Korean Journal of Chemical Engineering (v.31, #9)

A review of molecular interactions in organic binary mixtures by Firdosa Nabi; Maqsood Ahmad Malik; Christopher Gunaseelan Jesudason; Shaeel Ahmed Al-Thabaiti (1505-1517).
The intention of this review article is to review the knowledge about interactions in organic binary liquid mixtures. Molecular interactions in organic binary liquid mixtures are interesting due to their extensive use in many fields of solution chemistry. The thermodynamics of component molecules present in various systems interacting are particularly interesting because they display fantastic results. Studies of different organic liquid mixtures represent the different modes of interactions prevailing in the component molecules. The number of parameters required describing the properties of a given class of mixtures increases sharply with the number of segment types involved. In recent years, the theoretical and experimental investigations of interactions between unlike molecules have been conveniently carried out using excess thermodynamic functions. The properties of liquid mixtures depend on the forces between molecules and on the nature and volume of these molecules, and change with the composition of the mixtures. This change, in turn, is reflected in the thermodynamic properties of the mixtures. The influence of significant contributions of a chemical, physical and geometrical nature that change excess thermodynamic properties is considered and explained in detail.
Keywords: Thermodynamic Parameters; Organic Mixtures; Intermolecular Interactions; Volumetric Properties; Viscometric Studies; Ultrasonic Properties

Drying performance of a dishwasher with internal air circulation by Seong Woo Jeong; Dong Hyun Lee (1518-1521).
This paper presents an experimental study on the energy flow and drying performance of a dishwasher with internal air circulation. A simple energy flow process was established to determine the energy consumption of a dishwasher with internal air circulation. The drying performance of the dishwasher was determined by evaluating dish wetness. The effect of various performance variables (e.g., final rinse temperature, air circulation flow rate, and fan operation time) on the drying performance and the energy consumption was assessed individually. All tests were performed following a slightly modified EN50242. The energy accumulated in the final rinse step was responsible for evaporating water off dishes. The drying performance increased as the energy consumption increased. More than 1.17 kWh energy was consumed to obtain a drying performance greater than 1.8.
Keywords: Drying; Dishwasher; Energy; Circulation

Design and analysis of multi-stage expander processes for liquefying natural gas by Wonsub Lim; Inkyu Lee; Kwanghee Lee; Byeonggil Lyu; Junghwan Kim; Il Moon (1522-1531).
Multi-stage expander refrigeration cycles were proposed and analyzed in order to develop an efficient natural gas liquefaction process. The proposed dual and cascade expander processes have high efficiency and the potential for larger liquefaction capacity and are suitable for small-scale and offshore natural gas liquefaction systems. While refrigeration cycles of conventional expander processes use pure nitrogen or methane as a refrigerant, the proposed refrigeration cycles use one or more mixtures as refrigerants. Since mixed refrigerants are used, the efficiency of the proposed multi-stage expander processes becomes higher than that of conventional expander processes. However, the proposed liquefaction processes are different from the single mixed refrigerant (SMR) and dual mixed refrigerant (DMR) processes. The proposed processes use mixed refrigerants as a form of gas, while the SMR and DMR processes use mixed refrigerants as a form of gas, liquid- or two-phase flow. Thus, expanders can be employed instead of Joule-Thomson (J-T) valves for refrigerant expansion. Expanders generate useful work, which is supplied to the compressor, while the high-pressure refrigerant is expanded in expanders to reduce its temperature. Various expander refrigeration cycles are presented to confirm their feasibility and estimate the performance of the proposed process. The specific work, composite curves and exergy analysis data are investigated to evaluate the performance of the proposed processes. A lower specific work was achieved to 1,590 kJ/kg in the dual expander process, and 1,460 kJ/kg in the cascade expander process. In addition, the results of exergy analysis revealed that cycle compressors with associated after-coolers and companders are main contributors to total exergy losses in proposed expander processes.
Keywords: Liquefied Natural Gas; Natural Gas Liquefaction; Refrigeration Cycle; Multi-stage Expander; Exergy Analysis

