Korean Journal of Chemical Engineering (v.31, #12)
Methods for separation of organic and pharmaceutical compounds by different polymer materials by Pravin Ganeshrao Ingole; Neha Pravin Ingole (2109-2123).
The discrimination of enantiomers is a challenging task in separation technology, and using a membrane is most promising for separating enantiomers from racemic mixture. The optical resolution of chiral compounds is of interest to researchers working in a variety of fields from analytical, organic and medicinal chemistry, to pharmaceutics and materials, to process engineering for fabricating pharmaceuticals, agrochemicals, fragrances and foods, and so on. There is considerable demand for separation techniques appropriate for the large-scale resolution of chiral molecules. The separation of chiral compounds using chiral or achiral/non-chiral polymeric membranes with or without chiral selector represents a promising system for future commercial applications. This review focuses on an active field of chiral separation, membrane-based enantioseparation technique, which has potential for large-scale production of singleenantiomers. Enantiomeric separation by membrane processes has been studied using various configurations of liquid and solid polymer membranes. Selectivity and permeability of liquid-membranes is reasonably good because the rate of diffusion of solute molecules is high in liquids but has inferior durability and stability. Solid polymer membranes have inferior permeability because diffusion of solute through solids is slow but quite stable and durable; however, commercial application of membrane technology for optical resolution is yet to be realized. Several chiral separation membranes were prepared from chiral polymers where enantioselectivity was generated from chiral carbons in the main chain. However, it is rather tricky to generate excellent chiral separation membranes from chiral polymers alone, because racemic penetrants mainly encounter the flexible side chains of the membrane polymers.
Keywords: Chiral Separation; Optical Resolution; Enantioselective Polymeric Membranes; Pharmaceutical
Characterizations of furfuryl alcohol oligomer/polymerization catalyzed by homogeneous and heterogeneous acid catalysts by Taejin Kim; Jiwon Jeong; Mohammed Rahman; Elaine Zhu; Devinder Mahajan (2124-2129).
The liquid-phase oligomer/polymerization of furfuryl alcohol (FA) catalyzed by homogeneous and heterogeneous acid catalysts was investigated by Infrared (IR) spectroscopy. At room temperature and 100 °C, FA was not decomposed with metal oxide catalysts except for tungsten oxide, whereas amberlyst and sulfuric acid converted a furfuryl alcohol monomer into oligomer/polymer even at a room temperature. During FA oligomer/polymerization reaction, a strong C=O band observed in the IR spectra provided a diketone structure, which was not observed in the Raman spectroscopy. Based on the FA monomer color changings and IR spectra, tungsten oxide can be possibly applied as a heterogeneous catalyst for controlling the product distribution and avoiding a product separation issue from catalyst.
Keywords: Furfuryl Alcohol; Oligomer/Polymerization; Metal Oxide; Heterogeneous; Homogeneous; Infrared Spectroscopy
Kinetic mechanism of dimethyl ether production process using syngas from integrated gasification combined cycle power plant by Hee-Woo Park; Jin-Kuk Ha; Euy Soo Lee (2130-2135).
In a 1-step synthesis gas-to-dimethyl ether process, synthesis gas is converted into dimethyl ether (DME) in a single reactor. Three reactions are involved in this process: methanol synthesis, methanol dehydration and water gas shift, which form an interesting reaction network. The interplay among these three reactions results in excellent syngas conversion or reactor productivity. The higher syngas conversion or reactor productivity in the syngas-to-DME reaction system, compared to that in the syngas-to-methanol reaction system, is referred to as chemical synergy. This synergy exhibits a strong dependence on the composition of the reactor feed. To demonstrate the extent of this dependence, simulations with adjusted activity for each reaction were performed to reveal the relative rate of each reaction. The results show that the water gas shift reaction is the most rapid, being practically controlled by the equilibrium. Both methanol synthesis and methanol dehydration reactions are kinetically controlled. The role of the dehydration reaction is to remove the equilibrium barrier for the methanol synthesis reaction. However, the role of the water gas shift reaction is more complex; it helps the kinetics of methanol dehydration by keeping the water concentration low, which in turn enhances methanol synthesis. It also readjusts the H2 : CO in the reactor as the reactions proceed. In the CO-rich regime, the water gas shift reaction supplements the limiting reactant and H2, by reacting water with CO. This enhances both the kinetics and thermodynamic driving force of the methanol synthesis reaction. In the H2-rich regime, water gas shift consumes the limiting reactant, CO, which harms both the kinetics and thermodynamics of methanol synthesis. An understanding of these complex roles of the methanol dehydration and water gas shift reactions and of their dependence on the syngas composition explains why the synergy is high in the CO-rich regime, but decreases with the increasing H2 or CO2 content in the reactor feed. The analysis shows that the optimal H2 : CO for the LPDME reactor is around 1-to-1, in good agreement with the results from the simulation. While the 1-to-1 feed provides a good foundation for some process configurations, it does not match the composition of syngas, which typically has a H2 : CO of 3 : 1 or greater.
