Korean Journal of Chemical Engineering (v.32, #6)
Next generation digital microfluidic technology: Electrophoresis of charged droplets by Do Jin Im (1001-1008).
Contact charging of a conducting droplet in a dielectric medium is introduced as a novel and useful digital microfluidic technology as well as an interesting scientific phenomenon. The history of this phenomenon, starting from original observations to its interpretations and applications, is presented. The basic principle of the droplet contact charging is also presented. Several fundamental aspects of the droplet contact charging from view points of electrochemistry, surface science, electrocoalescence, and electrohydrodynamics are mentioned. Some promising results for future applications and potential features as a next generation digital microfluidic technology are discussed, especially for 3D organ printing. Finally, implications and significance of the proposed technology for chemical engineering community are discussed.
Keywords: Microfluidics; Droplet; Contact Charging; Electrophoresis; Charge Transfer
A strategy of precipitated calcium carbonate (CaCO3) fillers for enhancing the mechanical properties of polypropylene polymers by Thriveni Thenepalli; Ahn Young Jun; Choon Han; Chilakala Ramakrishna; Ji Whan Ahn (1009-1022).
A wide variety of fillers are currently used in more than twenty types of polymer resins, although four of them alone (polypropylene, polyamides, thermoplastic polyesters, and polyvinyl chloride) account for 90% of the market of mineral fillers in plastics. Polypropylene (PP) and PVC dominate the market for calcium carbonate. PP is a versatile reinforcement material that can meet engineering and structural specifications and is widely used for automotive components, home appliances, and industrial applications. Talc, mica, clay, kaolin, wollastonite, calcium carbonates, feldspar, aluminum hydroxide, glass fibers, and natural fibers are commonly used in fillers. Among these, calcium carbonate (both natural and synthetic) is the most abundant and affords the possibility of improved surface finishing, control over the manufacture of products, and increased electric resistance and impact resistance. Meeting the global challenge to reduce the weight of vehicles by using plastics is a significant issue. The current the global plastic and automobile industry cannot survive without fillers, additives, and reinforcements. Polypropylene is a major component of the modern plastic industry, and currently is used in dashboards, wheel covers, and some engine parts in automobiles. This article reports that the use of calcium carbonate fillers with polypropylene is the best choice to enhance the mechanical properties of plastic parts used in automobiles.
Keywords: Carbonation Mechanism; Calcium Carbonates; PCC; Fillers; Polypropylene Polymers; Mechanical Properties; Plastics
A simultaneous microwave-assisted extraction and adsorbent treatment process under acidic conditions for recovery and separation of paclitaxel from plant cell cultures by Gun-Joong Kim; Jin-Hyun Kim (1023-1028).
We have developed a simultaneous microwave-assisted extraction and adsorbent treatment process under acidic conditions to increase the recovery and separation efficiency of the anticancer agent paclitaxel from plant cell culture. The simultaneous process under the conditions of extracting solution (90% aqueous methanol), pH 2.2, extraction time, 6min, ratio of extracting solution to biomass, 1: 1 (v/w), extraction temperature, 40 °C, adsorbent type, sylopute, and ratio of adsorbent to biomass, 0.08: 1 (w/w), facilitated 1.97-fold higher recovery of paclitaxel in a shorter extraction time than the conventional solvent extraction process. In addition, biomass-derived tar compounds were successfully removed by the simultaneous process alone (average removal >97%). Using the simultaneous process, the paclitaxel extraction efficiency was improved, biomass-derived tar compounds were removed, and the purification process was simplified at the same time.
Keywords: Paclitaxel; Microwave-assisted Extraction; Adsorbent Treatment; Simultaneous Process; Acidic Condition
A real-time model based on least squares support vector machines and output bias update for the prediction of NO x emission from coal-fired power plant by Faisal Ahmed; Hyun Jun Cho; Jin Kuk Kim; Noh Uk Seong; Yeong Koo Yeo (1029-1036).
The accurate and reliable real-time estimation of NOx emission is indispensable for the implementation of successful control and optimization of NOx emission from a coal-fired power plant. We apply a real-time update scheme to least squares support vector machines (LSSVM) to build a real-time version for real-time prediction of NOx. Incorporation of LSSVM in the update scheme enhances its generalization ability for long-term predictions. The proposed real-time model based on LSSVM (LSSVM-scheme) is applied to NOx emission process data from a coal-fired power plant in Korea to compare the prediction performance of NOx emission with real-time model based on partial least squares (PLS-scheme). Prediction results show that LSSVM-scheme predicts robustly for a long passage of time with higher accuracy in comparison with PLS-scheme. We also present a user friendly and sophisticated graphical user interface to enhance the convenience to approach the features of real-time LSSVM-scheme.
