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Statistical analysis for enzymatic decolorization of acid orange 7 by Coprinus cinereus peroxidase
, Article International Biodeterioration and Biodegradation ; Volume 64, Issue 3 , 2010 , Pages 245-252 ; 09648305 (ISSN) ; Kariminia, H. R ; Sharif University of Technology
2010
Abstract
Enzymatic decolorization of the monoazo dye, acid orange 7 (AO7) by the fungal peroxidase from Coprinus cinereus NBRC 30628 is a complex system, which is greatly affected by temperature, pH, enzyme activity and the concentrations of H2O2 and dye concentration. The study of these factors and investigating the combined interactions between them by applying one-factor-at-a-time (OFAT) method and two other statistical methods including 2-factorial method and response surface methodology (RSM) were aimed in this work. Through OFAT analysis the optimized conditions were a temperature of 25 °C, pH 9.0 with H2O2 concentration of about 3.9 mM and AO7 concentration of 40 mg/l. A complete...
Catalytic wet peroxide oxidation of phenol in a new two-impinging-jets reactor
, Article Industrial and Engineering Chemistry Research ; Volume 48, Issue 23 , 2009 , Pages 10619-10626 ; 08885885 (ISSN) ; Ebrahimi, A. A ; Sharif University of Technology
Abstract
The catalytic wet peroxide oxidation (CWPO) of phenol with activated carbon (AC) as the catalyst has been successfully tested in a novel type of two-impinging-jets reactor (TIJR). The TIJR is characterized by a high-intensity reaction chamber, which is separated by a perforated plate from other parts of the reactor. The perforated plate was used as a filter to keep the catalyst particles within the reaction chamber. The influences of various operating and design parameters such as jet Reynolds number, feed flow rate, internozzle distance, and the jet diameter on the performance capability of the TIJR were investigated. As a result of the impinging process, turbulence, complex trajectory of...
Oxidative desulfurization of simulated light fuel oil and untreated kerosene
, Article Fuel Processing Technology ; Volume 90, Issue 3 , 2009 , Pages 435-445 ; 03783820 (ISSN) ; Kiaei, Z ; Sobati, M.A ; Sharif University of Technology
2009
Abstract
An experimental investigation was conducted on the oxidative desulfurization of model sulfur compounds such as dibenzothiophene and benzothiophene in toluene as a simulated light fuel oil with a mixture of hydrogen peroxide as the oxidant and various acids as the catalyst. The influences of various parameters including reaction temperature (T), acid to sulfur molar ratio (Acid/S), oxidant to sulfur molar ratio (O/S), type of acid, and the presence of sodium tungstate and commercial activated carbon as a co-catalyst on the fractional conversion of the model sulfur compounds were investigated. The experimental data obtained were used to determine the reaction rate constant of the model sulfur...
Oxidative desulfurization of Non-hydrotreated kerosene using hydrogen peroxide and acetic acid
, Article Chinese Journal of Chemical Engineering ; Volume 17, Issue 5 , 2009 , Pages 869-874 ; 10049541 (ISSN) ; Sobati, M. A ; Nazem, M. A ; Sharif University of Technology
2009
Abstract
The oxidative desulfurization of a real refinery feedstock (i.e., non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied. The influences of various operating parameters including reaction temperature (T), acid to sulfur molar ratio (nacid/nS), and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated. The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal. Moreover, there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS8 and 23 for the reaction temperatures of 25...
Kinetics investigation of the photocatalytic degradation of acid blue 92 in aqueous solution using nanocrystalline TiO2 prepared in an ionic liquid
, Article Progress in Reaction Kinetics and Mechanism ; Volume 34, Issue 1 , 2009 , Pages 55-76 ; 14686783 (ISSN) ; Rahimnejad, S ; Rahman Setayesh, S ; Hosseini, M ; Gholami, M. R ; Sharif University of Technology
2009
Abstract
TiO2 nanoparticles were prepared by the sol - gel process using 2-hydroxylethy- lammonium formate as an ionic liquid. Nanoparticles were crystallized at various temperatures (300-700°C). The products were characterized using X-ray diffraction (XRD), nitrogen adsorption - desorption isotherms and scanning electron microscopy (SEM) techniques. It was found that the resulting TiO2 nanoparticles had good thermal stability either to resist collapse or the anatase-to-rutile phase transformation during heat treatment. The photocatalytic activity of the nanocrystalline TiO2 was evaluated by the degradation of Acid Blue 92 (AB92) which is commonly used as a textile dye. The results showed that the...
Phenols removal by immobilized horseradish peroxidase
, Article Journal of Hazardous Materials ; Volume 166, Issue 2-3 , 2009 , Pages 1082-1086 ; 03043894 (ISSN) ; Nejati, S ; Sharif University of Technology
2009
Abstract
Application of immobilized horseradish peroxidase (HRP) in porous calcium alginate (ca-alginate) for the purpose of phenol removal is reported. The optimal conditions for immobilization of HRP in ca-alginate were identified. Gelation (encapsulation) was optimized at 1.0% (w/v) sodium alginate in the presence of 5.5% (w/v) of calcium chloride. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. Increasing initial phenol concentration results in a decrease in % conversion. The highest conversion belongs to phenol concentration of 2 mM. Investigation into time course of phenol removal for both encapsulated and free enzymes showed...