Keywords: Dimethyl Ether; LPMEOH; LPDME
Modeling and analysis of a syngas cooler with concentric evaporator channels in a coal gasification process by Junho Oh; In-Soo Ye; Sangbin Park; Changkook Ryu; Sung Ku Park (2136-2144).
Coal gasification offers a flexible and efficient conversion of the solid fuel into CO- and H2-rich synthetic gas (syngas) for production of various chemicals and energy products. Since the hot syngas leaving a gasifier contains various impurities such as acidic gases and particulates, it needs to be cooled down for cleaning prior to conversion into the final product. A dedicated heat exchanger called a syngas cooler (SGC) is used to lower the gas temperature while recovering the thermal energy. This study investigated the heat transfer characteristics in a commercial-scale SGC consisting of a series of concentric helical coil channels. First, the detailed flow and heat transfer pattern in the unique heat exchanger were analyzed using computational fluid dynamics (CFD) for various operating loads and fouling conditions. The predicted heat transfer rate was used to derive correlations for Nusselt number for the channel sections of the SGC. Second, a one-dimensional model of the equipment was proposed for fast-response process simulations. In terms of heat transfer rate and gas temperature, the process model showed a reasonable accuracy compared to the CFD results for the tested cases.
Keywords: Coal Gasification; Heat Exchanger; Helical Coil Channel; Process Model; Syngas Cooler
Relative energy stability analysis on the onset of Taylor-Görtler vortices in impulsively accelerating Couette flow by Yong Hwan Kim; Min Chan Kim (2145-2150).
The onset of Taylor-Görtler vortices in impulsively accelerating Couette flows was analyzed by using the energy method. This model considers the growth rate of the kinetic energy of the base state and also that of disturbances. In the present system the primary transient Couette flow is laminar, but for the Reynolds number Re>Re c secondary motion sets in at a certain time. For Re>Re c the dimensionless critical time to mark the onset of vortex instabilities, τ c , is presented as a function of Re. It is found that the predicted τ c -value is much smaller than experimental detection time of first observable secondary motion. Therefore, small disturbances initiated at τ c evidently require some growth period until they are detected experimentally. Since the present system is a rather simple one, the results will be helpful in comparing available stability models.
Keywords: Taylor-Görtler Vortex; Energy Method; Relative Stability
Comparison of spontaneous combustion susceptibility of coal dried by different processes from low-rank coal by Hokyung Choi; Wantaek Jo; Sangdo Kim; Jiho Yoo; Donghyuk Chun; Youngjoon Rhim; Jeonghwan Lim; Sihyun Lee (2151-2156).
We compared the susceptibility to spontaneous combustion of low-rank coals dried by four different processes: flash drying, fluidized bed drying, non-fried carbon briquetting, and coal-oil slurry dewatering. The coals were characterized by FT-IR and XPS analysis. A crossing-point temperature (CPT) was estimated as a comparison criterion of the susceptibility of the coals to spontaneous combustion. O2, CO, and CO2 emissions during the CPT measurement were also compared. The FT-IR and XPS analysis revealed that some of the oxygen functional groups on the surface of the coal were removed when the coal underwent the drying process. This phenomenon was particularly noticeable in the coal dried by oil. Accordingly, the CPT of the coal that went through this drying process was high. Among the samples, the coals dried by oil showed the highest CPT.