Keywords: NOx Prediction; Real-time Model; Least Squares Support Vector Machine; Partial Least Squares; Output Bias Update
Mass transfer coefficient of slug flow for organic solvent-aqueous system in a microreactor by Ana Jurinjak Tušek; Iva Anić; Želimir Kurtanjek; Bruno Zelić (1037-1045).
Application of microreactor systems could be the next break-through in the intensification of chemical and biochemical processes. The common flow regime for organic solvent-aqueous phase two-phase systems is a segmented flow. Internal circulations in segments cause high mass transfer and conversion. We analyzed slug flow in seven systems of organic solvents and aqueous phase. To analyze how slug lengths in tested systems depend on linear velocity and physical and chemical properties of used organic solvents, regression models were proposed. It was shown that models based on linearization of approximation by potentials give low correlation for slug length prediction; however, application of an essential nonlinear model of multiple layer perceptron (MLP) neural network gives high correlation with R2=0.9. General sensitivity analysis was applied for the MLP neural network model, which showed that 80% of variance in slug length for the both phases is accounted for the viscosity and density of the organic phases; 10% is accounted by surface tension of the organic phase, while molecular masses and flow rates each account for 5%. For defined geometry of microreactor, mass transfer has been determined by carrying out the neutralization experiment with NaOH where acetic acid diffuses from organic phase (hexane) into aqueous phase. Estimated mass transfer coefficients were in the range k L a=4,652-1,9807 h−1.
Keywords: Liquid-liquid Slug Flow; Regression Model; Mass Transfer Coefficient; Microreactors
Chemical reaction effect on double diffusive convection in porous media with magnetic and variable gravity effects by Akil Jassim Harfash; Ahmed Kadhim Alshara (1046-1059).
We study the problem of double diffusive convective movement of a reacting solute in a viscous incompressible occupying a plane layer in a saturated porous medium and subjected to a vertical magnetic field. The thresholds for linear instability are found and compared to those derived by a global nonlinear energy stability analysis. Then, the accuracy of both the linear instability and global nonlinear energy stability thresholds are tested using a three dimensional simulation. The strong stabilizing effect of gravity field and magnetic field is shown. Moreover, the results support the assertion that the linear theory, in general, is accurate in predicting the onset of convective motion, and thus, regions of stability.
Keywords: Double-diffusive Convection; Chemical Reaction; Magnetic Field; Variable Gravity; Subcritical Instability; Finite Differences
Gas-liquid mass transfer coefficient of methane in bubble column reactor by Jaewon Lee; Muhammad Yasin; Shinyoung Park; In Seop Chang; Kyoung-Su Ha; Eun Yeol Lee; Jinwon Lee; Choongik Kim (1060-1063).
Biological conversion of methane gas has been attracting considerable recent interest. However, methanotropic bioreactor is limited by low solubility of methane gas in aqueous solution. Although a large mass transfer coefficient of methane in water could possibly overcome this limitation, no dissolved methane probe in aqueous environment is commercially available. We have developed a reactor enabling the measurement of aqueous phase methane concentration and mass transfer coefficient (k L a). The feasibility of the new reactor was demonstrated by measuring k L a values as a function of spinning rate of impeller and flow rate of methane gas. Especially, at spinning rate of 300 rpm and flow rate of 3.0 L/min, a large k L a value of 102.9 h−1 was obtained.
Keywords: Methane; Mass Transfer Coefficient; Bubble Column Reactor; Shale Gas
Synthesis of dimethyl carbonate from methyl carbamate and methanol using MCM-41 functionalized with sulfonic acid groups as catalyst by Xianye Qin; Wenbo Zhao; Bing Han; Biao Liu; Peichao Lian; Shuisheng Wu (1064-1068).
The catalytic synthesis of dimethyl carbonate from methyl carbamate and methanol was investigated in a batch reactor. All of the homogeneous Brönsted acid catalysts show favorable catalytic activity. As homogeneous Brönsted acid catalyst is difficult to separate after reaction, it is converted to heterogeneous catalyst by grafting sulfonic acid groups to MCM-41 with three different methods. Their catalytic activity investigation indicated that sulfonic acid groups grafted by sulfonating with chlorosulfonic acid directly showed activity near to that of homogeneous sulfuric acid catalyst. It was further selected as a model catalyst to investigate the effect of acid amount on its catalytic activity. The results indicated that its activity was positively correlated with its acid amount.
