فهرست مطالب

Iranian Journal of Chemistry and Chemical Engineering - Volume:40 Issue: 4, Jul-Aug 2021
  • Volume:40 Issue: 4, Jul-Aug 2021
  • تاریخ انتشار: 1400/07/21
  • تعداد عناوین: 29
|
  • Esmail Vessally*, Parya Farajzadeh, Ezzatollah Najafi Pages 1001-1011

    In this research, we studied the most stable configurations, electronic properties, and interactions between pristine and Al- and Si-doped boron nitride nanosheet BNNS and the methimazole drug MM by using Density Functional Theory (DFT) calculations. The results indicate that MM can be physically interacting into the pristine while chemically interacts with Al- and Si-doped BNNS. With the weak interaction and low change in Eg between BNNS and MM, this system seems is not suitable for potential sensing while Si-doped BNNS indicates a suitable interaction and high change in Eg during absorption of MM; showing a good candidate for a sensing device. The Al-doped BNNS shows a strong interaction with MM that leads to a high recovery time; indicating this system is suitable for decomposition of MM.

    Keywords: Al-, Si-doped boron nitride BNNS, Nanosheet, Methimazole drug, Adsorption, Sensing ability, DFT, Drug delivery system
  • Najm Us Saqib, Rohana Adnan, Irfan Shah Pages 1012-1022

    Visible light-driven Ag+ doped TiO2 photocatalysts were successfully prepared with modified low-cost Liquid Impregnation (LI) method yielding up to 95 % product. The native and newly synthesized photocatalysts were calcined at various temperatures and characterized using diffused reflectance spectroscopy (UV/Vis-DRS), XRD, XPS, TEM, EDX, XRF, and pHPZC analyses. The XRD results for all samples revealed that the anatase phase was dominant at all calcination temperatures. The Ag+ doping reduced the bandgap energy to 2.88 eV, which significantly enhanced the photocatalytic efficiency towards Methylene Blue (MB) under compact fluorescent light. The photocatalytic efficacy of the nano-catalysts was also tested using a binary solution containing a model dye (MB) and Cd2+ under ordinary compact fluorescent light. The presence of competitive ions i.e. Cd2+ increased the MB degradation up to 4 folds under the ambient conditions whereby the maximum amount of MB adsorbed by nano-catalysts reached 46 mg/g. The high-temperature combustion method was found more effective for the regeneration of TiO2 photocatalysts compared to the chemical regeneration. The reusable character of the regenerated samples posed a significant impact on the current work to be applied in wastewater treatment in bulk.

    Keywords: Titanium dioxide, Doping, Degradation, Photocatalysis, Regeneration
  • Vusala Asim Majidzade, Akif Shikhan Aliyev Pages 1023-1029

    The present contribution is devoted to the production of the Ni-Bi-Se thin films widely used in the field of electronics, electrotechnology, and computer technology. During the process, at first, the Bi-Se compound has been formed on the nickel electrode by electrochemical method, and then by thermal treatment of this compound at 673K, ternary compound Ni3Bi2Se2 has been obtained. The results show that as the concentration of bismuth is increasing, its amount in deposited films increases regularly. The formation of the Ni3Bi2Se2 compound was also confirmed by XRD results. The photochemical properties of the obtained compounds were investigated in the dark and light, constant current of 100 nA for 0-600 seconds. With the illumination of the dark samples, the potential shifts from a positive side to a negative side, this decrease indicates that obtained thin films are not only photosensitive, also have n-type conductivity.

    Keywords: Ni3Bi2Se2, Electrodeposition, Chemical compounds, Thermoelectric materials
  • Zeinab Azin, Zeinab Pourghobadi Pages 1030-1041

    This study aimed at preparing a Carbon Ionic Liquid Electrode (CILE) modified with a new composite of Multi-Walled Carbon Nano-Tubes (MWCNTs) and TiO2 nanoparticles for AC determination. The proposed electrode was made of a Carbon Paste Electrode (CPE) modified with TiO2 Nano-Particle (NP)-decorated MWCNTs and a binder of IL 1-hexyl-pyridinium hexafluorophosphate (HPFP) (MWCNT/TiO2/CILE). The nanocomposite structure characterization was done via X-ray Energy-Dispersive Spectroscopy (EDS) and Field-Emission Scanning Electron Microscopy (FESEM). The electrochemical behavior of Ac was investigated via the Cyclic Voltammetry (CV) technique at the MWCNT/TiO2/CILE. The MWCNT/TiO2/CILE was applied for Ac determination by Square-Wave Voltammetry (SWV) technique in real samples. The excellent electrocatalytic activity of the proposed nanocomposite leading to Ac electrochemical oxidation in phosphate buffer solution (pH 6.0) was evidenced. The results of Square-Wave Voltammetry (SWV) revealed a wide linear range of 0.01-30 µM and the detection limits of 0.003 µM for the modified electrode under optimal conditions. This electrode was successfully employed to detect Ac concentrations in plasma and tablet samples with good repeatability and reproducibility

