فهرست مطالب

Iranian Journal of Chemistry and Chemical Engineering - Volume:38 Issue: 2, 2019
  • Volume:38 Issue: 2, 2019
  • تاریخ انتشار: 1398/01/12
  • تعداد عناوین: 25
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  • Mahdieh Nafar, Gholamhossein Grivani * Pages 1-8
    The acidic group (-CO2H) of MultiWall Carbon Nanotube (MWCNT) converted to acyl chloride group (-COCl) producing of MVCNT@COCl. Then the reaction of MVCNT@COCl and MoO2(acac)2 resulted in direct immobilization of the MoO2(acac)2 and the formation of MVCNT@CO(acac)MoO2(acac) catalyst. In addition, the MVCNT@COCl was esterified by NaOC2H5 and formed the esteric MVCNT@COC2H5 reagent. In a subsequent reaction of MVCNT@COC2H5 by ethylene diamine, the MVCNT@CONHCH2CH2NH2 was produced. It was reacted with MoO2(acac)2 and immobilized the MoO2(acac)2 via imine bond formation and produced the MVCNT@CONHCH2CH2N(acac)MoO2(acac) catalyst. The functionalized MVCNT reagents were characterized by FT-IR spectra and elemental analysis. The molybdenum loading on MVCNT was determined by ICP analysis. The catalytic activity of the two molybdenum immobilized catalysts (MVCNT@COMoO2(acac)2 and MVCNT@CONHCH2CH2N(acac)MoO2(acac)) was investigated in the epoxidation of cyclooctene and different reaction parameters such as solvent, oxidant, amount of catalyst and oxidant were optimized and the epoxidation of different alkenes was investigated in these optimized conditions. The obtained results showed that the supported catalysts of MVCNT@CO(acac)MoO2(acac)2 and MVCNT@CONHCH2CH2N(acac)MoO2(acac) were highly active and selective in the epoxidation of a wide range of alkenes. The reusability of the supported catalysts was also studied. The results showed that they had good reusability in the epoxidation of alkenes.
    Keywords: carbon nano tube, Immobilization, Mo, Epoxidation, alkene
  • Parisa Shaltouki, Elaheh Mohamadi, Mohammad Ali Moghaddasi, Afshin Farahbakhsh, Hooman Bahmanpour * Pages 9-19
    In order to protection, convenient release, and increase of antibacterial of capsules to the treatment of diseases, propolis nanoparticles encapsulate. Beeswax is used for covering because of its special physical and chemical properties, ineffective and inactivity and ease of mixingwith materials without any adverse reaction. In this study, nanotechnology and renewable natural compounds of beeswax were used in the process of encapsulating for protection against adverse environmental conditions. At first, propolis nanoparticles were mixed withchloroform then ammonia buffer and Tween -80 was added to it while stirring with speed rpm 300. The mixture was shocked to form the capsule. After filtration andwashing produced capsules were dried for 48 hours at room temperature. Assessment of formation and performance of the capsules was done by changing parameters such as pH, time and temperature, the loading of nanoparticles by spectrophotometry method and increasing the antimicrobial properties using microbial culture.  Also, FT-IR analysis was done to prove the physical transplant of wax and propolis. According to TEM images, the size of produced capsules was estimated in the range of 200 to 500 nm with 95% distribution percentages. Based on Taguchi testing, the optimum time, temperature and pH for the release of encapsulated nanoparticles were 10 minutes, 43ºC and 10, respectively.
    Keywords: Encapsulating, Propolis Nanoparticles, Capsule, Beeswax, Spectrophotometry
  • Majid Saghi *, Mohammad Khazaei Nejad, Ali Arasteh Pages 21-28

    In the research, spherical α-Fe2O3 NanoParticles (NPs) were synthesized through Forced Hydrolysis and Reflux Condensation (FHRC) process and were supported on the surface of silica sand by Solid-State Dispersion (SSD) method. Characterization of silica and α-Fe2O3/SiO2 catalyst was done using Fourier-Transform InfraRed (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM) images, X-Ray Diffraction (XRD) patterns and Brunauer, Emmet and Teller (BET) surface area. The supported α-Fe2O3/SiO2 nanocatalyst with the average crystallite size of 27.5 nm was used for photocatalytic removal of Methylene Blue (MB) from aqueous solutions under Ultra-Violet (UV) light.In order to optimization of effective parameters on MB degradation, the single-variable method was used. The optimal conditions were determined as pH=11, initial concentration of MB=10 ppm, and the mass of catalyst =1.0 g. Degradation efficiency in optimal conditions was 97.32%.