Keywords: Dimethyl Carbonate; Methyl Carbamate; Methanol; Sulfonic Acid Groups; MCM-41
Highly stable palladium-loaded TiO2 nanotube array electrode for the electrocatalytic hydrodehalogenation of polychlorinated biphenyls by Chunyue Cui; Juan Wu; Yanjun Xin; Yanhe Han (1069-1074).
Palladized TiO2 nanotube array electrode was prepared for the electrocatalytic hydrodehalogenation (HDH) of 2,4,5-trichlorobiphenyl (2,4,5-PCB). The TiO2 nanotube array electrode was successfully fabricated by anodic oxidation method, and Pd was loaded onto the TiO2 nanotubes by electrochemical deposition. The morphology and structure of the nanotube array electrodes with and without Pd catalysts were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the diameters and lengths of the TiO2 nanotubes were 30–50 nm and 200–400 nm, respectively. The particle size of the Pd was about 12 nm. Electrocatalytic HDH of 2,4,5-PCB with the Pd/TiO2 nanotube array electrode was performed in H-cell reactor. Under a constant potential of -1.0 V, the HDH efficiency of 2,4,5-PCB was 90% and the biphenyl yield was 83% (15% current efficiency) within 180min at the Pd/TiO2 nanotube array electrode. Compared with the Pd/Ti electrode, the Pd/TiO2 nanotube array electrode exhibited higher HDH efficiency and stability. Additionally, the effect of the primary HDH factors was also investigated.
Keywords: TiO2 Nanotube; Electrocatalytic Hydrodehalogenation; Polychlorinated Biphenyls; Palladium
Effect of Pt coverage in Pt-deposited Pd nanostructure electrodes on electrochemical properties by Ah-Reum Park; Young-Woo Lee; Da-Hee Kwak; Kyung-Won Park (1075-1080).
We have fabricated Pt-deposited Pd electrodes via a two-gun sputtering deposition system by separately operating Pd and Pt target as a function of sputtering time of Pt target. For Pt-deposited Pd electrodes (Pd/Pt-X), Pd were first deposited on the substrates at 20 W for 5min, followed by depositing Pt on the Pd-only electrodes as a function of sputtering time (X=1, 3, 5, 7, and 10min) at 20W on the Pt target. As the sputtering time of Pt target increased, the portion of Pt on the Pd electrodes increased, representing an increased coverage of Pt on the Pd electrodes. The Pd/Pt-7 electrode having an optimized Pt coverage exhibits an excellent electrocatalytic activity for methanol oxidation reaction.
Keywords: Sputtering Deposition System; Pt Coverage; Pd Electrode; Methanol Oxidation Reaction; Electrochemistry
Evaluation of biomass component effect on kinetic values for biomass pyrolysis using simplex lattice design by Sasiporn Chayaporn; Panusit Sungsuk; Sasithorn Sunphorka; Prapan Kuchonthara; Pornpote Piumsomboon; Benjapon Chalermsinsuwan (1081-1093).
We evaluated the correlation between the biomass constituents and their kinetic values. To simplify the models and indicate the effect of each constituent, pure biomass components and their mixtures were used as biomass model. The experiments were set up based on simplex-lattice design. The pyrolysis of synthesized biomass was performed by non-isothermal thermogravimetric analyzer. Several kinetic models in the literature, including Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall and analytical method were used to determine kinetic values for each experiment. The generated regression models and predicted kinetic values from those methods were compared. The results obtained from analytical model (for n≠1) showed a good agreement (R2>0.95) with those obtained from experiments. This study also provide contour plots for all cases in order to observe the behavior of biomass pyrolysis at different component ratio.
Keywords: Simplex-lattice Design; Biomass; Pyrolysis; Model; Kinetics
Combination of maghemite and titanium oxide nanoparticles in polyvinyl alcohol-alginate encapsulated beads for cadmium ions removal by Zohreh Majidnia; Ani Idris (1094-1100).