    Keywords: Acetaminophen, TiO2 nanoparticles, Electrochemical, Carbon Ionic LiquidElectrode (CILE), Determination
  • Zahra Aramesh Boroujeni, Zahra Asadi Aghbalaghi Pages 1042-1053

    he electro-oxidation of venlafaxine (VEN) was investigated at a carbon paste electrode, the modified electrode by NiO/Graphene Reduce (GR) nanocomposite. The structure and morphological aspects of the nanocomposite were approved using FE-SEM, EDAX, and FT-IR. The electrode reaction process was a diffusion-controlled one and the electrochemical oxidation involved two electrons transferring and two protons participating. Under the optimized conditions, the electro-oxidation peak currents were linearly dependent on the concentration of VEN in the concentration range from 1.0- 40.0 μM with the limit of detection (S/N=3) as 0.05 μM. The proposed method has been successfully applied in the electrochemical quantitative determination of VEN content in real samples and the determination, results could meet the requirement of the quantitative determination.

    Keywords: Venlafaxine, Electro-oxidation, NiO, GR nanocomposite, Modified carbon pasteelectrode
  • Jalel Ben Nasr, Achraf Ghorbal Pages 1054-1066

    Dyes represent a serious threat to the environment when released in wastewaters. Hence, the main objective of this work was to design and fabricate an activated carbon from an invasive plant – Agave Americana L – capable of removing indigo carmine in aqueous solutions. The equilibrium adsorption of indigo carmine was assessed using the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm model. The zinc chloride was used to activate the powder of Agave at 600 °C and 900 °C. The results of this work showed that the elaborated activated carbon had maximum adsorption of 61.72 mg/g and a specific surface area of 38 m²/g determined using the BET method. The thermodynamic study showed that the adsorption of indigo carmine on the activated carbon was endothermic. Therefore, the activated carbon prepared from the Agave Americana L would be an efficient and cost-effective alternative adsorbent of indigo carmine and would have a positive effect on the environment.

    Keywords: Agave Americana L, Activated carbon, Adsorption, Indigo Carmine
  • Sangeetha Jayaraman, Venugopal Thiruvenkadam Pages 1067-1082

    The sorption ability of readily available barks of Prosopis cineraria (PCAC) activated by orthophosphoric acid was investigated through the effect of various process parameters such as initial dye concentration [(50 to 200) mg/L], contact time, solution pH (3 to 10), and temperature [(298K to 328K] and optimized using Response Surface Methodology (RSM). The physiochemical activation process was used to yield a sample with a Brunauer-Emmett-Teller (BET) surface area of 7.024 m²/g. The Activated carbon was characterized by using FT-IR and SEM. The various adsorption isotherms and kinetic models were used to interpret the experimental data. Good agreement was found between the experimental results and predicted values by RSM and about 88%, 70%, and 93% of removal efficiencies were achieved for cationic (Methylene Blue (MB), Rhodamine B (RHB), and Rhodamine 6G (RH6G) dyes with concentration 70 mg/L.

    Keywords: Sor1067ption, Activated, Isotherm, Kinetic, Response Surface Methodology, Cationic dyes
  • Reza Moradi Pages 1083-1094

    In this paper, cobalt ferrite (CoFe2O4) nanoparticles were synthesized using the precipitation method. CoFe2O4 nanoparticles were used as a catalyst for photocatalytic degradation of azo dye in an aqueous solution. Acid Yellow 23 (AY23) was used as a model dye. The CoFe2O4 catalyst was characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). A batch photoreactor with a capacity of 1L, equipped with a lamp UV-C (15 W) was used. A statistical experimental design based on Yates’ Algorithm was exerted to measure the effect of these four factors such as pH, catalyst amount, H2O2 concentration, and temperature at two levels. The (24 ) full factorial experimental design was utilized in this process. The significant effects of each factor and interaction on the process were determined using the Analysis of Variance (ANOVA) method. A pseudo-first-order reaction with a constant rate (k= 0.048 min−1 ) was obtained for the photocatalytic degradation reaction.

