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Central composite design for the optimization of removal of the azo dye, Methyl Red, from waste water using Fenton reaction
, Pages 57-68 Mahsa Azami Morteza Bahram and Sirous Nouri PDF (321 K) |
Abstract: In this study the degradation of an azo dye, Methyl Red, which is used in textile industry, using Fenton reaction was studied and optimized by a chemometrics method. Fenton oxidation is one of the Advanced Oxidation Processes (AOPs), in which hydroxyl radicals are generated from Fenton’s reagents (Fe2+, H2O2). The effects of various experimental parameters in this reaction were investigated using Central Composite Design (CCD) method. The experimental design was done at five levels of operating parameters. 28 experiments, with 4 factors and 5 levels for each factor were designed. These factors (or variables) include [Fe2+], [H2O2], [oxalate] and the reaction time. A full-quadratic polynomial equation between the percentage of dye degradation (as the response) and the studied parameters was established. After removing the non-significant terms from the model, response surface method was used to obtain the optimum conditions. The optimum ranges of variables were: 0.1 - 0.4 mM for [Fe2+], 13.5-22 mM for [H2O2], 1.5-2 mM for [Oxalate], and 115-125 min for the reaction time. Also the results of extra experiments showed that these optimized values can be used for real samples and yield to high values for the response. DOI: 10.5267/j.ccl.2013.03.003 Keywords: Design of experiments; Methyl red; Degradation; Fenton reaction |
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Model based multi-wavelength spectrophotometric method for calculation of formation constants of phenanthrenequinone thiosemicarbazone complexes with some metallic cations
, Pages 69-76 Naser Samadi, Mina Salamati and Abdolhossein Naseri PDF (321 K) |
Abstract: In traditional spectrophotometric determination of stability constants of complexation, it is necessary to find a wavelength at which only one of the components has absorbance without any spectroscopic interference of the other reaction components. In the present work, a simple multi-wavelength model-based method has been developed to determine stability constants for complexation reaction regardless of the spectra overlapping of components. Also, pure spectra and concentration profiles of all components are extracted using multi-wavelength model based method. In the present work spectrophotometric titration of several cationic metal ions with new synthetic ligand were studied in order to calculate the formation constant(s). In order to estimate the formation constants a chemometrics method, model based analysis was applied. DOI: 10.5267/j.ccl.2013.03.002 Keywords: Complex formation; Hard-modeling; Multi-wavelength; Spectrophotometry |
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The removal of 2,4-dichlorophenol under visible light irradiation by silver indium sulfide nanoparticles synthesized by microwave
, Pages 77-84 Azadeh Tadjarodi, Amir Hossein, Cheshme khavar and Mina Imani PDF (321 K) |
Abstract: Silver indium sulfide (AgInS2) nanoparticles were synthesized by microwave method. These nanopartricles were characterized by FT-IR, XRD, DRS, SEM and TEM techniques. The band gap energy of 1.96 eV was determined by UV-Vis diffuse reflection spectrum (DRS). The photocatalytic activity was studied by photodegradation reaction of 2,4-dichlorophenol (2,4-DCP) under visible light irradiation. The influence of initial concentration, initial solution pH on the degradation percentage of 2,4-DCP and also, the kinetics of photodegradation were investigated. The removal efficiency up to 95% proved the superior capability of AgInS2 (AIS) nanoparticles for water purification. DOI: 10.5267/j.ccl.2013.03.001 Keywords: Pyrroles; Pyridazines; Ultrasound; Multi-component reactions; Green chemistry |
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Ultrasound-assisted green synthesis of pyrroles and pyridazines in water via three-component condensation reactions of arylglyoxals
, Pages 85-92 Bagher Eftekhari-Sis and Saleh Vahdati-Khajeh PDF (321 K) |
Abstract: A green and efficient method for the preparation of 5-aryl-4-hydroxy-2-methyl-1H-pyrrole-3-carboxylic acid esters and 6-aryl-3-methylpyridazine-4-carboxylic acid esters via three-component reaction of arylglyoxal hydrates with β-dicarbonyl compounds in the presence of ammonium acetate and hydrazine hydrate using water as solvent under ultrasonic irradiation was reported. The reactions proceeded rapidly and afforded the corresponding pyrroles and pyridazines in good to high yields in very short reaction time. DOI: 10.5267/j.ccl.2013.02.002 Keywords: Pyrroles; Pyridazines; Ultrasound; Multi-component reactions; Green chemistry |
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Structural effects of different NH-acids and dialkyl acetylenedicarboxylates on the kinetic parameters of stable phosphorus ylids: a mechanistic investigation
, Pages 93-104 Mohammad Zakarianejad Sayyed Mostafa Habibi-Khorassani Batoul Makiabadi and Aboozar Taheri PDF (321 K) |
Abstract: Kinetic studies were made of the reactions between triphenylphosphine 1 and dialkyl acetylenedicarboxylates 2, in the presence of NH-acids, such as benzotriazole, 5-methylbenzotriazole or 5-chlorobenzotriazole 3 (as a protic/nucleophilic reagent). To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometry. Useful information was obtained from studies of the effect of solvent, structure of reactants (dialkyl acetylenedicarboxylates and NH-acids) and also concentration of reactants on the reaction rates. First and third steps (k2, k3) of all reactions were recognized as a rate determining and fast steps, respectively. Proposed mechanism was confirmed on the basis of experimental data. DOI: 10.5267/j.ccl.2013.02.001 Keywords: Stable phosphorus ylides; Dialkyl acetylenedicarboxylates; NH-acid; Heterocyclic compounds; Kinetic studies |
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Synthesis of quinoxalines in the presence of heteropoly acids
, Pages 105-108 Fatemeh Hakimia and Bi Bi Fatemeh Mirjalili PDF (321 K) |
Abstract: Efficient synthesis of quinoxaline derivatives from the reaction of α-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA) such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced. DOI: 10.5267/j.ccl.2013.01.001 Keywords: Quinoxalines, 1,2-Diketones, o-Phenylenediamines, Keggin-type Heteropolyacids |
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