    Keywords: Methylene blue, SSD, FHRC, α-Fe2O3, SiO2
  • Zaid Hamid Mahmoud * Pages 29-35
    Gold doped TiO2 has been successfully synthesized via the photolysis method and is characterized by different techniques. NPs of gold doped TiO2 were utilized for the degradation of methylene blue as a material pigmentation pollutant. The substitution of Au on TiO2 surface was established via XRD, EDX, TEM, and FT-IR techniques. The TEM and SEM results appeared that the particles in the nano range and its size below 15nm. Without a catalyst, the degradation of dye under visible light in acid and nature medium gives humble results but good results at pH 11 while it gives excellent results at all conditions when using catalyst.
    Keywords: Doped, Methylene blue, nanoparticles, Photodegradation, Photolysis
  • Mohammad, Saleh Zabihi, Jahanbakhsh Raoof *, Sayed Reza Hosseini, Mahmoud Reza Sohrabi Pages 37-48
    In this work, Phosphotungstic Acid modified Carbon Paste Electrode (PWA-CPE) is used as a substrate for electro-polymerization of o-Anisidine (OA). Also, Triton X-100 (TX-100) surfactant is used as an additive for electrochemical polymerization of OA onto the PWA-CPE, which is investigated as a novel matrix for dispersion of nickel species. The prepared electrodes are characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and electrochemical methods. Growth of the poly o-Anisidine (POA) film in the absence of TX-100 and/or PWA is very poor, while it considerably increases in the presence of them. The methanol oxidation and stability of the Ni/POA (TX-100)/PWA-CPE are investigated by various electrochemical techniques. It has been shown that the poly (o-Anisidine)/Triton X-100 (POA (TX-100)) at the surface of PWA-CPE improves the catalytic efficiency of the dispersed Ni(OH)2 nanoparticles towards methanol oxidation.
    Keywords: Electro-catalysis, Methanol, Ni(OH)2 nanoparticles, Poly (o-Anisidine), Triton X-100 film, Phosphotungstic acid
  • Saeed Sahebdelfar *, Fereydoon Yaripour, Somayeh Ahmadpour, Farhad Khorasheh Pages 49-59
    The product distribution of methanol to hydrocarbons conversion over SAPO-34 and ZSM-5 catalysts was studied using thermodynamic equilibrium and Anderson-Schulz-Flory (ASF) distributions. The equilibrium compositions were calculated using constrained Gibbs free energy minimization. The effect of catalyst type was considered by setting upper limits to product carbon number due to shape selectivity according to zeotype catalyst channel size; that is, n£5 for SAPO-34 but n£6 for aliphatic and n£10 for aromatic compounds over H-ZSM-5 catalyst. The equilibrium selectivity of kinds of paraffin is negligible over SAPO-34 system while that of olefins is very small over H-ZSM-5, both in agreement with experimental results for methanol to olefins and to gasoline, respectively. The methanol to olefins hydrocarbon product distributions over SAPO-34 and H-ZSM-5 showed fair agreements with thermodynamic equilibrium and ASF distributions, respectively. It was found that propylene is the only product the selectivity of which can be maximized among hydrocarbon products over both SAPO-34 and ZSM-5 catalysts, and therefore, it can be an easier target molecule in methanol to hydrocarbon conversions.
