Search for: purification
Total 129 records
Simulation of water purification using magnetically ultra-responsive micro- and nanoscavengers, Article Journal of Water Process Engineering ; Volume 24 , 2018 , Pages 63-73 ; 22147144 (ISSN) ; Moosavi, A ; Kazemzadeh Hannani, S ; Sharif University of Technology
Elsevier Ltd 2018
Access to clean water is one of the challenges of the 21st century. Thus water purification is inevitable. One method of water treatment is purification by magnetic particles in the presence of magnetic field. The contaminants are attached to the magnetic particles and then by applying a magnetic field, magnetic particles and, thus, the pollutants can be collected. For the optimal design of a water treatment system, the effect of important parameters in the design, such as magnetic fields, particle size, and Reynolds number are determined numerically by modeling and simulating the water treatment process. Two methods are used to create the magnetic field: permanent magnet and coils. It is...
Synthesis and Recognition of a Nano- Composite Ceramic Membrane for Hydrogen Purification, M.Sc. Thesis Sharif University of Technology ; Safe Kordi, Ali Akbar
In this work, we have tried to synthesize, recognize and evaluate the performance of a composite ceramic membrane to purify hydrogen and obtain high H2 separation values from other gases such as methane, carbon dioxide and nitrogen at high operating temperatures (837- 1073 K). The membrane was prepared by modification of a tubular alpha- alumina support with a series of gamma- alumina layers using sol- gel method. The membrane was then covered with a Nano-composite silica- alumina layer using CVD method. The thickness of this layer is estimated to be around 80- 100 nm and with a completely dense structure. EDX, XRD, DLS, BET and mercury porosietery analysis plus SEM and FESEM images were...
Experimental study and thermodynamic modeling for purification of extracted algal lipids using an organic/aqueous two-phase system, Article RSC Advances ; Volume 5, Issue 2 , 2015 , Pages 1153-1160 ; 20462069 (ISSN) ; Pazuki, G ; Vossoughi, M ; Sharif University of Technology
Royal Society of Chemistry 2015
The extraction and purification of lipids from the microalgae Chlorella vulgaris have been investigated. First, a mixture of hexane and ethanol was used to extract lipids from the algal biomass. Ultrasonication was employed to disrupt the cell wall and increase the extraction performance. Under these conditions, over 90% of the fatty acids in the biomass were extracted. Second, a biphasic system was formed by adding water and hexane to the extracted crude oil. In this way, fatty acids were mainly distributed in the organic phase (mostly hexane and ethanol) while most of the contaminants remained in the aqueous phase (mostly water and ethanol). Equilibrium distribution data between the phases...
Rule of thumb for gas permeation systems' calculations, Article Petroleum and Coal ; Volume 57, Issue 4 , 2015 , Pages 360-365 ; 13377027 (ISSN) ; Mivechian, A ; Sharif University of Technology
Slovnaft VURUP a.s 2015
In gas purification using polymeric membrane systems, different parameters affect on product specification. In these systems, pressure ratio, stage-cut, membrane selectivity and feed purity are important parameters which changing in these parameters results in a different product specification. Existence of a mathematical correlation between these parameters can be helpful and it gives a view that shows how can approach to products with desired specification. In present study, a correlation between effective parameters has been developed. This dimensionless mathematical model shows how product purity and recovery are influenced by membrane selectivity (DR; from 2 to 125) and feed purity in...
Practical techniques for improving the performance of polymeric membranes and processes for protein separation and purification, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 37, Issue 2 , February , 2018 , Pages 1-23 ; 10219986 (ISSN) ; Minooei, F ; Hosseini, S. S ; Sharif University of Technology
Iranian Journal of Chemistry and Chemical Engineering 2018
Protein separation and purification technologies play an essential role in various industries including but not limited to pharmaceuticals, dairy as well as the food sector. Accordingly, a wide variety of techniques such as chromatography and electrophoresis have been developed and utilized extensively over the years for this purpose. Despite their widespread acceptance, conventional techniques still suffer from major limitations and complexities such as short lifetime, low productivity, high-pressure drop and difficulty in scale-up among others. Membrane separation processes have received significant attention in recent years as a promising alternative that can potentially overcome the...