    Keywords: Cobalt ferrite, Full factorial, Degradation, Yates’ algorithm
  • Song Yinghua, Peng Rong, Gou Lili, Ye Mei Pages 1095-1104

    The present research was aimed to analyze the possibility of a novel low-cost biosorbent, Methanol Modified Walnut Shell (MMWS), to improve its biosorption properties with respect to the removal of Sunset Yellow (SY) from aqueous solution, The influences of process parameters, such as pH, temperature, and initial concentration of SY on its adsorption capacity were investigated in a batch system. The equilibrium data were evaluated using the Langmuir and the Freundlich models and the latter could provide a better fit. The Langmuir maximum adsorption capacity of SY onto MMWS was 18.35 mg/g at 298 K, which showed a significant improvement as compared to the raw walnut shell. The obtained thermodynamic parameters demonstrated a spontaneous and endothermic nature of the adsorption process of SY onto walnut shell biomass. The adsorption kinetics fitted well with the pseudo-second-order model. It was concluded that intra-particle diffusion was one of the rate-controlling steps in this process. MMWS was proved to be a promising adsorbent to treat dye wastewater.

    Keywords: Walnut shell, Adsorption, Sunset yellow, Modification, Mechanism
  • Rahim Boveiri Shami, Vahideh Shojaei, Hamid Khoshdast Pages 1105-1120

    A sample coal tailings activated by Sodium Dodecyl Sulfate (SDS) surfactant was used as an efficient adsorbent for the removal of lead from an aqueous solution. The effects of three factors, namely, initial solution pH (3-11), absorbent to lead ratio (12.5-162.5), and contact time (3-31 h), on lead removal, were studied and optimized using response surface methodology. Statistical analyses showed that all factors significantly affect lead removal. Process optimization resulted in maximum lead removal of 99.64% at initial solution pH of 6.75, absorbent to metal ratio of 91.33 and 20 h equilibrium contact time, and 97.4% removal after about 40 min. Kinetic studies revealed that lead adsorption follows the first-order model with a rate constant of 10.39 h-1 . The selectivity study in bimetal aqueous systems using copper, lead and zinc metals showed the adsorption order of Cu2+ > Pb2+, Pb2+ > Zn2+ , and Zn2+ > Cu2+ with some unusual trends. The lead adsorption on activated coal tailings was also found to follows the Freundlich isotherm model. The interaction mechanisms between SDS and the surface of coal tailings particles were also discussed. This study demonstrates that SDS-activated coal tailings could be considered as a promising efficient, low-cost, and easily available adsorbent for the treatment of heavy metal polluted wastewaters.

    Keywords: Coal tailings, Sodium dodecyl sulfate, Heavy metal, Adsorption, Kinetics, Selectivitystudy
  • Ramaraj Bhaviya Raj, Mahalingam Umadevi, Ramasamy Parimaladevi Pages 1121-1131

    Environmental problems caused by organic pollutants can be resolved by semiconductor photocatalysts. Using the strategies of doping hydrothermally, Zinc oxide/Bismuth oxide nanocomposites (ZnO/Bi2O3 NCs) comprising of different proportions of BiO for the applications of basic dyes and were tested for antibacterial activity. The average crystallite sizes of these, metal oxide nanocomposites were ranging from 12 nm to 29 nm. UV-Visible diffuse reflectance spectra were used to determine the optical energy bandgap (Eg) of about 2 to 2.82 eV of the NCs for different proportions of the metal oxides. Square-like morphology of ZnO NPs and ZnO/Bi2O3 NCs were observed in the Scanning Electron Microscopy (SEM). This morphological structure along with its high surface area attributes to the promotion of degrading organic pollutants in dyeing wastewater along with decolorization. The Photoluminescence (PL) emission intensity of ZnO/Bi2O3 NCs suggests a lower recombination rate of photogenerated charge carriers leading to enhanced photocatalytic activity. Visible light-driven photodegradation of MB, MG, and R6G by 0.5M ZnO: 0.5M Bi2O3 resulted in high rate constants of 8.5×10-3 /min, 6×10-3 /min, and 9×10-3 /min. The hybrid ZnO/Bi2O3 NC materials showed immense antibacterial activity against gram-positive bacterium S. aureus and the gram-negative bacterium E. coli with an inhibition zone of 6mm and 5mm respectively which was comparable to the standard, chloramphenicol. A desired predominant gram-positive bacterial inhibition unwraps a new way for enhanced antibacterial agents. The heterojunction at the interface between Bi2O3 and ZnO could efficiently reduce the recombination of photoinduced electron-hole pairs and thereby enhancing the photocatalytic and antibacterial activity of ZnO/Bi2O3 heterostructures. This study reveals that ZnO/Bi2O3 NCs as a promising candidate for the photocatalytic and antibacterial treatment of dye effluent.