    Keywords: Methanol to hydrocarbons, SAPO-34, ZSM-5, Shape selectivity, Equilibrium composition, Anderson-Schulz-Flory distribution
  • Boingotlo Setlhabi *, Abimbola Popoola, Lerato Tshabalala, Abraham Adeleke Pages 61-71
    This research was aimed at evaluating the efficiency of advanced gravity and magnetic separations on the recovery of chromite from the fine Platinum Group Metals (PGM) tailings consisting of particles 80% passing 75 µm with about 45% being >45 µm resulting in high chromite losses. The PGM plant tailings were subjected to X-ray fluorescence, scanning electron microscopy and particle size distribution analyses. The feed was then optimally classified with 60 mm diameter hydro-cyclone into underflow and overflow streams. The coarser underflow was further beneficiated using the spiral concentrator. The results obtained showed that the removal of fines increased the Cr2O3 grade for the spiral feed from 12.27% to 17.64% while spiral concentrate grade improved from 14.84% to 21.46% and recovery 69.85% to 95.53%. Magnetic separation efficiency was found to increase with particle size such that at >75 µm a concentrate with up to 17.13% grade and 61.5% recovery was achieved. The advanced Falcon concentration was also observed to be mainly particle size dependent and at 45 µm up to 17% grade and 60.3% recovery was achieved. The results obtained are based on particles >45 µm and the finer particles
    Keywords: Tailings, analyses, classified, beneficiated, Efficiency
  • Amir Hamdamali, Nader Shokoufi * Pages 73-83
    Dispersive Liquid-Liquid Microextraction / Thermal Lens Microscopy (DLLME/TLM) was developed as a new combination method for preconcentration and determination of Cd. Thermal Lens Microscopy is suitable for the determination of analyte after DLLME because of the low volume of the remained phase after DLLME and increasing of the enhancement factor for the nonpolar organic solvents. Some effective parameters on the micro extraction, complex formation and combination were selected and optimized. Under optimum conditions, the calibration graphs were linear in the range of 0.05-20 µg/L with the detection limit of 0.008 µg/L. The Relative Standard Deviation (RSD) for 1 and 10 µg/L of cadmium was 3.1 and 2.3, respectively. The enhancement factor of 1200 was obtained from a sample volume of 10.0 mL. DLLME/TLM method was applied to the analysis of real samples. The accuracy of the method was proved by using standard reference materials and micro spectrophotometry.
    Keywords: Thermal lens Microscopy, Dispersive, Real samples, Laser, Cadmium
  • Bejaoui Yosra, Abderrabba Manef, Ayadi Sameh * Pages 85-89
    Ruta species are known as a potential source of natural products with biological activities. They are used in several fields such as in therapeutic and traditional medicine. In order to contribute to the valorization of these plants, this work investigated the chemical composition and antibacterial activity of the essential oils of Ruta montana and Ruta gravelons growing in tunisia (north of tunisia). The total phenolic content of these two essential oils was also studied. The antibacterial activities of essential oils were assessed against Escherichia coli (ATCC7625), Staphylococcus aureus (ATCC76110), Pseudomonas aeruginosa (ATCC 7624), Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa. Results show that the chemical composition of essential oils was dominated by 2-undecanone (86.77%), followed by 2-decanone (4.91%) and 2-nonanone (23.62%). Furthermore, the total phenolic content in essential oil of Ruta gravelons is more important than the total phenolic content in essential oil of Ruta montana. Indeed, the value of total phenolic content is 41.70 mg Gallic acid equivalents per gram of dry extract, in essential oil of Ruta gravelons but the total phenolic content in essential oil of Ruta montana is a 7.50 mg  Gallic acid equivalents per gram of dry extract. Besides, the ruta montana essential oil has the most important antibacterial activity than the Ruta gravelons essential oil especially against Staphylococcus aureus (ATCC76110) and Pseudomonas aeruginosa (ATCC 7624).