Isolation of penicillin G acylase from Escherichia coli ATCC 11105 by physical and chemical treatments, Article Biochemical Engineering Journal ; Volume 8, Issue 3 , 2001 , Pages 223-227 ; 1369703X (ISSN) ; Ardjmand, M ; Fazelinia, H ; Zakeri, A ; Sharif University of Technology
Different techniques including toluene-ethanol, guanidine hydrochloride, guanidine hydrochloride-EDTA, lysozyme, lysozyme-EDTA and sonication treatments were used to extract penicillin G acylase from Escherichia coli ATCC 11105 cells. The obtained results show that penicillin G acylase extraction by guanidine-EDTA treatment is more specific in comparison to the other applied methods. The maximum specific activity of the enzyme (5.61 U/mg), i.e. the maximum purification was found when 1 M guanidine + 100 mM EDTA solution was used for penicillin G acylase extraction at culture condition including 0.50% (w/v) yeast extract as carbon source. In such a condition more than 95% of the enzyme was...
Quantitative risk assessment for accidental release of ethylene oxide from purification column of an ethylene oxide production unit, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Hashemi, V ; Rashtchian, D ; Sharif University of Technology
This paper outlines a quantitative risk assessment for an 110,000 ton/day ethylene oxide production plant in Iran. After a complete and detailed hazard identification study, done by HAZOP method, the purification column was found to be one of the most hazardous sections in this plant. As ethylene oxide with high concentration and inventory is present there. Fault tree analysis (FTA) technique has been used to identify the basic events responsible for top event occurrence and also calculation of top event frequency of occurrence. Human error has been calculated numerically and probability of human error has been estimated. Failure rate data were collected referring to several sources and...
Separation and Purification of Conjugated Linoleic Acid Isomers from Vegetable Oils, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran
Conjugated linoleic acid (CLA), a mixture of positional and geometrical isomers of linoleic acid with conjugated double bonds, has gained considerable attention because of its anticarcinogenic and obesity treatment properties. The most biologically active CLA isomers are 9c, 11t-18:2 and 10t, 12c-18:2. The aim of this study is to separate and purify the two essential isomers via enzymatic method by Candida rugosa lipase and chemical method by urea crystallization and also optimization of reaction conditions in order to better separation. For enzymatic purification, L-menthol and Lauryl alcohol were used separately. Optimization of reaction conditions by enzyme content, time and the ratio of...
Solvent-free synthesis of 3-benzylpyrano[3,2-c]pyran/chromene-2,5-diones via tandem reaction of 4-hydroxy-6-methyl-pyran-2-one and 4-hydroxycoumarin with Baylis-Hillman adduct acetates, Article Scientia Iranica ; Vol. 21, issue. 3 , 2014 , p. 735-741 ; 1026-3098 ; 2345-3605 ; Koushki Foroushani, B ; Lotfi Kalahroodi, E ; Sharif University of Technology
4-hydroxycoumarin 2a and 4-hydroxy-6-methyl-pyran-2-one 2b were applied in a one-pot reaction with Baylis-Hillman adduct acetates 1 to form novel 3-benzylpyrano [3, 2-c] pyran-2, 5-diones 3 in high yields (70-85%). The synthesized framework is available in many biologically active moieties. The reaction was carried out under different conditions to achieve optimum conditions. The results indicated that Et3N, as a base under solvent-free conditions, was optimum. The reaction procedure and purification method are mild and straightforward
Hydrogen distribution in refinery with non-linear programming, Article International Journal of Engineering, Transactions B: Applications ; Volume 18, Issue 2 , 2005 , Pages 165-176 ; 1728-144X (ISSN) ; Kashi, E ; Rashtchian, D ; Sharif University of Technology
Materials and Energy Research Center 2005
Growth of the world population, increasing demand for fossil fuel consumption and consequently increasing threat of global warming, has extended the need for production and use of clean fuels and normal hydrogen is an important utility in the production of clean fuels. In this paper, a mathematical optimization method is applied which is based on non-linear programming of superstructure for minimizing the consumption of hydrogen. The method considers all the pressure constraints and is suited for revamping industrial systems. The optimum placement of new equipments like purification unit has been also considered. It is tried to verify the method adopted, in addition, an industrial case study...