We developed an evaluation module to calculate the carbon capture efficiency of a fluidized bed carbonator via the semi-empirical modeling of the solvent activity of lime particles. Since the solvent activity is affected by regeneration cycle number, reactor temperature, and particle size, two design parameters for the particle activity model, i.e., the characteristic time (t*) and the maximum conversion of particles (X N ), were determined as functions of the carbonator operating conditions by applying the partial least square (PLS) method to experimental data reported in the literature. The validity of the proposed approach was shown, and the effects of reactor design factors on the carbonator performance are discussed by means of appropriate simulation studies.
Keywords: Carbonator; Carbon Capture Efficiency; Semi-empirical Modeling; Partial Least Squares

Experimental study on performance of steam-water injector with central water nozzle arrangement by Wen Jun Li; Dao Tong Chong; Jun Jie Yan; Wei Xiong Chen; Jin Shi Wang (1539-1546).
The steam-water injector (SI) is a simple mechanical device that has been widely used in industry. We did an experimental study to find the influence of physical and geometrical parameters on performance of the SI. The physical parameters studied were steam inlet pressure, water inlet pressure and water inlet temperature. Whereas, the geometrical parameters studied were steam nozzle area ratio, area ratio of steam nozzle to water nozzle and the mixing section converging angle. Pump head was introduced to evaluate the lifting-pressure performance of the SI under different operating and geometrical conditions. Optimal values of steam nozzle area ratio and mixing section converging angle were 1.3 and 11.6° respectively, for the present work, and optimal value of area ratio of steam nozzle to water nozzle increased with increasing water inlet pressure. Two head-capacity curves were introduced to highlight the effect of various physical and geometrical parameters on the performance of SI.
Keywords: Steam-water Injector; Parametric Analysis; Entrainment Ratio; Pump Head; Head-capacity Characteristic

A series of hierarchical mesoporous ZSM-5 zeolites with different morphology were successfully synthesized by the CO2-in-water microemulsion method, and mesoporosity was formed without organotemplate. The different synthesis conditions, including silica alumina molar ratio, stirring time and compressed CO2 pressure, were systematically investigated to discuss the influence of these conditions on the morphology of ZSM-5 zeolite. The resulting samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP) and nitrogen adsorption-desorption measurement. XRD results indicated that compressed CO2 route for the synthesis of MFI zeolites had a fast crystallization rate and good crystallinity. SEM images showed that the ZSM-5 hierarchical mesoporous ZSM-5 zeolite had a uniform chain-like crystal morphology, whereas silicalite-1 displayed a monodisperse crystal morphology. In addition, the nitrogen adsorption-desorption measurement provided sufficient evidence for the presence of hierarchical mesopores in ZSM-5 zeolite.
Keywords: CO2-in-water Microemulsion; Chain-like; Morphology; Hierarchical Mesoporous; ZSM-5

CO2 reforming of methane over Ni-Cu/Al2O3-ZrO2 nanocatalyst : The influence of plasma treatment and process conditions on catalytic properties and performance by Nader Rahemi; Mohammad Haghighi; Ali Akbar Babaluo; Mahdi Fallah Jafari; Somaiyeh Allahyari (1553-1563).
Argon glow discharge plasma was applied for treatment of impregnated Ni-Cu/Al2O3-ZrO2 nanocatalyst. The catalytic performance toward CO2 reforming of methane and the physicochemical properties were investigated by means of GC, BET, XRD, FESEM, TEM, EDX, TG-DTG, XPS and FTIR techniques. The plasma-treated nanocatalyst contains smaller crystal size and high dispersion of NiO. Plasma treatment decreased particle size and plasma high energy species flattened particles on support, increasing the interaction between support and active metals which leads to high catalytic activity. Low temperature activity and H2/CO ratio closer to 1 was observed for plasma-treated nanocatalyst compared to non-treated sample. Moreover, higher product yield and H2/CO ratio was found in CH4/CO2=1 rather than CH4/CO2=1.5. Time on stream test during 1,440 min at 850 °C showed plasma-treated Ni-Cu/Al2O3-ZrO2 nanocatalyst did not experience any deactivation in terms of CH4 and CO2 conversion and H2/CO ratio.
Keywords: Syngas; Dry Reforming; Ni-Cu/Al2O3-ZrO2 ; Non-thermal Plasma