Keywords: Low-rank Coal; Crossing-point Temperature; Drying; Spontaneous Combustion; Oxidation
Precursor effect on catalytic properties of Mo-based catalyst for sulfur-resistant methanation by Haiyang Wang; Zhenhua Li; Baowei Wang; Xinbin Ma; Shaodong Qin; Shouli Sun; Qi Sun (2157-2161).
The catalytic activity of Mo-based catalysts prepared from (NH4)6Mo7O24 and (NH4)2MoS4 was compared in the sulfur resistant methanation process. The catalyst using oxide precursor had relatively higher activity than the catalyst using sulfide precursor, and the presulfidation procedure almost had no effect on the catalytic performance of the catalyst using oxide precursor. In view of the characterization results, it could be supposed that the amorphous MoS2 was more active for sulfur-resistant methanation than the crystalline MoS2. The molybdenum sulfides and oxides with lower valence states (Mo4+, Mo5+) could be responsible for the catalytic activity and make a possible contribution to the carbon monoxide methanation in the reaction condition.
Keywords: Sulfur-resistant; Methanation; Precursor; Active Species
Production of elemental sulfur and ammonium thiosulfate by H2S oxidation over Nb2O5 supported on Fe-pillared clay by Moon-Il Kim; Goo-Hwa Lee; Dong-Woo Kim; Dong-Heon Kang; Dae-Won Park (2162-2169).
The catalytic oxidation of hydrogen sulfide (H2S) in the presence of ammonia was studied over niobium pentoxide supported on Fe-pillared clay catalysts (Nb/Fe-PILCs). The synthesized catalysts were characterized by various techniques such as X-ray diffraction, BET method, X-ray photoelectron spectroscopy, temperature-programmed reduction, temperature-programmed desorption of ammonia, and transmission electron microscopy. Catalytic performance studies of the Nb/Fe-PILC catalysts showed that H2S was successfully converted to elemental sulfur and ammonium thiosulfate without any considerable emission of sulfur dioxide. The results show that 3 wt% Nb/Fe-PILC exhibited the highest H2S conversion, which might be due to the uniform dispersion of niobium-oxide species on the Fe-PILC support. Niobium on the fresh Nb/Fe-PILC catalyst was in the +5 oxidation state and it was partially reduced to a lower oxidation state after the reaction.
Keywords: Selective Oxidation; Hydrogen Sulfide; Sulfur; Pillared Clay; Niobium Oxide
Pork lard conversion to biodiesel using a microchannel reactor by Apichat Yamsub; Amaraporn Kaewchada; Attasak Jaree (2170-2176).
Biodiesel was synthesized from pork lard via transesterification using a microchannel reactor. To investigate the effects of operating parameters, including reaction temperature (55–65 °C), residence time (5–20 s), methanol-to-oil molar ratio (4.5 : 1 to 9 : 1), and catalyst concentration (0.7–1.3 wt%), a series of full factorial experiments with a complete replicate were conducted. Results were statistically analyzed using MINITAB with the significance level of 0.05. A quadratic model was proposed for the prediction of %FAME from the specified operating conditions. High %FAME was obtained at low residence time due to the small size of droplets in the microchannel reactor. Evidence of droplets supported the presence of mass transfer limitation in this system. The optimal operating conditions provided %FAME of 95.41% were as follows: methanol-to-oil ratio of 6 : 1, temperature of 65 °C, residence time of 5 s, and KOH concentration of 1.3%w/w.
Keywords: Biodiesel; Microchannel Reactor; Pork Lard; Transesterification
Effect of kinetic hydrate inhibitor and liquid hydrocarbon on the heterogeneous segregation and deposition of gas hydrate particles by Kyuchul Shin; Jakyung Kim; Yutaek Seo; Seong-Pil Kang (2177-2182).
Segregation and deposition of hydrate particles observed in flowloop experiments are required to be investigated more thoroughly to understand the hydrate plugging mechanism in offshore flowlines. We used natural gas as gas phase and selected three different systems as liquid phase, which are pure water only, kinetic hydrate inhibitor added aqueous solution, and water+decane mixture, respectively. Hydrate formation process including onset and growth was studied by measuring the pressure, temperature, and torque changes in high-pressure autoclave. The obtained results suggest that poly-vinyl caprolactam (PVCap) solution shows elongated growth period than pure water until distinct torque change is observed, which also indicates the suppressing effect of PVCap on the growth of hydrate crystals. However, the presence of decane as continuous liquid phase enhances the deposition of hydrate particles on the wall. The torque change with conversion to hydrate used in this study is found to be useful to classify the hydrate formation process into three different regions.