Synthesis, X-ray structure and study of a mixed ligand iron(III) complex with tridentate Schiff base as a homogeneous catalyst in the efficient oxidation of sulfides
, Article Inorganic Chemistry Communications ; Volume 12, Issue 6 , 2009 , Pages 476-480 ; 13877003 (ISSN) ; Tahsini, L ; Latifi, R ; Amani, V ; Ellern, A ; Keith Woo, L ; Sharif University of Technology
2009
Abstract
A mononuclear mixed ligand complex of iron, [FeIII(N-OPh-sal)(acac)EtOH], where Hacac and N-HOPh-Hsal denote acetylacetone and N-hydroxyphenyl-salicylideneamine, respectively, has been synthesized and characterized by elemental analysis, spectral studies and X-ray crystallography. The catalytic system containing this complex and urea hydrogen peroxide as oxidizing agent was used to selectively oxidize a range of sulfides to the corresponding sulfoxides in good yields under mild conditions. The electronic spectra of the catalytic system were applied to explore reactivity and stability of the catalyst during sulfide oxidation reactions and to examine the nature of active species, as well. ©...
Catalytic wet peroxide oxidation of phenol : H2O2 gradual addition study
, Article 2008 AIChE Annual Meeting, AIChE 100, Philadelphia, PA, 16 November 2008 through 21 November 2008 ; November , 2008 ; 9780816910502 (ISBN) ; Ebrahimi, A. A ; Shahalami, S ; Sharif University of Technology
2008
Catalytic oxidation of sulfides to sulfoxide using manganese(III) complexes with bidentate O,N-donor oxazoline ligand and UHP oxidizing agent
, Article Catalysis Communications ; Volume 10, Issue 2 , 2008 , Pages 196-200 ; 15667367 (ISSN) ; Latifi, R ; Tahsini, L ; Amini, M ; Sharif University of Technology
2008
Abstract
The efficient catalytic systems were investigated for the oxidation of various sulfide by manganese(III)-oxazoline complexes, [Mn(phox)2(MeOH)2]ClO4 and Mn(phox)3 (Hphox = 2-(2′-hydroxyphenyl)oxazoline). These complexes were found efficient catalysts for the oxidation of sulfides with urea hydrogen peroxide (UHP) in short reaction times (5 min) and under mild condition. Sulfoxides were obtained as the main products together with variable amounts of sulfones. The efficiency of the catalytic system was strongly influenced by the nature of solvents and axial ligands so the best yields were achieved in a mixture of methanol: dichloromethane and in the presence of imidazole as co-catalyst. © 2008...
Efficient oxidation of olefins and sulfides catalyzed by manganese(III)-tridentate Schiff base complex using UHP as oxidant
, Article Catalysis Communications ; Volume 9, Issue 7 , 2008 , Pages 1600-1606 ; 15667367 (ISSN) ; Tahsini, L ; Latifi, R ; Sharif University of Technology
2008
Abstract
Catalytic studies were performed to develop a simple oxidation system for olefins and sulfides using manganese(III)-tridentate Schiff base complex, Mn(N-OPh-sal)(acac)(EtOH) (N-HOPh-Hsal = N-hydroxyphenyl-salicyldienamine, Hacac = acetylacetone), and urea-hydrogen peroxide (UHP) as terminal oxidant. Conversions up to 90% for olefins at 0 °C and 96% for sulfides at room temperature as well as sulfoxide selectivity up to 73% were achieved in short reaction times. Also this study confirms the accelerating effect of strong π-donor axial ligands such as imidazole (ImH) on the oxidation reactions. © 2008 Elsevier B.V. All rights reserved
Density functional theory studies of oxygen and carbonate binding to a dicopper patellamide complex
, Article Journal of Inorganic Biochemistry ; Volume 102, Issue 12 , 2008 , Pages 2171-2178 ; 01620134 (ISSN) ; Bagherzadeh, M ; Milne, B. F ; Jaspars, M ; de Visser, S. P ; Sharif University of Technology
2008
Abstract
In this work we present results of density functional theory (DFT) calculations on dicopper patellamides and their affinity for molecular oxygen and carbonate. Patellamides are cyclic octapeptides that are produced by a cyanobacterium, and may show promise as therapeutics. Thus, carbonate binding to a dicopper patellamide center gives a stable cyclic octapeptide with a twist of almost 90°. The system exists in close-lying open-shell singlet and triplet spin states with two unpaired electrons in orthogonal σ* orbitals on each metal center. Subsequently, we replaced carbonate with dioxygen and found a stable Cu2(μ-O)2 diamond shaped patellamide core. In this structure the original dioxygen...