    Keywords: ZnO, Bi2O3 nanocomposites, X-ray diffraction, energy bandgap, photoluminescence, photocatalytic activity, antibacterial activity
  • Hamid Hajmohammadi, Abdol Hamid Jafari, M. Eskandari Nasab Pages 1132-1147

    Adsorption of Sc from single and bi-component Sc-Y solutions by Purolite C100Na was studied experimentally and kinetic and thermodynamic characteristics are described. The extended Freundlich isotherm was found to be successful in validating the experimental results. Moreover, the curve fitting the time-dependent data into different kinetics mechanisms showed a satisfactory correlation with the pseudo-second-order model. Binary system resultsshow a decrease in Sc adsorption capacity of the absorbent in presence of secondary ions due to competition for adsorption sites. Furthermore, thermodynamic parameters indicate similarity of reaction mechanisms for both single and binary systems, with Sc absorption adversely affected by temperature. Results from synthetic solutions with an actual Y/Sc ratio of 5 were used for extracting scandium from actual mining copper leach solution by circulating it through a resin column. The results demonstrate a satisfactory collection of Sc ions despite the fivefold concentration of Y over Sc. The elusion studies showed that the yttrium desorption peak occurs before that of Sc which corroborates the adsorption isotherm findings. This results in a 180 mg/L Sc rich solution or 60:1 concentration ratio over the original copper leach solution.

    Keywords: Scandium, Yttrium, Adsorption, Ion exchange, Thermodynamic isotherm, PuroliteC100
  • Alireza Noorpoor, Maryam Avishan, Saeed Nazari Kudahi Pages 1148-1161

    In the present work, experimental and theoretical aspects of CO2 adsorption on the amine-modified pumice, as a new adsorbent, was investigated. CO2 adsorption measurements were performed at three different temperatures (298, 328, and 348 K), and pressures up to 1 atm. To determine the best-fitting isotherm, the experimental equilibrium data were analyzed using eight adsorption isotherm models with two and three parameters. Four two-parameter equations, namely the Langmuir, Freundlich, BET, and Temkin, and four three-parameter equations, namely the Redlich-Peterson, Sips, Toth, and Dubinin- Astakhov were used. To evaluate the adequacy of the fitting of the isotherm models, the average relative error was calculated. Furthermore, Henry's law constant for evaluating the adsorption affinity of CO2 on the adsorbent was estimated by the Virial model. The results showed the modified pumice demonstrated better adsorption at the temperature of 298 K. Its adsorption capacity (0.510 mmol/g) was almost twice as much as that of raw pumice. The Freundlich model, in comparison with the other two-parameter models, and the Sips model, compared to the other three-parameter models, showed the best correspondence with CO2 adsorption’s experimental data, with average relative errors of less than 3% observed at all temperatures. The results suggest that the amount of E (kJ/mol) (the characteristic energy of adsorption D-A isotherm) at 298K and 328K was lower than 8, which indicates the domination of the physical adsorption mechanism in the process of CO2 adsorption on modified pumice.

    Keywords: CO2 adsorption, Pumice, Adsorption isotherm models, Henry's law constant
  • Shima Kazemi, Ahad Ghaemi, Kambiz Tahvildari Pages 1162-1178

    The important environmental concern of the carbon dioxide (CO2) capture by the absorption process with amine solutions is studied in the current study. The experiments are performed at operating conditions of a temperature range of 25 ̶65 C, a pressure range of 1.5 ̶6.5 bar, diethanolamine (DEA) concentration of 0 ̶1.5 M, PZ concentration of 0 ̶0.5 M, and stirrer speed of 0 ̶300 rpm. The effects of operating conditions on CO2 loading, absorption rate, and mass transfer flux are investigated into two solutions of DEA and DEA+piperazine (Pz) blend in a stirred reactor. In the DEA+CO2+H2O system, by increasing stirrer speed from 0 to 300 rpm, the maximum values of CO2 loading and mass transfer flux at the same DEA concentration are increased 65% and 137%, respectively. The CO2 loading and mass transfer flux have higher values at higher initial pressures. The predicted values for species concentrations into the DEA+CO2+H2O system are also evaluated based on the Pitzer model, mass, and charge balance equations. The results showed that by increasing stirrer speed, the concentration of DEA molecule is decreased 40% but the concentrations of other ions and molecules are increased. In the DEA+Pz+CO2+H2O system, the results indicated that adding Pz to the absorbent solution was more efficient in CO2 capture relative to only the DEA solution. The equilibrium CO2 loading is increased by 20% and 16% for blend solutions with 4:6 and 6:4 molar ratios of DEA and Pz, respectively, but using only Pz solution is increased it up to 29%.