Keywords: Gas Hydrates; Particle Agglomeration; Kinetic Hydrate Inhibitor; Flow Assurance; Offshore Gas Fields
Role of copper pyrovanadate as heterogeneous photo-Fenton like catalyst for the degradation of neutral red and azure-B: An eco-friendly approach by Sangeeta Kalal; Narendra Pal Singh Chauhan; Noopur Ameta; Rakshit Ameta; Sudhish Kumar; Pinki Bala Punjabi (2183-2191).
The heterogeneous photo-Fenton like process is a green chemical pathway. It has an edge over conventional Fenton and photo-Fenton processes as it does not require the removal of ferrous/ferric ions in the form of sludge. We prepeared copper pyrovanadate or Volborthite (Cu3V2(OH)2O7∙2H2O) composite photocatalyst by wet chemical method. The photocatalyst was characterized by SEM, XRD, IR, TGA/DSC, EDX and BET. Experiments demonstrated that catalyst could effectively catalyze degradation of neutral red and azure-B in presence of H2O2 in visible light. Moreover, the photo-Fenton-like catalytic activity of Cu3V2(OH)2O7∙2H2O was much higher than CuO and V2O5, when used alone as photocatalyst. The effect of variation of different parameters, i.e., pH, amount of photocatalyst, concentration of dye, amount of H2O2 and light intensity was also investigated. The degradation was well fitted under pseudo-first-order reaction with a rate constant of 2.081×10−4 sec−1 and 3.876×10−4 sec−1 for neutral red and azure-B, respectively. Quality parameters of dye solutions before and after photo-Fenton degradation were also determined. A tentative mechanism involving •OH radical as an oxidant has been proposed. The high catalytic activity may be due to the Cu3V2(OH)2O7∙2H2O shell, which not only increased the surface hydroxyl groups, but also enhanced the interfacial electron transfer. The catalyst has been found to possess good recyclability.
Keywords: Advanced Oxidation Processes; Heterogeneous; Photo-Fenton; Neutral Red; Azure-B; Mechanism
Adsorption of methyl orange using self-assembled porous microspheres of poly(o-chloroaniline) by Muhammad Naveed Anjum; Khalid Mahmood Zia; Lihua Zhu; Haroon-ur-Rashid; Mirza Nadeem Ahmad; Mohammad Zuber; Heqing Tang (2192-2197).
Self-assembled hollow microspheres poly(o-chloroaniline) (POC) have been synthesized by simple oxidative polymerization of o-chloroaniline using camphor-sulfonic acid (CSA) as dopant acid and ammonium persulfate (APS) as oxidant. The POC microspheres were characterized by means of FTIR, XRD and SEM analysis. Adsorption characteristics of POC spheres were studied by using methyl orange (MO) as adsorbate. It was found that adsorption of MO by POC was better described by pseudo-second-order kinetics than any other kinetic model, such as the pseudo-first-order and intra-particle diffusion models. Langmuir adsorption isotherm model was the best to fit experimental data. The results showed that hollow microspheres of POC can be used as novel and low-cost adsorbent for removal of organic dye from waste water.
Keywords: Adsorption; Methyl Orange; Hollow Microspheres; Poly(o-chloroaniline)
Coffee waste as potential adsorbent for the removal of basic dyes from aqueous solution by Ridha Lafi; Anouar ben Fradj; Amor Hafiane; B. H. Hameed (2198-2206).
We evaluated the adsorption performance of coffee waste (CW), collected from coffee shops, for the removal of two basic dyes, toluidine blue (TB) and crystal violet (CV), from aqueous solutions. Batch adsorption experiments were conducted under different conditions including contact time, initial concentration of dye, pH, sorbent dosage and temperature. The Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherms were tested to examine the adsorption behavior. The equilibrium data were well fitted by Langmuir isotherm model. The kinetic study indicates that adsorption follows the pseudo second-order model. The maximum adsorption capacity was found to be as high as 142.5 mg/g for TB and 125 mg/g for CV, which makes CW a prospective adsorbent for the removal of basic dyes from aqueous solution.