    Keywords: Ruta montana, Ruta gravelons, essential oil, Antibacterial
  • ALI H. Jawad *, Dhafir T.A. Al, Heetim, Ramlah Abd Rashid Pages 91-105
    In this work, orange (Citrus sinensis) peels biochar (OPBC) were prepared by one-step H2SO4 activation for Methylene Blue (MB) adsorption from aqueous solution. The physicochemical properties of OPBC were characterized using instrumental analyses such as CHNS-O analyzer, Fourier Transform InfraRed (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and point-of-zero charge (pHpzc) analysis. Batch mode adsorption study was conducted by varying operational parameters such as adsorbent dosage (0.02 – 0.20 g), solution pH (3 – 11), initial MB concentrations (50 – 300 mg/L), and contact time (0 – 1440 min). The equilibrium data was found to better fit with Langmuir isotherm model compare to Freundlich and Temkin models. The maximum adsorption capacity, qmax of OPBC for MB adsorption was 208.3 mg/g at 303 K. The kinetic study revealed that the present system obeyed Pseudo-Second-Order (PSO), model. The thermodynamic adsorption parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°), and standard free energy (ΔG°) showed that the adsorption of MB onto OPBC surface endothermic in nature and spontaneous under the experimental conditions. All above-mentioned results indicate that the OPBC can feasibly employ for the elimination of MB from aqueous solution
    Keywords: biochar, Orange peel, Chemical activation, Adsorption, Methylene blue
  • Samaneh Shahsavani, Mansooreh Dehghani *, Narges Shamsedini Pages 107-112
    Direct Red 81, a dye widely used in textile industries, is frequently detected dye in water resources. High costs, the formation of hazardous byproducts, and high energy costs restrict the use of some removal methods. Therefore, the main objectives of this research are the feasibility of using soil containing iron as a low cost adsorbent to remove (Direct Red 81) from aqueous phase and determining the optimum conditions for maximum removal efficiency. The present study was conducted at a bench scale. The influence of different parameters including the number of adsorbents; initial concentration of dye solution and pH at different time intervals on dye removal efficiency were investigated.  The maximum removal rate of dye (84%) occurred in pH=7 in the presence of 1 g soil with the initial dye concentration of 50 mg/L at 30 min reaction time. Moreover, due to the effect of acidic pH and the iron content of used soil a significant increase was observed in the rate of Direct Red 81dye removal. In conclusion, using soil containing iron is an appropriate method for the removal of Direct Red 81 from aqueous solutions.
    Keywords: Adsorption, Dye removal, Direct Red 81, aqueous solution, Soil containing iron
  • Aref Shokri * Pages 113-119
    IIn this study, the Electro Coagulation (EC) was used for the removal of acid orange 5 from synthetic wastewater in a batch electrochemical reactor. The impact of the operational variables such as current density, initial pH, time of electrolysis, and initial concentration of the dye was investigated. The results showed that the optimum conditions were obtained at initial pH of 7, current density at 2 mA/cm2, 60 mg/lit of Acid orange 5 and time of reaction at 60 min. At optimum conditions, the removal efficiency of acid orange 5 and Chemical Oxygen Demand (COD) were 99.3 and 85.5%, respectively. The kinetic study showed that the removal reaction was first order and the rate constant and half-life of reaction were obtained.
    Keywords: Electro coagulation (EC), Acid orange 5, Electrochemical reactor, current density, Chemical oxygen demand (COD)
  • Nurten Deva *, Musa Rizaj, Ismail Duman, Florian Kongoli Pages 121-126
    The aim of this research is to get a better understanding of the electrolytic refining process in order to yield the anode slime. Three types of secondary copper anodes are electro refined in an electrolytic system, where the electrolyte is an acid of copper sulphate solution. As a result of the electro-refining process the anode slime has been gained as secondary product. The experimental research analysis of anode slime composition is done by two
    methods
    X-Ray Fluorescent (XRF) method which is realized with the help of Thermoscientic Nitro XL 3t device and as second method X-Rays Diffractometry (XRD) is used, which is realized with the help of D8 Advance Bruker AXS equipment. The anode slime introduces a multi-component secondary product of electrolytic refining process of metals composed of insoluble components of Cu, Au, Ag, Pt, Pd, Ir, etc. The composition of the anode slimes varies according to the composition of the anodes. The qualitative preparation of raw material – anode slime of secondary Cu and its rational utilization will result in the optimization of the process of gaining metals for which it is dedicated. This study has shown that the anode slime contains gold, silver and platinum group of metals and these metals can be recovered.