Both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were mixed at various ratios and embedded in polyvinyl alcohol (PVA)-alginate beads. These beads were tested for photocatalytic behavior in eliminating toxic Cd(II) from the aqueous solution. The photocatalytic experiments were performed under sunlight irradiation at various pH, initial feed concentrations and γ-Fe2O3: TiO2 ratios. The recycling attribute of these beads was also investigated. The results revealed that 100% of the Cd(II) was eliminated in 150 minutes at pH 7 under sunlight. It shows that maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the photocatalyst process and reused for at least six times without losing their initial properties.
Keywords: Titanium Oxide Nanoparticles; Magnetic Nanoparticles; Encapsulation; Waste Water; Desorption
Experimental investigation and modeling of industrial oily wastewater treatment using modified polyethersulfone ultrafiltration hollow fiber membranes by Abdolhamid Salahi; Toraj Mohammadi; Reza Mosayebi Behbahani; Mahmood Hemmati (1101-1118).
Hollow fiber membranes were prepared from polyethersulfone/additives/NMP&DMSO system via phase inversion induced by precipitation in non-solvent coagulation bath. The interaction effects of polyethylene-glycol (PEG), propionic-acid (PA), Tween-20, PEG molecular weight and polyvinyl-pyrrolidone (PVP) on morphology and performance of synthesized membranes were investigated. Taguchi method (L16 orthogonal array) was used initially to plan a minimum number of experiments. 32 membranes were synthesized (with two replications) and their permeation flux and TOC rejection properties to oily wastewater treatment were studied. The obtained results indicated that addition of PA to spinning dope decreases flux while it increases TOC rejection of prepared membranes. Also, the result shows that addition of PVP, Tween-20 and PEG content in spinning dope enhances permeation flux while reducing TOC rejection. The obtained results indicated that the synthesized membranes was effective and suitable for treatment of the oily wastewater to achieve up to 92.6, 98.2, and 98.5% removal of TOC, TSS, and OGC, respectively with a flux of 247.19 L/(m2h). Moreover, Hermia’s models were used for permeation flux decline prediction. Experimental data and models predictions were compared. The results showed that there is reasonable agreement between experimental data and the cake layer model followed by the intermediate blocking model.
Keywords: Oily Wastewater; Hollow Fiber Membranes; Non-solvent Additive; Morphology; Taguchi Method; Modeling
Optimization of hexavalent chromium removal from aqueous solution using acid-modified granular activated carbon as adsorbent through response surface methodology by Waseem Daoud; Taghi Ebadi; Ahmad Fahimifar (1119-1128).
Response surface methodology (RSM) was applied to evaluate the effect of the main operational variables, including initial pH, initial chromium ion concentration, bulk density of GAC and time on the removal of hexavalent chromium Cr(VI) from contaminated groundwater by permeable reactive barriers (PRB) with acid-modified granular activated carbon (GAC) as an adsorbent material. The removal rates of Cr(VI) under different values of these parameters were investigated and results indicated high adsorption capacity at low pH and low initial metal ion concentration of Cr(VI), but the bulk density of GAC slightly influenced the process efficiency. According to the ANOVA (analysis of variance) results, the model presents high R2 values of 94.35% for Cr(VI) removal efficiency, which indicates that the accuracy of the polynomial models was good. Also, quadratic regression models with estimated coefficients were developed to describe the pollutant removals.
Keywords: Permeable Reactive Barriers; Polluted Groundwater; Hexavalent Chromium; Granular Activated Carbon; Response Surface Methodology
Adsorption behavior of phenanthrene onto coal-based activated carbon prepared by microwave activation by Xuemin Xiao; Fei Tian; Yujun Yan; Zhilin Wu; Zhansheng Wu; Giancarlo Cravotto (1129-1136).
Coal-based activated carbon (CAC) was prepared from coal produced in Xinjiang of China by microwave activation. CAC was characterized and used as an adsorbent for phenanthrene adsorption. The effects of temperature, adsorption time, CAC amount, initial concentration and pH value of solution on phenanthrene adsorption were studied. The adsorption rate of phenanthrene onto CAC was obtained nearly 100% with initial concentration of 100 mg/L and CAC dosage of 0.3 g at 25 °C. Phenanthrene adsorption was well described with the Langmuir isotherm. The pseudo-second-order model was found to more effectively explain the adsorption kinetics of phenanthrene. The lower temperature was favorable to the adsorption rate and equilibrium adsorption capacity of phenanthrene onto CAC. The thermodynamic parameters ΔH θ , ΔS θ and ΔG θ computed for phenanthrene adsorption onto CAC demonstrate the process was spontaneous, radiative, and entropically driven. Thus, CAC prepared by microwave activation could be effective for removing phenanthrene.