Comparison of CuO-MO x (M=Ce, Zn, Cr and Zr) catalysts in various water-gas shift reactions by Enakonda Linga Reddy; Sang Yoon Kim; Mamilla Jhansi Lakshmi Kishore; Hyun Chan Lee; Dong Hyun Kim (1564-1569).
The water-gas shift (WGS) reaction in the temperature range of 100–350 °C for various feed compositions simulating forward, reverse and real WGS conditions was studied for a series of coprecipitated mixed metal oxide catalysts of 30 wt% of CuO and 70 wt% of metal oxide (CeO2, ZnO, Cr2O3, and ZrO2) as well as for a commercial WGS catalyst (ICI 83-3). The catalysts were characterized using BET, XRD, H2-TPR and N2O dissociation studies. Among the tested catalysts, CuO-Cr2O3 showed the best activity in the forward WGS, while the commercial catalyst was the best catalyst in the real and reverse WGS reactions. The effect of Cu content in the catalyst was also studied and, in the case of the real WGS, 50 wt% CuO-Cr2O3 was more active than 30 wt% CuO-Cr2O3. H2 and CO2 were found to inhibit the forward WGS, decreasing the reaction rate substantially, particularly at temperatures below 200 °C. The inhibition effect varied depending on the tested catalyst and increased with increasing H2 or CO2 concentration. As the inhibition effect was reversible, the competitive adsorption of H2 or CO2 on the active sites has been suggested to be responsible for the effect. The high activity of the commercial catalyst in the H2 rich real WGS could be described by the difference in the H2 inhibition between the catalysts. An easily reducible copper species was found in CuO-Cr2O3 and could be attributed to the high activity in the forward WGS. Keywords:Mixed Metal Oxide Catalysts, Water Gas Shift Reaction, H2 Inhibition, CO2 Inhibition, Copper Chromate Catalyst

Devolatilization characteristics of high volatile coal in a wire mesh reactor by Ho Won Ra; Myung Won Seo; Sang Jun Yoon; Sung Min Yoon; Jae Kwon Kim; Jae Goo Lee; Seung Bin Park (1570-1576).
A wire mesh reactor was used to investigate the devolatilization process of coal particle during entrained flow gasification. Coal from Indonesia East Kalimantan mine, which has high moisture and high volatile matter, was chosen as a sample. Experiments were carried out at the heating rate of 1,000 °C/s and isothermal condition was kept at peak temperature under atmospheric pressure. The char, tar and gas formation characteristics of the coal as well as the composition of the gas components at peak temperatures were determined. The experimental results showed that devolatilization process terminated when temperature reached above 1,100 °C. Most of tar was formed at about 800 °C, while the rate of tar formation decreased gradually as the temperature increased. CH4 was observed at temperatures above 600 °C, whereas H2 was detected above 1,000 °C. The amount of formed gases such as H2, CO, CH4 and C n H m increased as the temperature increased. From the characteristics of devolatilization with residence time, it was concluded that devolatilization terminated within about 0.7 second when the temperature reached 1,000 °C. As the operating temperature in an entrained flow gasifier is higher than ash melting temperature, it is expected that the devolatilization time of high volatile coal should be less than one second in an entrained flow gasifier.
Keywords: Devolatilization; Wire-mesh Reactor; Coal; Char; Gaseous Species