    Keywords: Anode slime, copper, Gold, Silver, PGM, Electrorefining
  • Veselinka Grudic, Ivana Boskovic *, Dragan Radonjic, Zeljko Jacimovic, Bojana Knezevic Pages 127-138
    This paper studies the corrosion inhibition of Al-Mg alloy system in 0.5 mol/dm3 NaCl solution in the presence of pyrazole derivative using potentiodynamic polarization and linear polarization method. The inhibition efficiency as a function of concentration and temperature was investigated. From the polarization curves, it can be concluded that the pyrazole derivative behaves like a mixed inhibitor. It has been shown that the efficiency of the inhibitor increases with increasing concentration and with increasing temperature and it indicates a chemisorption process. It was concluded that the pyrazole derivative adsorbed on the electrode blocks the active surface sites and reduces the corrosion rate. The kinetic and thermodynamic parameters of the adsorption process were determined. The relatively low efficiency of the inhibitor at room temperature could be an indicator of increased desorption in the adsorption-desorption equilibrium process. With increasing temperature the equilibrium is shifted in the direction of adsorption, causing an increasing inefficiency. Also, the positive values of equilibrium adsorption constant Kads indicate chemisorption of the pyrazole derivative on the alloy surface. The values of the activation energy in the presence of inhibitor were lower than in the uninhibited solution, which also indicates the chemical adsorption. Negative values of adsorption free energy ΔGads show that the adsorption process is spontaneous.
    Keywords: corrosion rate, pyrazole derivative, inhibition efficiency, Adsorption isotherms
  • Chun Hui Ang, Sook Mei Khor *, Khairun Fadila, Cheng Hock Pages 139-152

    The chemical constituents of leaves, inflorescence, and flowers from Ocimum basilicum (Thai basil) and Ocimum sanctum (Holy basil) were analysed by gas chromatography-mass spectrometry. The chemical compounds were extracted by hydrodistillation, headspace-solid phase microextraction, and solvent extraction.  The main constituents of Ocimum basilicum were identified to consist of estragole (> 35.71%), (E)-β-ocimene (> 1.47%), trans-α-bergamotene (> 0.83%), τ-cadinol (> 0.41%) eucalyptol (> 0.25%) and α-caryophyllene (> 0.07%) while Ocimum sanctum consists mainly of eugenol methyl ether (> 34.34%), (E)-caryophyllene (> 7.91%), germacrene D (> 5.58%), β-elemene (> 4.22%) and copaene (> 1.49%).  Ocimum basilicum and Ocimum sanctum leaves contain more chemical constituents followed by inflorescence and flowers. The genetic distance between the two species was calculated to investigate the interspecies relationship and it is 2.86. The calculated genetic distance between the two species showed that Ocimum basilicum and Ocimum sanctum are closely related species and share some of the same traits.  The methanol and dichloromethane extracts of Ocimum basilicum leaves showed an IC50 value of 88 μg/mL and 1178 μg/mL, respectively, while the methanol and dichloromethane extract of Ocimum sanctum showed a higher 2, 2-diphenyl-1-picrylhydrazil free radicals scavenging activities with an IC50 value of 11 μg/mL and 369 μg/mL, respectively. The natural antioxidant level Ocimum sanctum and Ocimum basilicum indicated that they can be used effectively in food preservation.

    Keywords: Ocimum basilicum, Ocimum sanctum, Free radical scavenging activity, Chemical constituents, Genetic distance
  • Rahim Ada, Ercan Ceyhan, Şadiye Ayşe Çelik, Mustafa Harmankaya, Mehmet Musa Özcan * Pages 153-158
    Metal, non-metal and and heavy metal contents of different pea genotype seeds were determined by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). For all genotypes, significant differences were observed in the mineral contents. Potassium was the most abundant element, ranged from 10146.13 mg/kg (PS3048) to 13171.97 mg/kg (PS3053) (Table 1). In addition, the phosphor content of pea seeds was found between 4004.31 mg/kg (PS 30100) and 5651.27 mg/kg (PS 3057). These pea genotypes contained 1562.32 mg/kg to 2034.28 mg/kg magnesium. Zinc contetns of pea samples changed between 29.66 mg/kg (PS 3055) and 67.81 mg/kg (PS 4053 B). The oil contents of pea samples ranged from 0.84% (PS4053 B) to 3.59% (PS 3055). Oleic acid is predominant fatty acid 12.95% to 45.02% followed by palmitic 13.68% to 77.28%, stearic (1.66% to 15.99%) acids. The highest oleic acid was found in PS3048 genotype (45.02%). The highest palmitic acid was found in PS4021 pea sample (77.28%). The current study contributes to the available information concerning the composition of several pea genotypes grown in Turkey. Fatty Acid Composition and Mineral Contents of Pea Genotype Seeds
