature at which both the wet and dry methods gave the same amount of impurity. Beyond this temperature the wet method would be preferred.
https://ijcce.ac.ir/article_8110_353091d62f9702f228dbcac6e4e00226.pdf
Silicate host
Main phase
Firing temperature
Wet and dry methods