Hydrogen management in refineries, Article Petroleum and Coal ; Volume 54, Issue 4 , 2012 , Pages 357-368 ; 13377027 (ISSN) ; Sharif University of Technology
Environmental restrictions, new transportation fuel specifications, and increased processing of heavier more-sour curds are leading substantial increases in refinery hydrogen consumption for hydrodesulfurisation, aromatic and olefin saturation and improvement of product quality and reduces in refinery hydrogen production from catalytic reformers as a by-product. Therefore above factors make hydrogen management, a critical issue. Generating, recovering and purchasing of hydrogen have significant impact on refinery operating costs. More importantly, overall refinery operations, may be constrained by the availability of hydrogen. Primary consideration, however, should be given to the recovery...
Turnip (brassica rapa) peroxidase: Purification and characterization, Article Industrial and Engineering Chemistry Research ; Volume 48, Issue 23 , Volume 48, Issue 23 , 2009 , Pages 10614-10618 ; 08885885 (ISSN) ; Ghaemmaghami, F ; Alemzadeh, I ; Sharif University of Technology
Partial purification of plant peroxidase from turnip (Brassica rapa) was optimized. Aqueous two phase system and precipitation by ammonium sulfate (as two parallel purification methods) were used. Polyethylene glycol/ammonium sulfate/NaCl (25:7:3%, w/v) system followed by gel-filtration chromatography gave a purification factor of about 36 fold. On the other hand, ammonium sulfate precipitation (60-80% deg) followed by gel filtration gave only about 13 purification fold. Hence, the aqueous two-phase system was more efficient and useful method as a primary purification step since it was less laborious, less time-consuming, and led to more purification factor. The partially purified turnip...
The Modeling of Hydrogen Purification and Carbon Dioxide Capture by two Dimensional Porous Membranes Using Molecular Dynamicssimulations, M.Sc. Thesis Sharif University of Technology ; Tafazzoli, Mohsen
Carbon dioxide is one of the most significant greenhouse gases in biocycle. This gas makes the equilibrium temperature by absorbing IR radiations on the earth. It is the reason that prevent the earth from freezing. Increasing CO2 emissions in atmosphere, makes problems such as global warming. According to the Kyoto Protocol, all the countries attended to this protocol, must decrease greenhouse gases emissions. Although H2 fuel is one of the best alternative fuel against fossil fuels, the most important industrial process (steam-methane reforming) produce CO2 as by-product. Thus, gas separation has a prominent role in industrial processes such as CO2 capture and H2 purification.Today, gas...
Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes, Article Journal of Industrial and Engineering Chemistry ; 2015 ; ISSN: 1226086X ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl2 and Pd(OAc)2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.% of palladium on activated carbon)...
Surveying the jagorood river's self-purification, Article 6th International Conference on Environmental Informatics, ISEIS 2007 ; 21-23 November , 2014 ; Mirzai, M ; Sajadi, S. A. A ; Alamolhoda, A. A ; Sharif University of Technology
the development and enlargement of city structure has caused the environmental problems on watershed of Latian dam which is one of the drinking water resourses of Tehran. The enlargement of Lavasan town and existence of an army garrison that it's effluents of treatment plant discharge to this river necessitate a water quality surveillance in entrance area of the dam. The present research includes the survey of this river's self-purification in the mentioned-above area. Numerical analysis is used in different methods to explain self- purification. Frist, we have the numerical analysis and analytical methods for a known sample in order to determine the accuracy and deviation between two...