Removal of tylosin from aqueous solution by UV/nano Ag/S2O 8 2− process : Influence of operational parameters and kinetic study by Saeideh Kamali Moghaddam; Mohammadhossein Rasoulifard; Morteza Vahedpour; Mohammadreza Eskandarian (1577-1581).
The present work deals with the photooxidative degradation of tylosin antibiotic (TYL) in the presence of potassium peroxydisulfate (K2S2O8) irradiated by UV-C in the presence of immobilized nano silver. Effects of pH, temperature, peroxydisulfate concentration and immobilized nano silver dosage on the degradation efficiency of TYL were examined. Degradation efficiency was small when the oxidation was carried out in the absence of UV irradiation. Results showed that degradation of TYL increases with temperature, nano Ag and peroxydisulfate initial concentration and decreases with pH. Due to UV/nano Ag/S2O 8 2− processes, more than 90% of TYL can be degraded at room temperature in 35 min at an initial concentration of 50 mgl. Degradation reaction order of TYL by UV/nano Ag/S2O 8 2− process is 1.89. Meanwhile, the initial rates of degradation in UV/nano Ag/S2O 8 2− processes can be described well by the Langmuir-Hinshelwood kinetic model.
Keywords: Advanced Oxidation Processes (AOPs); Kinetics; Tylosin; Nano particle; Peroxydisulfate; UV Irradiation

Adsorption of chromium (VI) on functionalized and non-functionalized carbon nanotubes by Nabisab Mujawar Mubarak; Raj Kogiladas Thines; Noor Rosyidah Sajuni; Ezzat Chan Abdullah; Jaya Narayan Sahu; Poobalan Ganesan; Natesan Subramanian Jayakumar (1582-1591).
We did a comparative study on the adsorption capacity of Cr (VI) between functionalized carbon nanotubes (CNTs) and non-functionalized CNTs. The statistical analysis reveals that the optimum conditions for the highest removal of Cr (VI) are at pH 9, with dosage 0.1 gram, agitation speed and time of 120 rpm and 120 minutes, respectively. For the initial concentration of 1.0 mg/l, the removal efficiency of Cr (VI) using functionalized CNTs was 87.6% and 83% of non-functionalized CNTs. The maximum adsorption capacities of functionalized and non-functionalized CNTs were 2.517 and 2.49 mg/g, respectively. Langmuir and Freundlich models were adopted to study the adsorption isotherm, which provided a K L and K F value of 1.217 L/mg and 18.14 mg1−n L n /g functionalized CNT, while 2.365 L/mg and 2.307 mg1−n L n /g for non-functionalized CNTs. This result proves that functionalized CNTs are a better adsorbent with a higher adsorption capacity compared with the non-functionalized CNTs.
Keywords: CNT; Chromium; Heavy metal; Adsorption; Separation; Functionalization

Highly flame-retarding cotton fabrics with a novel phosphorus/nitrogen intumescent flame retardant by Peihua Zhao; Xinhang Li; Mei Zhang; Shengnan Liu; Wenjun Liang; Yaqing Liu (1592-1597).
A novel phosphorus/nitrogen intumescent flame retardant, namely 6-chloro-4-(diethylamino phosphorate phosphoryl chloride)-2-(sodium 4-aminobenzensulfonate)-1,3,5-triazine (APPCABT), has been synthesized and characterized by elemental analysis, FT-IR, 1H-NMR and 31P{H}-NMR spectroscopies. To investigate the flame-retarding properties of the treated cotton fabrics, APPCABT was applied to the chemical treatment of the cotton fabrics surface. The flame-retarding performance of the treated samples with APPCABT was evaluated by limiting oxygen index (LOI). The thermal degradation behavior of the treated samples was studied using thermogravimetric analysis (TGA). The surface morphology of the treated samples was observed by scanning electron microscopy (SEM). These results show that APPCABT is both an intumescent flame retardant with high efficiency and an excellent char-forming agent for the flame-retarding treatment of cotton fabrics.
Keywords: Phosphorus/Nitrogen; Intumescent Flame Retardant; Triazine; Cotton Fabrics; Flame-retarding Property