Keywords: Adsorption; Coffee Waste; Basic Dyes; Isotherm; Kinetics
Abatement of Cr (VI) from wastewater using a new adsorbent, cantaloupe peel: Taguchi L16 orthogonal array optimization by Bahman Ramavandi; Ghorban Asgari; Javad Faradmal; Soleyman Sahebi; Babak Roshani (2207-2214).
Taguchi orthogonal design was applied for multivariate optimization of Cr (VI) abatement by cantaloupe peel powder (CPP), as a novel adsorbent, from industrial wastewater in a batch mode. Effective factors in the adsorption process, such as temperature, CPP dose, Cr (VI) concentration, wastewater pH, and contact time, were considered using an L16 orthogonal array design. The best conditions for adsorbing of Cr (VI) were determined by the Taguchi method and desirability approach as pH of 2, chromium concentration of 100mg/L, contact time of 5min, CPP dosage of 0.5 g/L, and wastewater temperature of 25 °C. Analysis of variance results indicated that the pH was the most important variable influencing the chromium removal percentage, and its contribution value was obtained 45.01%. The Langmuir model proved best fit for the experimental data and maximum adsorption capacity of Cr (VI) onto CPP was obtained 166.25mg/g. The final part of the study includes an examination of the CPP through an analysis of the removal of chromium from real industrial wastewater. It can be concluded that the CPP presents a promising and efficient alternative for eliminating of Cr (VI) from industrial wastewaters.
Keywords: Cantaloupe Peel; Cr (VI); Industrial Wastewater; Optimization; Taguchi Method
Purification and deodorizing activity against methyl mercaptan of polyphenol oxidase from lettuce (Lactuca sativa L.) by Yang-Bong Lee; Eui-Cheol Shin; Seon-Bong Kim (2215-2220).
Polyphenol oxidase (PPO) from lettuce was isolated to determine the effect of its involvement in deodorizing activity by measuring the reduction in the amount of methyl mercaptan. The enzyme and deodorizing activities of PPO from lettuce were evaluated using different substrates, temperatures, and pH levels. The molecular weight of purified PPO from lettuce was estimated to be 56 kDa. The PPO and deodorizing activities were highest at the pH range of 6.0 at 20 °C and 5.0 at 10 °C, respectively. The deodorizing and PPO activities were greater for ortho-diphenols than monophenols and polyphenol. Especially, (+)-catechin, one of ortho-diphenols was shown in 100% PPO activity, and chlorogenic acid and caffeic acid eliminated a methylmercaptan odor up to 95%. The deodorizing activity was highest in Cu2+ solution, but ascorbic acid and sodium hydrosulfite inhibited deodorizing activity. These basic data will provide an optimum manufacturing condition for commercial products using lettuce extracts.
Keywords: Deodorizing Activity; Methyl Mercaptan; Iceberg Lettuce; Polyphenol Oxidase; Polyphenols
Characterization, stability, and antioxidant activity of Salicornia herbaciea seed oil by Dubok Choi; Geum-Sook Lim; Yu Lan Piao; On-You Choi; Ki-An Cho; Choon-Bae Park; Young-Cheol Chang; Young-Il Song; Myung-Koo Lee; Hoon Cho (2221-2228).
We investigated the physicochemical properties, chemical composition, stability and antioxidant activity from seed oil of Salicornia herbaciea grown in Korea. The density, refractive index, acid value, peroxide value, iodine value, saponification value, and unsaponifiable matter of oil were 0.91mg/mL, 1.48 at 20 °C, 1.89mg KOH/g oil, 10.20 mEq/kg oil, 1.08 g I/g oil, 216.21 mg KOH/g oil, and 2.60%, respectively. The major fatty acids were linoleic acid (43.73%), oleic acid (19.81%), arachidic acid (13.52%), and palmitic acid (11.84%), respectively. The oil contained high levels of α-tocopherol (249.2 mg/kg oil), followed by δ-tocopherol (89.3 mg/kg), and γ-tocopherol (75.6 mg/kg oil). The oil was found to have high levels of β-sitosterol (94.5mg/kg oil) and stigmasterol (65.7mg/kg oil), respectively. The total phenol, chlorophyll and β-carotene content of oil was 15.2, 94.5, and 8.2 mg/kg oil, respectively. The oil had good oxidative stability during 60 days of storage in a dark area at 50 °C. The maximum degradation rates of the oil were observed at 242.3 °C (9.5%/min), 382.6 °C (5.2%/min), and 440.7 °C (1.3%/min), respectively, where the rate of the weight decrease increased to a maximum up to this point. The ABTS radical scavenging activity of the oil was increased from 50.2 to 71.8% when the oil concentration extracted by methanol was increased from 100 to 300 μg/mL. This study suggests that S. herbaciea seed oil has potential use in functional foods, cosmetics or pharmaceuticals.