    Keywords: CO2 absorption, DEA, Pz, Blended amine, Mass transfer flux, Thermodynamic
  • Hossein Kazemi, Shahrokh Shahhosseini, Mohsen Amiri Pages 1179-1194

    Sodium carbonate (Na2CO3) supported by gamma-alumina (-Al2O3) is one of the best sorbents for CO2 capture in economic terms because of its low raw material cost and excellent performance in low-temperature operation. The fundamental goal of this study is to optimize the operating conditions of CO2 adsorption by Na2CO3/Al2O3 sorbent in a fixed bed reactor. The sorbent characterization was studied using BET, SEM, XRF, and XRD analyses, and the sorbent structure was compared before and after the carbonation reaction. Moreover, the effects of side reactions on the adsorption process were investigated. The Response Surface Methodology (RSM) was used with Box-Behnken Design (BBD) to design the experiments. The optimum conditions are introduced at the point where initial CO2 capture capacity and deactivation rate constants are as high and as low as possible, respectively. The optimum values of the variables corresponding to the temperature of 50°C, vapor pretreatment time of 9 min, and H2O/CO2 mole ratio of 1. The amounts of initial CO2 capture capacity and deactivation rate constant in the optimum conditions were obtained to be 39.238 mgCO2/gsorbent and 0.416 min-1 , respectively

    Keywords: CO2 capture, Alkali metal carbonate, Operating parameter optimization, ResponseSurface Methodology (RSM), Carbonation reaction, Carbonation kinetics
  • El Hadi Zouaoui, Nibou Djamel, Wan Azlina Wan Ab Karim Ghani, Amokrane Samira Pages 1195-1215

    Due to the adverse effects of Carbon dioxide (CO2) emissions on the environment; various mitigation is regulated to control its emissions. In this study, CO2 adsorption isotherms on NaX or Faujasite X and exchanged zeolites with Li+ (LiX), Zn + (ZnX), Mg2+ (MgX) and K+ (KX) at different temperatures (298, 308, 323, 353, and 362 K) were investigated, using high pressure (3 MPa (30 bar)) thermogravimetric analyzer. The experimental results were then validated using numerous isotherm kinetics models namely Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Elovich, Toth, and Sips. From the study, it was found that the CO2 adsorption isotherms are characterized by a strong increase in low-pressure adsorption and a trend towards a high-pressure limit value Qmax. Specific surface area and pore volume revealed the most significant influent parameters for this study. These findings revealed that both experimental and modeling well correlated with Toth and Sips, gave the best results regardless of the material used.

    Keywords: NaX zeolite, Exchange cations, LiX, KX, MgX, ZnX, CO2 adsorption, Isotherme study
  • Zohreh Honarvar, Mehdi Farhoodi, MohammadReza Khani, Abdorreza Mohammadi, Babak Shokri, Narges Jannatiha, Saeedeh Shojaee Aliabadi Pages 1216-1228

    Carboxymethyl cellulose-coated polypropylene film containing Satureja hortensis Essential Oil (SEO) was developed based on the casting method as a novel composite bilayer film intended for food packaging. Polypropylene films were initially treated with an atmospheric plasma system to improve adhesion properties. The films were incorporated with 1-4% Satureja hortensis essential oil and were characterized for physical (thickness, moisture content, and water solubility), mechanical (Tensile Strength (TS), and elongation at break), optical, as well as Water Vapor . Permeability (WVP), and microstructure (SEM) properties. The antimicrobial activity of the films against five selected bacteria including S. aureus, B. cereus, E. coli, S. Typhimurium, and P. aeruginosa was also examined with direct contact and vapor phase methods. Results showed that higher SEO incorporation dosage led to significantly lower solubility and permeability of bilayer film (P<0.05). Additionally, by increasing SEO concentration, more opaque and stretchable films with less resistance to breakage were obtained. Films incorporated with 2-4% SEO effectively inhibited all tested microorganisms both in direct contact and vapor phase. Results of the present study suggest that SEO incorporated PP/CMC films as a novel structure of biopolymer coatings on common plastics that can be potentially used as active packaging for food products.

    Keywords: Satureja hortensis, Cold plasma, Film, Antimicrobial, Bio-coating
  • Parisa Ghasemi, Mohammad Noshad, Mohammadamin Mehrnia, Hossein Jooyandeh Pages 1229-1237

    In this study, xanthan gum was used to produce cryogel and conversion of cryogel to oleo-gels, and the structural and chemical characteristics of the produced oleo-gels were investigated. Results showed, the produced oleo-gels (COS) contained about 66% oil content and they have able to holding oil at about 60%. The pseudo-second-order model can predict the oil absorption kinetics of cryogels. There was no difference between the number of fatty acids of sunflower oil and COS. 1H NMR and 13C NMR signals, the hydroperoxide (initial oxidation product), and aldehydes (secondary product oxidation) were not revealed in COS. Also, it was observed no exothermic process in the curve in Differential Thermal Analysis (DTA)curve up to 350 °C. AFM is the formation of a uniform, homogeneous, and stable gel network that matched the results of the mechanical properties of the COS.