Keywords: Coal-based Activated Carbon; Microwave Activation; Phenanthrene; Adsorption; Kinetics and Thermodynamics
Synthesis, characterization and bactericidal property of chitosan-graft-polyaniline/montmorillonite/ZnO nanocomposite by Alireza Samzadeh-Kermani; Somayeh Miri (1137-1141).
We synthesized the nanocomposite of chitosan-graft-polyaniline/montmorillonite/zinc oxide (CTS-g-PANi/MMT/ZnO). ZnO nanoparticles (NPs) were successfully synthesized from ZnO powder in the Cts/MMT matrix, using traditional method. CTS-g-PANi co-polymer was synthesized in the presence of ammonium peroxydisulfate (APS). The CTS-g-PANi and MMT were used as the natural polymeric stabilizer and the solid support, respectively. The morphology and the particle size of ZnO NPs and synthesized nanocomposite were investigated by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). According to the XRD results, the nanoparticle size was found to be in the range of 22–35 nm. SEM images showed the hexagonal shape of ZnO NPs, which is suitable for the evaluation of antibacterial activity. Finally, the bactericidal property of prepared nanocomposites was also evaluated against the bacteria of Gram positive Staphylococcus aureus (Staph.) and Gram negative Escherichia coli (E. coli), using the paper disc diffusion method.
Keywords: ZnO Nanoparticles; Nanocomposites; Montmorillonite; Chitosan-grafted-polyaniline; Bactericidal
Green synthesis, biochemical and quantum chemical studies of steroidal oximes by Mahboob Alam; Dong-Ung Lee (1142-1150).
Microwave-assisted condensation of steroidal ketones with hydroxylamine under solvent-free condition in presence of basic alumina as solid support yielded the title compounds. The compounds were subjected for their in vitro antimicrobial against a set of pathogenic bacteria and fungi. The 3β-chloro-5α-cholestan-6-one oxime (6) showed highest antimicrobial activity. Steroidal oximes were also screened for their in vitro anthelmintic activity against earthworms. Chloro compound was found to be a more potent anthelmintic agent when compared with albendazole. The in silico docking technique has been applied to ascertain the potential binding sites of the compounds with the pathogenic receptor. The binding modes of a representative compound 6 were accessed on the basis of molecular docking studies. Moreover the structure-antimicrobial activity relationships were studied using some physicochemical and quantum-chemical parameters with GAMESS interface as well as WebMO Job Manager by DFT at B3LYP/6-31G & STO-3G level of theory.
Keywords: Solid State Synthesis; Steroidal Ketone; Antimicrobial; in silico Analysis; Quantum Chemical Analysis
Experimental and theoretical investigation of a new multistage countercurrent melt crystallizer with inclined sieve plates by Shui Wang; Guojing Zhao; Yizhen Du; Yixin Qu (1151-1157).
A new multistage countercurrent melt crystallizer with sieve plates is proposed that combines the advantages of the TNO column crystallizer and the inclined column crystallizer. With the naphthalene-indene solid solution system, the purification process of organic materials in the new multistage countercurrent melt crystallizer with sieve plates under total reflux was investigated. Two of the influencing factors on the separation and purification performance in the new multistage countercurrent melt crystallizer with sieve plates were crystal settling velocity and crystal breakage, which were controlled by stirring speed, the sieve plates, the angle of the sieve plates, the diameter of the pores, particle sedimentation area, and the number of plates. The results of this study show that the optimum stirring speed was determined to be 20 rpm, sieve plates can obviously increase the separation and purification effect, the optimum angle of the sieve plates was determined to be 45o, the optimum diameter of the pores was determined to be 8 mm, the optimum particle sedimentation area was determined to be 0.5 r, and two plates in the crystallizer were shown to be the best.
Keywords: Melt Crystallizer; Sieve Plates; Separation; Purification
Solubility of N-ethylcarbazole in ethanol+petroleum ether mixtures at various temperatures by Wenge Yang; Keyi Wu; Yonghong Hu; Tuan Zhang; Qirun Guo; Shouhai Yang; Ying Shi (1158-1163).