Organofunctionalized nanostructured silica SBA-15 with tri(2-aminoethyl)amine tetradentate-amine ligand was synthesized and applied as adsorbent for the removal of Cu2+, Pb2+, and Cd2+ from both synthetic wastewater and real paper mill and electroplating industrial effluents. The prepared materials were characterized by XRD, N2 adsorption-desorption, TGA, and FT-IR analysis. The Tren-SBA-15 was found to be a fast adsorbent for heavy metal ions from single solution with affinity for Cu2+, Pb2+, than for Cd2+ due to the complicated impacts of metal ion electronegativity. The kinetic rate constant decreased with increasing metal ion concentration due to increasing of ion repulsion force. The equilibrium batch experimental data is well described by the Langmuir isotherm. The maximum adsorption capacity was 1.85 mmol g−1 for Cu2+, 1.34 mmol g−1 for Pb2+, and 1.08 mmol g−1 for Cd2+ at the optimized adsorption conditions (pH=4, T=323 K, t=2 h, C0=3 mmol L−1, and adsorbent dose=1 g L−1). All Gibbs energy was negative as expected for spontaneous interactions, and the positive entropic values from 103.7 to 138.7 J mol−1 K−1 also reinforced this favorable adsorption process in heterogeneous system. Experiment with real wastewaters showed that approximately a half fraction of the total amount of studied metal ions was removed within the first cycle of adsorption. Hence, desorption experiments were performed by 0.3M HCl eluent, and Tren-SBA-15 successfully reused for four adsorption/desorption cycles to complete removal of metal ions from real effluents. The regenerated Tren-SBA-15 displayed almost similar adsorption capacity of Cu2+, Pb2+, and Cd2+ even after four recycles. The results suggest that Tren-SBA-15 is a good candidate as an adsorbent in the removal of Cu2+, Pb2+, and Cd2+ from aqueous solutions.
Keywords: SBA-15; Heavy Metal Ion; Removal; Regeneration; Isotherm; Kinetic; Thermodynamics

Simultaneous adsorption of phenol and Cu2+ from aqueous solution by activated carbon/chitosan composite by Qian Liu; Bingchao Yang; Lujie Zhang; Ruihua Huang (1608-1615).
A multifunction adsorbent was synthesized by incorporating AC into CTS, and the ratio of AC to CTS was 1/1. The resultant was called activated carbon (AC)/chitosan (CTS) composite. The simultaneous adsorption of phenol and Cu2+ from aqueous solution onto AC/CTS composite was investigated by a batch procedure. The adsorption processes for both Cu2+ and phenol obeyed the pseudo second-order kinetic model. Phenol was prone to be adsorbed more quickly as compared with Cu2+ when they coexisted in solution. The adsorption behavior of both phenol and Cu2+ followed the Langmuir isotherm. The maximum adsorption capacities of phenol and Cu2+ were 34.19 mg/g and 74.35 mg/g at 293 K, respectively. No obvious competitive adsorption existed between phenol and Cu2+.
Keywords: AC/CTS Composite; Phenol; Cu2+ ; Simultaneous Adsorption

Chitosan-based bioglass composite for bone tissue healing : Oxidative stress status and antiosteoporotic performance in a ovariectomized rat model by Samira Jebahi; Hassane Oudadesse; Gada Ben Saleh; Mongi Saoudi; Sirrar Mesadhi; Tarek Rebai; Hassib Keskes; Abdelfattah el Feki; Hafed el Feki (1616-1623).
Tissue engineering has opened up a new therapeutic avenue promising a revolution in regenerative medicine. Considerable attention has been given to chitosan composite materials and their applications in the field of the bone graft substitutes. We evaluated the antioxidative properties of chitosan-doped bioactive glass (BG-CH) with 17 wt% chitosan, and their applications in the guided bone regeneration. BG-CH was produced by a freeze-drying process and implanted in the femoral condyles of ovariectomized rats. Grafted bone tissues were carefully removed to evaluate the oxidative stress analysis, histomorphometric profile and mineral bone distribution by using inductively coupled plasma optical emission spectrometry (ICP-OES). A significant decrease of thiobarbituric acid-reactive substances (TBARs) was observed after BG-CH implantation. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities significantly increased in ovariectomized group implanted with chitosan-doped bioactive glass (OVXBG-CH) as compared to ovariectomized group implanted with bioactive glass (OVX-BG). The histomorphometric analysis showed that bone/tissue volume (BV/TV), osteoblast number (N.Ob) and osteoblast surface/bone surface (Ob.S/BS) were significantly higher in OVX-BG-CH group than in OVX-BG group. On the other hand, a rise in Ca and P ion concentrations in the implanted microenvironment was shown to lead to the formation/deposition of Ca-P phases. Trace elements such as Sr and Fe were detected in the newly formed bone and involved in bone healing. These results suggested that BG-CH composites could become clinically useful as a therapeutic and implantable material.
Keywords: Chitosan; Bioactive Glass; Graft Biomaterial; Osteoporosis; Antioxidative Profile; Bone Regeneration