    Keywords: pea, genotypes, oil, Protein, mineral, fatty acid composition, GC, ICP-AES
  • Alaleh Zoghi, Kianoush Khosravi, Sara Sohrabvandi, Hosein Attar, Sayed Abolhasan Alavi* Pages 159-170

    The aim of this work was to produce synbiotic apple juice and investigate the survival of Lactobacillus acidophilus and Lactobacillus plantarum in apple juice during the refrigerated storage (4 °C) for 42 days and then the ability of the mentioned probiotic bacteria in gastrointestinal tolerance under gastrointestinal tract conditions, with simulated gastric and bile juices. Eight-treatment combination Plackett-Burman design was used to evaluate the influence of seven variables such as probiotic strain, inoculum size, fructooligosaccharide content, inulin concentration, patulin content, ascorbic and citric acids concentration on the viability of mentioned probiotic strains. The results showed that the survivability of probiotics in apple juice depends significantly (P ≤ 0.05) on the inoculum size, inulin concentration, kind of probiotic strain, and ascorbic and citric acids’ concentration, respectively. The highest viability was achieved by inoculation of 108 CFU/mL of Lactobacillus acidophilus ATCC 4356 to the apple juice contaminated with 110 µg/L patulin content, containing 2.5% (w/v) inulin, 4 g/L citric acid, and 200 mg/L ascorbic acid. No significant difference was observed in the organoleptic properties of the synbiotic apple juice and the control sample. After sequential incubation in the simulated gastric (2 h) and intestinal juices (pH 7.4, 2 h), the highest number of surviving cells was around 3.5 log (CFU/mL).

    Keywords: Viability, Probiotic, Functional food, Prebiotic, Simulated gastro-intestinal juices
  • Faleeha Hasan Hussein, Sayed Hadi Razavi *, Zahra Emam Djomeh Pages 171-181
    Probiotic fermented sausages are safe and healthy meat products. Semi-dry fermented sausages were manufactured from camel meat inoculated with Lactobacillus casei and Lactobacillus paracasei and control. All treatments were analyzed for the  physico-chemical characteristics (Protein, Moisture, Fat, Ash, Lactic acid value and pH), microbiological features (total aerobic, total mold and yeast and lactic acid bacteria count)  and sensory evaluation (color, flavor, texture and overall acceptability) after 0, 10, 20, 30, 40 and 45 days of refrigerated storage at 4°C. The microbial analysis demonstrated the predominance of lactic acid bacteria in semi-dry fermented sausage during the cold storage which reached (8.07) log CFU/g in samples inoculated with Lactobacillus paracasei at 4°C for 45 days. Chemical analysis of semi-dry fermented sausage showed a significant difference (p<0.05) in moisture content which decreases in all samples during the period of cold storage. However, all other parameters such as protein, fat, and ash increased. The dropped in pH value in all samples because of producing lactic acid during the fermentation by lactic acid bacteria. Physicochemical, microbial and sensory characteristics of fermented sausage inoculated with Lactobacillus paracaseiare found to be better than other ones. Also, we could preserve the product at 4°C for 45 days. The sensory evaluation has appeared superiority in the semi-dry fermented sausage that had Lactobacillus casei and Lactobacillus paracasei compared with control.
    Keywords: Lactic acid bacteria, Production semi-dry fermented sausage, Quality characteristics
  • Kianoush Khosravi*, Solmaz Zarean, Negin Ahmadi, Zahra Hadian, Amir Mohammad Mortazavian Pages 183-192

    Production of fermented functional foods containing micronutrients is required for their health beneficial properties. The impact of 11 process variables on vitamin B12 production in a dairy beverage containing propionic acid was investigated. Propionibacterium freudenreichii ssp. shermanii was applied in a 3-l fermentor in the fed-batch fermentation system. The most suitable conditions for vitamin B12 production were achieved by 5% v/v inoculum size containing Propionibacterium freudenreichii (without Lactobacillus acidophilus) and continuous feeding of lactose with the rate of 0.04 l/h at 36°C in a medium containing 25 g/L molasses, 10 g/L corn steep liquor, at pH=6.5, after 96 h fermentation. Maximum vitamin concentration (30 mg/L) and productivity (7.5 mg/L.day) were obtained in trial 9. Organoleptic properties of the fermented beverage were also acceptable for panelists and no significant difference was observed between samples and control during 6 days refrigerated storage.