    Keywords: Cryogel, Oleogel, Xanthan, chemical properties
  • Fateme Talebabadi, Seyed Amin Mirmohammadi, Javad Mokhtari Aliabad, Mohammad Yousefi Pages 1238-1246

    The effects of two types of CBs (N330 and N550) and also two kinds of plasticizer, paraffinic and aromatic oils (PO and AO), on the ultimate characteristics of Natural Rubber (NR) were comparatively studied. The comparative study was performed using rheometric behavior, fatigue life (in tensile mode), aging behavior (168 hours at 70 °C), and compression set analyses. Obtained results showed that there is an optimum ratio of CBN330/CBN550 fillers and also an optimum ratio of PO/AO plasticizers which have the best influence on the properties, especially on the fatigue life. It is found out that synergistic effects of the CBN330 and CBN550 fillers, and also PO and AO plasticizers, due to better dispersion and chain mobility of rubber chains, are the main reason for enhanced outcomes. Another point is that to achieve more superior behavior for this kind of compound, the starting point could be the consequences of this paper. The main goal of this work is to develop an enhanced formula for a NR-based industrial compound.

    Keywords: NR, CB filler, paraffinic oil, aromatic oil, fatigue life, aging
  • Ehsan Taghizadeh Yusefabad, Ahmad Tavasoli, Yahya Zamani Pages 1247-1255

    The borate-doped and non-borated Ni-Mo/ASA-Al2O3 catalysts have been prepared and characterized by the BET, XRD, TGA, and NH3-TPD analysis. The catalyst’s performance was assessed in n-hexadecane hydrocracking using a downflow fixed bed micro-reactor. The stability of the catalysts in the presence of water and coke deposition was examined for the HCK of non-conventional feeds. The obtained results revealed that borate increased the feed percentage conversion from 91.43 to 99.21% compared to the not borated catalyst. This improvement is mostly due to the promotion of the acidic functions by BO3 addition. Results showed that the addition of borate increased the selectivity of light hydrocarbons and light gaseous products slightly (from 4.64 to 8.76%).

    Keywords: Hydrocracking (HCK), Ni-Mo Catalyst, Borate, Discrete lumping model, VGO
  • Harith Al-Moameri, Yusheng Zhao, Rima Ghoreishi, Galen Suppes Pages 1256-1268

    During the foaming process of polyurethane, the surfactant plays a significant role in stabilizing and setting the foam. Simulation this role helps in better predicting the final performance and optimum foam formulation. The relation between the amount of surfactant added to the formulation and the surface tension was studied experimentally by using the capillary rise method to develop a simulation model. This model was aimed to study the critical role of the mechanism that surfactants have in the initial stages of gel formation and through the point where viscosity is high enough to create resistance to support the foams. Bubble sizes were calculated based on the number of nucleation sites, gas generation rate, surface tension, and inner bubble pressure. Since important properties of polyurethane foam, such as compressive strength, closed-cell content, and thermal conductivity can be related to the bubble sizes, this model can be used to predict foam performance and to develop new foam formulations.

    Keywords: Surfactant, Polyurethane, Foam, Collapse, Collision
  • Xiaohong Yang, Weiling Zhu Pages 1269-1276

    Methane is the simplest alkane and the main constituent of natural gas, shale gas, and gas hydrate. Its viscosity has both academic and industrial importance. A new model for the methane viscosity was developed based on the theory of the averaged intermolecular potential field. The derived equations of the model were fitted to 1669 experimental data points in good agreement over the parameter ranges: from 100 to 523 K with the pressure from 0.047 up to 1000 MPa. The new model also comprehensively performed better than the famous samples in comparison. The physical base, good numerical behavior, and better-comparing performance suggest that the model has considerable theoretical significance and practical application potentials.

    Keywords: Viscosity, Methane, Model, Molecular interaction, Molecular potential
  • S. Razani, Mohammad Farsi, MohammadReza Rahimpour, A. Bolhassani Pages 1277-1288

    The main goal of this research is to improve cracking severity in an industrial ethane thermal cracker in a domestic plant. In the first step, the considered cracker is modeled based on the mass and energy balance equations considering a molecular kinetic model. To develop an accurate model, a detailed thermal model is adopted to predict the tube skin temperature. To prove the accuracy of the developed model and considered assumptions, the simulation results are compared with the available plant data. In the next step, a sensitivity analysis is performed to investigate the effects of coil outlet temperature and steam to ethane ratio on the cracking severity factors including ethane conversion and production rate. Based on the results of sensitivity analysis although increasing steam to ethane ratio decreases ethane conversion, it improves ethylene yield. Then, a dynamic optimization problem is formulated to maximize ethylene production and minimize production decay during the process run time considering feed temperature, furnace temperature, and steam to ethane ratio as decision variables. The results show that applying the optimal condition to the system improves ethylene production by about 9.44%.