Optimization of formic acid hydrolysis of corn cob in xylose production by Tao Zhu; Pingli Li; Xiaowei Wang; Wandian Yang; Heying Chang; Sai Ma (1624-1631).
Dilute acid pretreatment of lignocellulosic material is one of the significant steps in a biorefinery. We used response surface methodology to determine the important factors of formic acid concentration (2%–6% wt%), treatment time (30–150 min), reaction temperature (120–160 °C), and liquid to solid ratio (3–11 mL/g) on dilute acid hydrolysis of corn cob to produce xylose. A xylose yield of 81.6% and selectivity of 15.1 g/g were achieved under the optimal conditions (5% acid concentration, 150 min, 135 °C, and 7 mL/g liquid to solid ratio). The addition of trivalent salts (FeCl3, Fe(NO3)3, and Fe2(SO4)3) to the reaction system enhanced the xylose yield but decreased selectivity. The FeCl3 concentration over 0.75 mol/L had a negative effect on xylose production.
Keywords: Xylose; Formic Acid; Corn Cob; Trivalent Salts; Optimization

Mathematical modeling of supercritical CO2 extraction of essential oil from Echium amoenum seed was carried out. The effect of process variables such as pressure (15, 20, 25 and 30 MPa), temperature (313, 318, 323 and 328 K) and CO2 flow rate (0.6, 0.9, 1.2 and 1.5 ml/min) on the recovery of essential oil extraction was investigated in a series of experiments conducted in a laboratory scale apparatus. The chemical composition of recovered essential oil (fatty acids) was analyzed by GC-FID. The mathematical model was developed utilizing diffusion-controlled regime in the pore and film mass transfer resistances with axial dispersion of the mobile phase at dynamic conditions. Henry’s law was used to describe the equilibrium state of solid and pore fluid phases. The obtained mass transfer equations for the mobile and stationary phases were solved using the numerical explicit method of line, and the modeling predictions of oil extraction recovery were validated via comparison with experimental data. Genetic algorithm (GA) was applied to estimate the optimum value of the Henry constant. Finally, applying the validated model the extraction recovery was investigated as a function of effective variables such as dynamic extraction time and supercritical fluid temperature, pressure and flow rate. A set of optimal operating conditions were determined via modeling parametric analysis to achieve the objective function of maximum recovery.
Keywords: Supercritical Fluid Extraction; Modeling; Echium amoenum Seed; Genetic Algorithm

Improvement of thermal regeneration of spent granular activated carbon using air agent : Application of sintering and deoxygenation by Joon-Hyung Cho; Yoon-Su Kim; Soo-Bin Jeon; Jong-Beom Seo; Jong-Hyeon Jung; Kwang-Joong Oh (1641-1650).
Thermal regeneration of spent granular activated carbon (GAC) using sintering, air-activation, and deoxygenation was investigated to determine the potential of this method for overcoming the drawbacks of thermal regeneration. The conditions for each step were optimized. The physicochemical properties of four regenerated GACs were assessed using BET, SEM, and FT-IR analysis. The suitability of the regenerated GACs for liquid-phase applications was assessed by phenol adsorption, using adsorption isotherms, kinetics, and thermodynamics. Sintering increased the micropore area and volume of regenerated GAC by 19% and 16%, respectively, and controlled excessive burn-off, reducing it by 19%. Air-activation has economic advantages because the reaction time is 80% less than that for steamactivation. Deoxygenation improved the maximum adsorption capacity by 7%, although the number of micropores was reduced. Regenerated GAC by sintering, air-activation, and deoxygenation was best for liquid-phase applications; the results show that these steps help to overcome the drawbacks of thermal regeneration.
Keywords: Thermal Regeneration; Sintering; Air-activation; Deoxygenation; Phenol Adsorption