    Keywords: Co-culture, Fed-batch fermentation, Plackett-Burman, Process variables, Propionibacterium freudenreichii, Propionic acid, Vitamin B12
  • Leila Amirkhani, Jafarsadegh Moghaddas *, Hoda Jafarizadeh Pages 193-201
    Hydrophobic magnetic silica aerogel was used as a support to immobilize Candida rugosa lipase by adsorption method. Physical and chemical properties of the support and immobilized lipase were determined by Field Emission Scanning Electron Microscope (FESEM), Brunauer–Emmett–Teller (BET) analysis and Fourier Transform InfraRed (FT-IR) spectroscopy and the results showed that the lipase was successfully immobilized onto the support. Biodiesel production from sunflower oil using immobilized lipase was investigated. Response Surface Methodology (RSM) was employed to evaluate the effect of process variables namely methanol/oil molar ratio (4:1-6:1), enzyme concentration (4-10 % mass fraction of oil) and water concentration (3-10 % mass fraction of oil) on biodiesel yield and predict the optimal reaction conditions. A second-order regression model with a high coefficient determination value (R2= 0.99) was fitted to predict the response as a function of reaction parameters. The results indicated that optimum values for methanol/oil molar ratio, enzyme concentration, and water concentration were obtained at 4.5:1, 9.4% and 7.4 %, respectively, in which biodiesel yield was predicted at 72.3%. As the difference between the experimental and predicted values were shown as non-significant, the response surface model employed could be considered as adequate.
    Keywords: Biodiesel, Magnetic silica aerogel, Candida Rugosa Lipase, Transesterification, Response surface methodology (RSM), Optimization
  • Hamid Mosmeri, Ali Bahrami *, Mohammad Ghafari, Khaled Jazaieri Pages 203-214
    In the present study, the solvent-solvent extraction of phenazine 1-carboxylic acid (PCA) as an environmentally friendly antifouling agent from pseudomonas aeruginosa MUT3 culture was investigated. Accordingly, after screening the extraction ability of various solvents, the combined effects of operating parameters such as solvent type (ethyl acetate, dichloromethane, and n-hexane), solvent percent and mixing time on the PCA extraction process were analyzed using response surface methodology (RSM). As a consequence, ethyl acetate showed higher extraction yield (68%) and the optimum condition for PCA extraction were identified as 150% of solvent and 120 min mixing time. Meanwhile, the extraction yields for dichloromethane and n-hexane were measured by HPLC assay around 48.75 and 25.2%, respectively. The accuracy of the obtained model was proved by 99.90% R2 and 99.84% Adj R2. In addition, the disk diffusion test showed 9.2, 8 and 7.3 mm inhibition zone for ethyl acetate, dichloromethane and n-hexane, respectively. Consequently, the present study provided a great insight into the solvent-solvent extraction of antibiotics from the fermentation broth.
    Keywords: Phenazine 1- carboxylic acid, Response surface methodology, Solvent extraction, cross current, production yield
  • Koteswara Reddy G, Kiran Yarrakula * Pages 215-228
    The purpose of the study was to investigate the mineralogical and Heavy Metals (HMs) present in the granite mining soils in Chimakurthy, India. The mineral exploration of mining soils were identified by X-Ray Diffractometer (XRD) pattern analysis. However, the morphological features and quantitative HMs were detected by Scanning Electron Microscopy/Energy Dispersed Spectroscopy (SEM/EDS). The relative concentrations of HMs measured by Atomic Absorption Spectrometry (AAS). In this study, the major minerals were identified as Quartz, Albite, Anorthite, K-Feldspars, Hornblende, Muscovite, Annite, Lepidolite, Illite, Clintonite, Enstatite, Ferrosilite, Kaolinite, Kyanite, Augite, and Phologopite. Moreover, the presence of six HMs such as Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn) and Manganese (Mn), and their relative concentrations were measured.  The concentrations of HMs in three groups of mining soils were in the range of Cr: 149-177 mg/kg (>100), for Co: 128-175 mg/kg (>50), for Ni: 166-204 mg/kg (>50), for Cu: 288-363 mg/kg (>100), for Zn: 433-548 mg/kg (>200) and for Mn: 714-769 mg/kg (<2000) as compared with maximum permissible levels set by standard organizations (WHO/FAO) limits. The results demonstrated that the HMs concentrations in mining soils were exceeded WHO/FAO limits except for Mn. The study is useful for assessment of environmental impact due to excessive deposition of mineral waste and assessment of the quality of investigated granites based on their mineralogical aspect, particularly in the production of granite stones.