Hydro-purification of crude terephthalic acid using palladium catalyst supported on multi-wall carbon nanotubes, Article Journal of Industrial and Engineering Chemistry ; Volume 28 , August , 2015 , Pages 202-210 ; 1226086X (ISSN) ; Khorasheh, F ; Rashidi, A. M ; Safekordi, A. A ; Sharif University of Technology
Korean Society of Industrial Engineering Chemistry 2015
Palladium catalysts supported on functionalized multi-wall carbon nanotubes were synthesized for hydro-purification of crude terephthalic acid containing 2100ppm 4-carboxybenzaldehyde (4-CBA) as impurity. PdCl
2 and Pd(OAc) 2 were used as precursors. Palladium loadings were 0.05 to 0.6wt.% with catalysts reduced at 200 to 400°C. Catalysts prepared from both precursors with least 0.3wt.% palladium resulted in 99%+ removal of 4-CBA. The most desired selectivity was obtained for the catalyst with PdCl 2 as precursor, reduction temperature of 300°C, and palladium loading of 0.3wt.%. This catalyst had slightly better performance than the commercial catalyst (0.5wt.%...
Comparison of synthesis and purification of carbon nanotubes by thermal chemical vapor deposition on the nickel-based catalysts: NiSio2 and 304-type stainless steel, Article Journal of Applied Sciences ; Volume 10, Issue 9 , 2010 , Pages 716-723 ; 18125654 (ISSN) ; Jafari, A ; Fekri, S ; Shafikhani, A ; Vesaghi, M ; Behzadi, G ; Sharif University of Technology
In this study by Thermal Chemical Vapor Deposition (TCVD) method, the synthesis of carbon nanotubes (CNTs) and temperature affects on the grown CNTs on the NiSio2 catalyst and 304-type stainless steel was investigated. The purification of the grown CNTs on the 304-type stainless steel was also investigated in this study. The synthesis and purification of the samples were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), termogravimetric analysis (TGA) and Raman spectroscopy. Our obtained result by SEM and TEM shows that densities of CNTs growth on the 304-type stainless steel are more than the CNTs growth on the NiSio2 catalyst and both of them have...
Swirl intensity as a control mechanism for methane purification in supersonic gas separators, Article Journal of Natural Gas Science and Engineering ; Volume 83 , 2020 ; Amini Magham, M ; Sharif University of Technology
Elsevier B.V 2020
Supersonic gas separator is proposed for methane purification. One-dimensional analysis is performed to examine the design aspects associated with the converging-diverging nozzle and the liquid separation chamber. The results indicate that at low swirl intensities, the separation chamber length is about 100 times of the nozzle throat. Increasing the swirl intensity would lower this length sharply and it will be less than 10 for swirl intensity of unity which is equivalent to a swirl angle of 45°. In addition, a sensitivity analysis of the separator performance to the inlet conditions like the temperature, pressure, and composition of the mixture is carried out. It is observed that increasing...
Hydrogel materials as an emerging platform for desalination and the production of purified water, Article Separation and Purification Reviews ; 2020 , Pages 1-20 ; Ghannadi Maragheh, M ; Torab Mostaedi, M ; Torkaman, R ; Asadollahzadeh, M ; Sharif University of Technology
Taylor and Francis Inc 2020
Water is the most abundant liquid on Earth, but only 2.5% of worldwide water are fresh. It is impossible to ignore the importance of water in almost every process on Earth, from the smallest bacteria life to the formation of the continents. Today, efforts for the desalination of seawater and brackish water are critical to produce drinking water. In recent years, a novel material: hydrogel, was considered in desalination processes. Interesting hydrogel applications were proposed for forward osmosis desalination, solar still, electrodialysis, and capacitive desalination. Simple and inexpensive desalination ways for drinking water production are needed. Hydrogel compounds are one of the leading...
Investigation of Nano-Semiconductors for Decontamination of Pollutants under Solar Light, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad ; Vossoughi, Manouchehr ; Feilizadeh, Mehrzad
Photocatalytic degradation is one of the developing modern and effective methods for decontamination of hazardous pollutants of chemical industrial wastewater. For this purpose, in this research, the efficiency of the photocatalytic process in degradation of Cortisone Acetate is investigated under solar light irradiation, and the effect of two useful oxidants, potassium persulfate (PDS) and potassium proxy mono sulfate (PMS), on the degradation efficiency is examined. At first, the single effect of these two oxidants, and then their interaction effects with the photocatalyst (TiO2-P25) and solution pH by analytical analysis and with the help of Response Surface Methodology (RSM) and...