    Keywords: Ethane cracking, Molecular reaction network, Process modeling, Dynamic optimization
  • Amir Farshi, Ali Jabreili Jolodar Pages 1289-1303

    The uniform atomization of FCC feed causes to produces desirable products like gasoline and decreases undesirable products like coke and dry gas. The atomization process caused the selectivity and efficiency of main products to increase. So Design and manufacturing of optimum atomizer system in FCC process are important. According to this idea, A new twin fluid low-pressure atomizer nozzle including the air-assets type of Nozzle was manufactured in RIPI (Research Institute of Petroleum Industry-NIOC Iran ) from small to large scale. The nozzles sizes were categorized with small to large sizes according to water flow rate(4-50 kg/h). The analysis of spray nozzles pattern and droplet size was made by use of Doppler method with using of Doppler laser analyzers. Many tests were carried out for each size of nozzles, and a flow rate of 50 kg/h a specified nozzle was manufactured and introduced. The general configuration of the nozzle is introduced in this manuscript. The experimental data evaluation for nozzles shows that for a water flow rate of 50kg/hr and air of flowrate 1.4 kg/h, The quantity value of Sauter mean-diameter (D32) and arithmetic diameter (D10) for water droplet particles becomes 150 µm and 50 µm respectively. The following assessment on the pilot-scale will help to develop a new atomizer nozzle on large scale. It shall be mentioned that the development of a new atomizer on a large scale is according to experimental data at the pilot plant scale. Minimization of Sauter means diameter (D32) and arithmetic diameter (D10) for water droplet particles will be variables parameters to optimized atomizer nozzle dimension and configuration.

    Keywords: Nozzle, Fcc, atomization, Laser, Doppler, Low pressure, Fluidized
  • Fahimeh Gharekhani, Mehdi Ardjmand, Ali Vaziri Pages 1304-1314

    In this study, nano-silica oxide's effect as a Drag Reducing Agent (DRA) of water flow in a 12.7 and 25.4 mm galvanized pipe was investigated. The studied parameters include Nano silica oxide concentration, Flow rate, temperature, and tube pipe diameter. To develop the conditions in preparing the Nano-particle on Drag Reduction (DR), nano-particles were provided in the top water-based fluid. To have a comprehensive analysis of process folding conditions, the experiments were carried out with three different drag-reducing concentration agents with three various temperatures and three different flow rates. Moreover, as a new method in this study, the experimental (Drag reduction percent) outputs were evaluated and analyzed using the Artificial neural network which is optimized by a genetic algorithm. In the consequence of algorithm genetic, the highest rate of drag reduction occurred at a horizontal pipeline 12.7 mm, temperature 41.07 °C, and a concentration of 0.628 with a 1441.84 flow rate was 25.84%.

    Keywords: Drag reduction, Pipeline, Nano SiO2, Neural network, Single phase
  • Saber Kouadri, Kateb Samir Pages 1315-1332

    For the aim of evaluating the physical and chemical groundwater quality of six layers (the Lower Devonian, Mio Pliocene, Infero Flux, Cambro Ordovician, Albian, and Zaraitine in Illizi, and to identify the sources of its chemical composition and detect the suitability for drinking and irrigation purposes, 44 samples were collected during tow years 2018-2019 to measure pH, T°, Electrical Conductivity (EC) and Total Dissolved Salts (TDS), major elements concentrations were analyzed in the laboratory. The suitability of groundwater for irrigation and other uses was assessed by determining the sodium adsorption ratio (SAR), Soluble-Sodium Percentage (SSP), Permeability Index (PI), Kelly Index (KI), and Total Hardness (TH) of water samples. The spatial distribution of key parameters was assessed using a GIS-based spatial gridding technique. This analysis indicated that the Zaraitine groundwaters used to have the worst chemical quality, while the Infero Flux, Cambro Ordovician and Albian groundwaters have suitable water for drinking. Based on Sodium Absorption Ratio (SAR), Solubility Sodium Percent (SSP), Kelly Index (KI), Permeability Index (PI), Residual Sodium Carbonate content (RSC), and Magnesium Hazard (MH). we find that the Lower Devonian, the Infero Flux, and Cambro Ordovician have suitable water for irrigation, on the other hand, all of Mio-Pliocene, Albian, and Zaraitine consider as unsuitable for agriculture practice. PCA analyses with the comparison between Lower Devonian wells in Illizi town and Lower Devonian wells in Fadnoun town in groundwater quality confirm that the local environmental conditions are a more important factor for groundwater quality than geographical distribution. Geospatial mapping of hydro-chemical parameters shows that the southeast of Illizi and the western part of Djanet are the best sub-areas for agriculture practice.