    Keywords: Granite, Minerals, heavy metals, XRD, SEM, AAS
  • Somayeh Shayanfar, Valeh Aghazadeh *, Abdoullah Samiee Beyragh Pages 229-238
    Bayerite is one of the phases of aluminum hydroxide which is precipitated by the carbonation of aluminate solutions obtained from sintered nepheline syenite leaching. In this study, the conditions for the bayerite formation were predicted by thermodynamic modeling of the carbonation process and the Bromley- Zemaitis model was used for this purpose. Carbonation experiments were carried out at pH 11 and the temperature range of 50- 90 °C based on the data obtained from thermodynamic modeling results. XRD analysis of products showed that bayerite was the predominant phase at all temperatures. SEM and LDS analysis indicated that the bayerite precipitates had uniform morphology and bimodal particle size distribution with mean particle size of 4.6 μm at 50 °C to 12.9 μm at 90 °C. It was found that the d50 increased slowly at the precipitation temperature ranging from 80 to 90 °C, from 12.6 to 12.9 μm and the effect of temperature was on the shape of particles. XRF analysis of the products indicated that the amount of Al2O3 and SiO2 in the bayerites decrease by increasing the temperature. According to the thermodynamic modeling data and experimental results, the temperature of 80 °C and pH 11 were determined as optimal conditions for bayerite precipitation.
    Keywords: Aluminate solution, Carbonation, Bromley-Zemaitis model, Bayerite
  • Jiang Fan *, Sijie Li, Qingfeng Wu, Zhenzhang Liu Pages 239-252
    The study on the flow behave inside of a ball valve is important for heavy crude oil transportation. Owe to the fast progress of the numerical technique, it becomes an effective way to observe the flows inside a valve and to analyze the flow structure of the oil-water core annular flow. In the present study, the simulation of the oil-water core annular flowing through the valve is conducted by combined the VOF and CSF model, and the effects of open rate on vortex and oil distribution characteristics are analyzed. The simulated data is a satisfactory match with empirical value and the experimental results. The results show that there are lots of vortexes inside and behind the valve, the coordinate values of the vortex decrease and the aggregation rate increases with an increase in open rate. As the input velocity increases, the change rate of the vortex position is greater, and the oil aggregation rate decreases, the highly viscous oil with has greater aggregation rate after flow through the valve, and the variation of the vortex core position is relatively slow. As the vortex flow across the oil core, the oil will be scattered and contributes to the instability of the annular flow.
    Keywords: the ball valve, oil-water annular flow, VOF, vortex, oil phase distribution, numerical simulation
  • Nadia Khan, Hamza Bin Rafiq, Asra Nafees, Haslinda Zabiri, Syed Ali Ammar Taqvi * Pages 253-261

    Coal-Water Slurry (CWS) is an attractive alternative fuel with lower cost and reliable in terms of transportation and handling. The efficiency of CWS gasification depends on the preparation of CWS to ensure the higher carbon contents and low viscosity which will enhance the heating rates along with the atomization of CWS. In this paper, the rheology of CWS was studiedwith coal loading 30 to 60% and the rheological behavior was discussed with the help of Power-law, Casson and Herschel Buckley models which shows that CWS exhibits pseudo-plastic (shear thinning) behavior. The CWS was prepared by using Poly-Vinyl Alcohol (PVA) and Triethanol Amine (TEA) as dispersants and Xanthan gum as a stabilizer. The experimental results showed that for a constant coal loading viscosity decreases as the shear rate increases and out of these rheological models, power-law fits best on the experimental data with the highest R2 of 0.99

    Keywords: Coal preparation, Coal water slurry, rheology, coal gasification