Keywords: Salicornia herbaciea ; Seed Oil; Fatty Acids; Stability; Antioxidant Activity
Investigation of operating parameters of water extraction processes for improving bio-oil quality by Boonyawan Yoosuk; Jiraporn Boonpo; Parncheewa Udomsap; Sittha Sukkasi (2229-2236).
Water extraction of slow-pyrolysis bio-oil, in order to improve its quality, was investigated in terms of different schemes and operating parameters. The water extraction separated the bio-oil into two phases: an aqueous phase and an organic water-insoluble fraction (or “pyrolytic lignin”). Properties of the pyrolytic lignin extracted with different extraction schemes and conditions were characterized and compared. The results showed that the water temperature and stirring time did not significantly affect the pyrolytic lignin’s properties. The water : bio-oil ratio, however, could remarkably reduce the pyrolytic lignin’s acidity. Given the findings, an effective time- and resource-saving extraction scheme with appropriate operating conditions could be devised. The resulted pyrolytic lignin, which was essentially the “upgraded” bio-oil, had notably lower acidity, higher heating value, and more stability than the starting bio-oil, due to the removal of alcohols, ketones, carboxylic acids, sugars, ethers, as well as reactive compounds by the water extraction.
Keywords: Pyrolysis; Bio-oil; Water Extraction; Upgrading; Pyrolytic Lignin
Adsorption of vanadium(V) from acidic solutions by using octylamine functionalized magnetite nanoparticles as a novel adsorbent by Masoome Parijaee; Mohammad Noaparast; Kamal Saberyan; Sayyed Ziaadin Shafaie-Tonkaboni (2237-2244).
Adsorption of vanadium(V) from acidic solutions was investigated by using octylamine functionalized magnetite nanoparticles as a novel adsorbent of vanadium. Batch experiments were conducted to determine the effects of initial pH, nanoparticles to octylamine weight ratio, amount of adsorbent, stirring time and initial vanadium(V) concentration in aqueous solution on adsorption efficiency. The adsorption was highly pH dependent, and the optimal pH was 3.2. The weight ratio of magnetite nanoparticles to octylamine was studied in optimum pH, and the best result was 3 : 2. More than 88% of vanadium(V) in solution was removed by 38.4 mg of adsorbent. In kinetics studies, the adsorption equilibrium could be achieved within 10minutes, and the experimental data were well fitted by the pseudosecond-order model. Comparison of Langmuir and Freundlich isotherm models indicated a better fit of Langmuir model to the adsorption of vanadium(V) and the mono-layer adsorption capacity for vanadium(V) was 25.707 mg g−1.
Keywords: Vanadium (V); Magnetite; Octylamine; Magnetic Nanoparticles; Isotherm Studies
Excess properties and viscous flow thermodynamics of the binary system 1,2-ethanediamine+triethylene glycol at T=(298.15, 303.15, 308.15, and 313.15) K for CO2 capture by Yan Chang; Jianbin Zhang; Qiang Li; Lihua Li; Bo Guo; Tianxiang Zhao (2245-2250).