Novel microporous activated carbon (MAC) with high surface area and pore volume has been synthesized by microwave heating. Iron oxide nanoparticles were loaded into MAC by using Fe(NO3)3·9H2O followed by microwave irradiation for up to five minutes. The surface modified microporous activated carbon was characterized by BET, XRD, SEM and thermogravimetric examinations. Adsorption data of H2 on the unmodified and modified MACs were collected with PCT method for a pressure range up to 120 bar at 303 K. Greater hydrogen adsorption was observed on the carbon adsorbents doped with 1.45 wt% of iron oxide nanoparticle loaded due to the joint properties of hydrogen adsorption on the carbon surface and the spill-over of hydrogen molecules into carbon structures.
Keywords: Microporous Activated Carbon; Iron Oxide Nanoparticles; Microwave Synthesis; Surface Modification; Hydrogen Storage

The vapor-liquid equilibrium of the binary system CO2+1-butyl-3-methylimidazolium nonafluorobutyl sulfonate ([BMIM][NfO]) was measured over a temperature range of 298.2–323.2 K at intervals of 5.0 K for CO2 mole fraction ranging from 0.137 to 0.900 using a high-pressure variable-volume view cell. The Peng-Robinson equation of state was then applied with two-parameter mixing rules over the same range and the results compared with the experimentally obtained data. Increasing the alkyl chain length in perfluorinated sulfonate from methyl to butyl markedly increased the CO2 solubility. To investigate the effect of the number of fluorine atoms in the anion on the phase behavior of imidazolium based ionic liquid, these experimental results were then compared with those reported in previous experimental studies of 1-alkyl-3-methylimidazolium cations and with modeling data. It looks likely that both the number of fluorine atoms in the anion and the presence of S=O groups play an important role in designing CO2-philic molecules.
Keywords: Carbon Dioxide; Phase Equilibrium; 1-Alkyl-3-methylimidazolium Nonafluorobutyl Sulfonate; VLE

Response surface methodology (RSM) and artificial neural network (ANN) were used to evaluate the ultrasound-assisted extraction (UAE) of polyphenols from olive leaves. To investigate the effects of independent parameters on total phenolic content (TPC) in olive leaves, pH (3–11), extraction time (20–60 min), temperature (30–60 °C) and solid/solvent ratio (500 mg/10–20 mL) were selected. RSM and ANN approaches were applied to determine the best possible combinations of these parameters. Box-Behnken design model was chosen for designing the experimental conditions through RSM. The second-order polynomial models gave a satisfactory description of the experimental data. Experimental parameters and responses were used to train the multilayer feed-forward networks with MATLAB. ANN proved to have higher prediction accuracy than that of RSM.
Keywords: Olea europaea ; Polyphenols; Ultrasound-assisted Extraction; Optimization; RSM; Box-Behnken; ANN

High-temperature CO2 sorption on Na2CO3-impregnated layered double hydroxides by Yoon Jae Min; Seok-Min Hong; Sung Hyun Kim; Ki Bong Lee; Sang Goo Jeon (1668-1673).
Layered double hydroxide (LDH), one of representative high-temperature CO2 sorbents, has many advantages, including stable CO2 sorption, fast sorption kinetics, and low regeneration temperature. However, CO2 sorption uptake on LDH is not high enough for practical use; thus it is usually enhanced by impregnation with alkali metals such as K2CO3. In this study, LDH was impregnated with Na2CO3, and analyses based on scanning electron microscopy, N2 gas physisorption, in situ X-ray diffraction, and Fourier transform infrared spectroscopy were carried out to elucidate the characteristics of sorbents and the mechanism of CO2 sorption. Although the surface area of LDH decreased after Na2CO3 impregnation, CO2 sorption uptake was greatly enhanced by the additional basicity of Na2CO3. The crystal structure of Na2CO3 in the Na2CO3-impregnated LDH changed from monoclinic to hexagonal with increasing temperature, and the sorbed-CO2 was stored in the form of carbonate. Thermogravimetric analysis was used to measure CO2 sorption uptake at 200–600 °C. The sample of Na2CO3: LDH=0.35: 1 weight ratio had the largest CO2 sorption uptake among the tested sorbents, and the CO2 sorption uptake tended to increase even after 400 °C.
Keywords: Layered Double Hydroxide; Na2CO3 ; CO2 Sorption; High Temperature