A green and efficient deoximation using H2O2 catalyzed by montmorillonite-K10 supported CoCl2
, Article Chinese Chemical Letters ; Volume 18, Issue 12 , December , 2007 , Pages 1451-1454 ; 10018417 (ISSN) ; Najafi, G. R ; Hashemi, M. M ; Sharif University of Technology
2007
Abstract
Oximes were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant, H2O2 catalyzed by montmorillonite K-10 supported cobalt(II) chloride. © 2007 Ali Ezabadi
Transition metal free oxidation of alcohols to carbonyl compounds using hydrogen peroxide catalyzed with LiCl on montmorillonite K10
, Article Acta Chimica Slovenica ; Volume 54, Issue 3 , 2007 , Pages 635-637 ; 13180207 (ISSN) ; Khalili, B ; Abdollahifar, A ; Hashemi, M. M ; Sharif University of Technology
2007
Abstract
Alcohols have been successfully converted into their corresponding carbonyl compounds using hydrogen peroxide catalyzed by lithium chloride on montmorillonite K10. Clay supported lithium chloride can be recovered after using as catalyst for oxidation of alcohols. The future runs according to this procedure showed no considerable decrease in the reaction yield and catalyst effect
Optimization of peroxidase-catalyzed oxidative coupling process for phenol removal from wastewater using response surface methodology
, Article Environmental Science and Technology ; Volume 41, Issue 20 , 2007 , Pages 7073-7079 ; 0013936X (ISSN) ; Torabi, S. F ; Ranaei Siadat, S. O ; Jalali Heravi, M ; Ghaemi, N ; Khajeh, K ; Sharif University of Technology
2007
Abstract
Hydroxylated aromatic compounds (HACs) are considered to be primary pollutants in a wide variety of industrial wastewaters. Horseradish peroxidase (HRP) is suitable for the removal of these toxic substances. However, development of a mathematical model and optimization of the HRP-based treatment considering the economical issues by novel methods is a necessity. In the present study, optimization of phenol removal from wastewater by horseradish peroxidase (HRP) was carried out using response surface methodology (RSM) and central composite design (CCD). As the initial experimental design, 2 4-1 half-fraction factorial design (H-FFD) is accomplished in triplicate at two levels to select the...
Catalytic activity of manganese(III)-oxazoline complexes in urea hydrogen peroxide epoxidation of olefins: The effect of axial ligands
, Article Journal of Molecular Catalysis A: Chemical ; Volume 260, Issue 1-2 , 2006 , Pages 163-169 ; 13811169 (ISSN) ; Latifi, R ; Tahsini, L ; Sharif University of Technology
2006
Abstract
The catalytic activity of two manganese(III)-oxazoline complexes [Mn(phox)2(CH3OH)2]ClO4 and Mn(phox)3 (Hphox = 2-(2′-hydroxylphenyl)oxazoline), was studied in the epoxidation of various olefins. All of epoxidation reactions were carried out in (1:1) mixture of methanol:dichloromethane at room temperature using urea hydrogen peroxide (UHP) as oxidant and imidazole as co-catalyst. The epoxide yields clearly demonstrate the influence of steric and electronic properties of olefins, the catalysts and nitrogenous bases as axial ligand. [Mn(phox)2(CH3OH)2]ClO4 catalyst with low steric properties has higher catalytic activity than Mn(phox)3. The highest epoxide yield (95%) was achieved for indene...
Extraction and processing optimization of gelatin from fish (otolithes ruber) skin
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Aminshahidi, B ; Meraj, F ; Sharif University of Technology
2006
Abstract
Gelatin is a denatured protein derived from collagen by thermohydrolysis and has a rheological property of thermo reversible transformation between sol & gel. Gelatin is one of the most important biopolymers, with widespread applications in the food, pharmaceutical, cosmetic and photographic industries. Gelatin is commercially made from skins and skeletons of bovine and porcine and mammalian gelatin has been intensively studied. However, mammalian gelatin is at risk for contamination with bovine spongiform encephalopathy and increase in demand for kosher and halal foods have created a demand for fish gelatin for food applications. Therefore, the objective of this study was to extract gelatin...
Novel oxidation of phenols to quinones by hydrogen peroxide in the presence of cobalt(II) and manganese(II) acetate
, Article Acta Chimica Slovenica ; Volume 50, Issue 3 , 2003 , Pages 569-572 ; 13180207 (ISSN) ; Ahmadibeni, Y ; Sharif University of Technology
2003
Abstract
Hydrogen peroxide readily oxidizes phenols to the corresponding quinones in the presence of cobalt(II) acetate or manganese(II) acetate as catalyst
Aromatization of Hantzsch 1,4-dihydropyridines by hydrogen peroxide in the presence of cobalt(II) acetate
, Article Monatshefte fur Chemie ; Volume 134, Issue 1 , 2003 , Pages 107-110 ; 00269247 (ISSN) ; Ahmadibeni, Y ; Ghafuri, H ; Sharif University of Technology
2003
Abstract
Hydrogen peroxide readily oxidizes Hantzsch type 1,4-dihydropyridines in the presence of cobalt(II) acetate as catalyst at room temperature. No evidence of a dealkylation process for 4-alkyl 1,4-dihydropyridines has been observed