Liquid densities and viscosities are reported for the binary system of 1,2-ethanediamine (EDA)+triethylene glycol (TEG) at T=(298.15, 303.15, 308.15, and 313.15) K. Densities were measured using a capillary pycnometer and viscosities were determined using an Ubbelohde capillary viscometer. The experimental results are compared with data published in the literatures. Based on the density data and kinematic viscosity data, excess molar volumes (V m E ) and deviation in kinematic viscosity (Δν) were calculated and the calculated results were fitted to a Redlich-Kister equation to obtain the coefficients and estimate the standard deviations between the experimental and calculated quantities. The values of V m E are negative in the whole composition range, whereas the values of Δν are positive over the major composition range. From kinematic viscosity data, Gibbs energies of activation of viscous flow (ΔG*), enthalpy of activation for viscous flow (ΔH*), and entropy of activation for the viscous flow (ΔS*) were also calculated.
Keywords: Density; Viscosity; Excess Molar Volume; Viscous Flow Thermodynamics
Development of electrolyte SAFT-HR equation of state for single electrolyte solutions by Azam Najafloo; Farzaneh Feyzi; Ali Taghi Zoghi (2251-2260).
The explicit version of the mean spherical approximation (MSA) is added to the SAFT-HR equation of state (EoS) to model aqueous alkali halide solutions. The proposed electrolyte equation of state (eEoS) has two parameters per each ion. Two methods are in common use for calculating ion parameters: ion-based and salt-based. In this work, the electrolyte parameters are obtained for 61 single electrolyte solutions using salt-based method. Using this approach, mean ionic activity coefficients of the 61 aqueous electrolyte systems were modeled with overall average absolute relative percent deviation (AAD%) of 3.91. Also, for testing the ability of the model in terms of ionic parameters, six salts (NaCl, NaBr, NaI, KCl, KBr and KI) were studied using ion-based method. The liquid densities, osmotic coefficients and salt mean ionic activity coefficients of 6 aqueous electrolyte solutions were modeled with overall AAD% of 0.68, 2.28 and 0.96, respectively.
Keywords: Electrolyte Solutions; SAFT-HR EoS; Mean Spherical Approximation
Application of cloud point methodology to the determination of nitroanilines in natural water by Huiqi Wang; Haochen Jiang; Naizhong Song; Xiaoting Liu; Qiong Jia (2261-2265).
We developed a methodology based on cloud point extraction (CPE) for the determination of three nitroanilines, p-nitroaniline (PNAL), m-nitroaniline (MNAL), and o-nitroaniline (ONAL). The CPE methodology was coupled with high performance liquid chromatography determinations. Tergitol 15-S-7, an environmentally friendly nonionic surfactant, was employed as the surfactant. To obtain the optimum extraction efficiency, several experimental factors were investigated, including sample pH, salt concentration, surfactant concentration, equilibration temperature, and incubation time. Under the optimized experimental conditions, the linear ranges were 0.06–1, 0.03–1, and 0.01–1 μg mL−1 for PNAL, MNAL, and ONAL, respectively. The limits of detection (LOD) for PNAL, MNAL, and ONAL were 0.013, 0.005, and 0.002 μg mL−1 with the intraday and interday relative standard deviations less than 3.1% and 6.5%. The present method proved to be simple, green, rapid, sensitive, and competitive when used for the determination of nitroanilines in water samples, and the accuracy was assessed through recovery experiments.
Keywords: Cloud Point Extraction; Nitroanilines; High Performance Liquid Chromatography; Tergitol 15-S-7
Synthesis and adsorption properties of carbamazepine imprinted polymer by dispersion polymerization in supercritical carbon dioxide by Jae-Cheon Lee; Chang-Ryong Kim; Hun-Soo Byun (2266-2273).
We synthesized molecularly imprinted polymers (MIPs) which can selectively separate carbamazepine (CMZ) as a pharmaceutically active compound by using supercritical fluid technology in supercritical carbon dioxide (scCO2), and also evaluated the adsorption properties of the prepared CMZ imprinted polymers (CMZ-IPs). CMZIPs is prepared with methacrylic acid (MAA) as a functional monomer, CMZ as a template, and ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent. The binding characteristics of CMZ-IPs are evaluated using equilibrium binding experiments. The adsorption ability in aqueous solution of CMZ-IPs was investigated by HPLC analysis, measuring the adsorbed amounts for the template and its structural analogue, the selectivity factor (α), and the imprinting-induced promotion of binding (IPB). The adsorption properties with the change of pH and temperature of aqueous solution were also examined. The results of the evaluation analysis indicate that the prepared CMZ-IPs have high selectivity (102, 94, 75 and 44 µmol/g) and separation abilities.