Effect of crosslinker feed content on catalaytic activity of silver nanoparticles fabricated in multiresponsive microgels by Zahoor Hussain Farooqi; Shanza Rauf Khan; Tajamal Hussain; Robina Begum; Kiran Ejaz; Shumaila Majeed; Muhammad Ajmal; Farah Kanwal; Mohammad Siddiq (1674-1680).
We investigated the effect of crosslinking density of poly(N-isopropyl acrylamide-co-acrylic acid) microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels. Multiresponsive poly(N-isopropyl acrylamide-co-acrylic acid) microgels with 2, 4, 6 and 8 mole percentage of N,N-methylene-bis-acrylamide were synthesized by emulsion polymerization. These microgels were characterized by dynamic light scattering and were used as microreactors to synthesize silver nanoparticles. Hybrid system was characterized by ultraviolet-visible spectroscopy. The catalytic activity of hybrid microgels with different crosslinker content was compared by studying the reduction of pnitrophenol as a model reaction. Kinetics of reaction was monitored by spectrophotometry. The value of the apparent rate constant decreases from 0.568 to 0.313min−1, when content of crosslinker are increased from 2 to 8 mole percentage respectively. This decreases in value of apparent rate constant is due to increase in diffusional barrier offered by high crosslinking of polymer network at high mole percentages of N,N-methylene-bis-acrylamide.
Keywords: Microgels; Crosslinking Density; Hybrid Microgels; Catalytic Activity

Rheological characterization of ferrous sulfate-containing water-in-oil-in-water (W1/O/W2) double emulsions by Mozhgan Keyvani; Leila Davarpanah; Farzaneh Vahabzadeh (1681-1694).
With use of response surface methodology (RSM), the W1/O/W2 emulsions containing ferrous sulfate as the inner phase were optimized in terms of stability (ES) and apparent viscosity (μ app ). Curvature display of the responses around their optimal settings was appropriately described using the quadratic polynomial regression model. The non-Newtonian behavior of the test W1/O/W2 emulsions was characterized using the power-law model and change from non-Newtonian to Newtonian (n≃1) was seen in the case of W1/O:W2 ratio equal 20: 80 when the level of Tween-80 was 1 v%. Results of the size distribution pattern showed 60% of the particles were less than 5 μm. Rheological properties of the test W1/O/W2 emulsions as the viscoelastic liquids were analyzed and the results of oscillatory experiments considering shear stress and frequency dependency of G′ and G″ moduli were discussed in terms of the internal microstructure of the emulsions.
Keywords: W1/O/W2 Double Emulsions; Statistical Design; Power-law Model; Viscoelastic Properties; Tween-80

We studied the capability of electrocentrifuge-spinning (ECS) method for generating highly aligned nanofiber. First, the degree of nanofiber alignment (DNA) produced by ECS was compared with that of rotating drum (RD) method and ECS superiority was demonstrated. Then central composite design (CCD) and response surface methodology (RSM) was used for optimization of operating conditions. The critical factors selected for the examination were voltage, polymer concentration, collector diameter and spinneret rotational speed. To design the required experiments at the settings of independent parameters, RSM was applied. A total of 30 experiments were accomplished towards the construction of a quadratic model for target variable. Using this quadratic model, the influence of aforementioned variables was discussed on DNA. The best operating condition for attaining the maximum value of DNA was the applied voltage of 20.19 kV, polymer concentration of 17.44wt%, collector diameter of 40.76 cm, and rotational speed of 2680.10 rpm.
Keywords: Electrocentrifuge-spinning; Highly Aligned Nanofiber; Response Surface Methodology; Optimization