    Keywords: Groundwater, GIS, Hydrochemistry, Lower Devonian, Illizi
  • Parinaz Soleimani, Morteza Khoshvaght Aliabadi, Hamed Rashidi, Hooman Bahmanpour Pages 1333-1345

    In this study, Twisted Tape has been investigated to increase the heat transfer in the heaters of the pressure reducing station with a capacity of 1,000 m3 per hour (Golestan Qaleh-Jiq Station). The simulation was performed using Computational Fluid Dynamics (CFD). Simulation results were validated with the data collected from the station, and the simulation results were in good agreement with the data collected from the pressure-reducing station of Qaleh-Jiq, and the deviation from the experimental results was ± 0.1%. Then, three twist ratios of 0.5, 0.25, and 0.167 were considered to study its effect. Changes in speed, temperature, and pressure were analyzed. By inserting Twisted Tape into simple pipes, the length of the coil pipe and the energy consumption of the heaters were reduced by an average of 38% and 22%. This study shows that the efficiency of twisted tapes in the tubes with the highest twist ratio of 0.167 can have the highest efficiency and energy savings.

    Keywords: Heater, Pressure reducing station, Increasing heat transfer, Twisted tape
  • Tannaz Mirhadi Zadi, Mohammad Mohsenzadeh, MohammadMahdi Ghahramani Seno Pages 1346-1363

    Lactic acid bacteria in dairy products are the important bacteriocin-producing group with antibacterial activity effect. The aim of this study was the isolation and molecular identification of bacteriocin-producing enterococci and lactobacilli with a wide range of antibacterial activity. Bacteriocin-producing bacteria were isolated and purified from Iranian native dairy products. The effect of bacteriocins on the Gram-negative and Gram-positive indicator strains, as well as the impact of proteolytic enzymes, pH, and temperature changes on bacteriocin production, were investigated. A total of 431 bacteriocin-producing isolates were characterized from 100 traditional cheese and yoghurt samples. The resulting bacteriocin reduced the growth of these two strains. E. faecium TM81 had both bactericidal and bacteriostatic properties, whereas the L. curvatus TM51 only had bacteriostatic properties. The bacteriocin produced by both strains had the highest antibacterial effect among Gram-positive indicator strains such as Listeria monocytogenes and Bacillus cereus. Because produced bacteriocin (resistant to temperature and pH changes) has a wide range of inhibitory spectra on Gram-positive and Gram-negative bacteria especially pathogenic bacteria, it is recommended to use it as a bio preservative in the food/pharmaceutical industry, and animal feed, as well as an alternative to chemical antibiotics.

    Keywords: Bacteriocin, Enterococcus faecium, Lactobacillus, Bactericidal, Bacteriostatic
  • Xiang Ma, Zhang Kexin, Wang Yonggang, Abdol Ghaffar Ebadi, Mohsen Toughani Pages 1364-1374

    In order to obtain the optimum fermentation medium and conditions for extracellular lipase production by Aspergillus Niger, the fermentation conditions of Aspergillus Niger were optimized by single factor and response surface design, the enzymatic properties of the crude enzyme were also studied. The results showed that the optimum fermentation medium was soluble starch 4%, (NH4)2SO4 0.1%, K2HPO4 0.1%, MgSO4·7H2O 0.05%, peptone 3%, olive oil 1.05%, initial pH 7. The optimal fermentation conditions were 30℃, the sample size was 26 mL/250 mL and the shaking speed was 213 r/min. The optimized lipase activity was 1.55 U/mL, which was 7.75 times of the pre-optimized lipase. It was found that when the pH value of lipase was 7.0, the activity of lipase reached its maximum value of 79.3±6.82%. When the pH value was between 6.0 and 8.0, the activity of lipase could be kept above 60% and the stability was good. At the same time, through the study of the temperature stability of lipase, found that the lipase was stable at 25℃- 35℃, its activity could reach more than 70%. When the enzyme activity reaches the maximum (107.6±9.57%), the temperature was 30℃.

    Keywords: Low-temperature lipase, Conditions of enzyme production, Enzymologicalproperties, Orthogonal experiment, Response surface analysis