Keywords: Molecularly Imprinted Polymers (MIPs); Carbamazepine; Supercritical Fluid Carbon Dioxide; Adsorption Properties; Separation Technology
Etch characteristics of CoFeB thin films and magnetic tunnel junction stacks in a H2O/CH3OH plasma by Su Min Hwang; Adrian Garay; Il Hoon Lee; Chee Won Chung (2274-2279).
Inductively coupled plasma reactive ion etching of CoFeB thin films and magnetic tunnel junction (MTJ) stacks with nanometer-sized patterns was performed using H2O/CH3OH gas mixture. As the CH3OH concentration in H2O/CH3OH increased, the etch rate of both the CoFeB films and MTJ stacks increased, but the etch selectivity decreased while the etch profiles of CoFeB films and MTJ stacks improved. Field emission transmission electron microscopy observation clearly revealed that the MTJ stacks etched at 75% CH3OH in H2O/CH3OH gas mixture showed a good etch profile without any redeposition and a high degree of anisotropy. These results indicate that there were some chemical reactions between CH X in H2O/CH3OH plasma and the films that comprise the MTJ stacks, such as CoFeB magnetic films. It was confirmed that H2O/CH3OH gas mixture could be a good etch gas in attaining a high etch rate and high degree of anisotropy in the etch profile.
Keywords: CoFeB; Magnetic Tunnel Junction Stack; Inductively Coupled Plasma Reactive Ion Etching; H2O/CH3OH
Cosmetic effects of Prunus padus bark extract by Danbi Hwang; Hyunwoo Kim; Hyejin Shin; Hyangli Jeong; Jinhong Kim; Donguk Kim (2280-2285).
Prunus padus bark extract was tested for use as a natural cosmetic ingredient. P. padus bark extract was obtained by hot water extraction and succeeding maturing processes. Total polyphenol and flavonoid concentrations were measured, and safety test (cell toxicity test), efficacy tests (antioxidation, antiwrinkle, whitening), and temperature stability tests were conducted in experiments. Total polyphenol and flavonoid concentrations were 714.7±0.5 mg/g and 72.1±2.2mg/g, respectively. Compared with other natural antioxidants, polyphenol concentration in P. padus bark extract was extremely high. P. padus bark extract showed lower cell toxicity in 100–500 μg/ml concentration by MTT assay. P. padus bark extract indicated 71% DPPH free radical scavenging activity (antioxidation), 36% elastase inhibition (antiwrinkle), and 38% tyrosinase inhibition (whitening) at 350 μg/ml, respectively. W/O/W lotion formulation containing 1% P. padus extract was prepared and stability tests were done to see variations in cosmetic properties. Viscosity, pH, particle size, and appearance of lotion containing 1% P. padus extract maintained stable condition for 28 days. Particle size of lotions showed homogeneous 362–426 nm ranges during stability tests. From this study, P. padus bark extract displayed strong possibility as a natural antioxidative cosmetic agent.
Keywords: Prunus padus ; Cosmetic Agent; Antioxidant; W/O/W Emulsion; Stability
One-pot synthesis of 5-hydroxymethylfurfural directly from cottonseed hull biomass using chromium (III) chloride in ionic liquid by Shui Wang; Yizhen Du; Ping Zhang; Xiaowei Cheng; Yixin Qu (2286-2290).
We studied the direct synthesis of 5-hydroxymethylfurfural (5-HMF) from cottonseed hull biomass under acid condition in one-pot. The influence of HCl dosage, reaction temperature and time, CrCl3·6H2O amount, and cottonseed hull loading on the yield of 5-HMF was investigated. As a result, a 5-HMF yield up to 51% was obtained using 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) catalyzed with chromium (III) chloride at 130 °C for 2 h. The [Bmim]Cl/CrCl3·6H2O/HCl system was found to have high activity and selectivity for the dehydration of cellulose into 5-hydroxymethylfurfural. This work provides a low cost, environment-friendly and energy-efficient process to directly convert raw biomass into bio-fuels and chemicals.
Keywords: Cottonseed Hull; 5-Hydroxymethylfurfural; Furfural; Chromium (III) Chloride; [BMIM]Cl