The solubility of N-ethylcarbazole in (ethanol+petroleum ether) binary solvent mixtures was measured with the temperature changing from 280.15 K to 316.15 K. The experimental data matched the solvent/Redlich-Kister (CNIBS/R-K) equation and the Jouyban-Acree equation. Computational results showed the CNIBS/R-K equation was more suitable than the Jouyban-Acree equation. The solution process in the thermodynamic properties, including the Gibbs energy, enthalpy, and entropy, was calculated by the van’t Hoff analysis.
Keywords: N-ethylcarbazole; Solubility; Binary Solvent Mixtures; Thermodynamic Properties
Kinetics of thermal decomposition of ε-hexanitrohexaazaisowurtzitane by TG-DSC-MS-FTIR by Yan-Li Zhu; Ming-Xin Shan; Zhi-Xia Xiao; Jing-Si Wang; Qing-Jie Jiao (1164-1169).
Thermal decomposition of ε-hexanitrohexaazaisowurtzitane (HNIW) was studied by thermogravimetry-differential scanning calorimetry-mass spectrometry-Fourier transform infrared spectroscopy (TG-DSC-MS-FTIR) simultaneous analysis. It has been shown that there is a crystal transition point for ε-HNIW, and only a single decomposition process has been observed for HNIW. The kinetic parameters of thermal decomposition of HNIW were obtained by Kissinger and Flynn-Wall-Ozawa methods, indicating that HNIW has the higher reactivity compared to the other nitramines. The HNIW decomposition mechanism demonstrated by the non-isothermal kinetics conformed to Avrami-Erofeev equation with the factor of nucleus growth of n=1/3 and the conversion degree of α from 0.1 to 0.7. The MS and FTIR analyses indicated that the thermal decomposition of HNIW favors N-N bond cleavage over C-N bond cleavage as the rate determining step.
Keywords: Thermal Decomposition; Hexanitrohexaazaisowurtzitane; Explosive; Chemical Kinetics
Application of cross-linked poly(acrylic acid)-poly(styrene-alt-maleic anhydride) core-shell microcapsule absorbents in cement mortars by Kiseob Hwang; Seoksoo Jang; Yongwook Jung; Seunghan Lee; Jun-Young Lee; KiRyong Ha (1170-1177).
We synthesized core-shell microcapsule absorbents with crosslinked poly(acrylic acid) (PAA) as the core and poly(styrene-alt-maleic anhydride) (cPAA-PSMA) as the shell by the precipitation polymerization method for delayed absorption of excess water in cement mortar. To control the shell thickness, cPAA-PSMA capsules were synthesized with the core-to-shell monomer mass ratios of 1: 0 (cPAA #1), 1: 0.5 (cPAA-PSMA #2), 1: 1 (cPAA-PSMA #3), and 1: 1.5 (cPAA-PSMA #4). The viscosity of the cement paste with cPAA-PSMA #4 absorbent increased slowly until 90minutes after absorbent addition, beyond which it increased rapidly. This suggests that mortars with cPAA-PSMA #4 absorbents can secure up to 90 minutes of working time. Incorporation of 1.0 wt% cPAA-PSMA #4 into cement mortar increased the compressive and flexural strengths by approximately 35% and 22%, respectively, compared to those of cement mortars without absorbents.
Keywords: cPAA-PSMA; Microcapsule; Absorbent; E. Mortar; C. Ccompressive Strength
The role of tetragonal-metal-organic framework-5 loadings with extra ZnO molecule on the gas separation performance of mixed matrix membrane by Mehrzad Arjmandi; Majid Pakizeh; Omid Pirouzram (1178-1187).
The effect of more ZnO molecule in tetragonal structure of MOF-5 than cubic structure on the gas permeation properties of T-MOF-5/polyetherimide mixed matrix membranes was investigated. T-MOF-5 was first successfully synthesized and carefully characterized by XRD, FTIR, SEM and N2 adsorption technique at 77 K. Novel T-MOF-5/PEI MMMs were prepared using solution casting method and characterized by FTIR and SEM. The SEM pictures of the MMMs showed that T-MOF-5 nanocrystals changed the morphology of PEI and exhibited acceptable contacts between the filler particles and the polymer chains. Gas permeation properties of these membranes with different T-MOF-5 contents were studied for pure H2, CO2, CH4 and N2 gases. Permeation measurement showed that the all gases’ permeability, diffusivity and solubility were increased with T-MOF-5 loading. H2 permeability and the ideal selectivity of H2/CO2 and H2/CH4 in MMM with 25 wt% loading of T-MOF-5 nanocrystals were increased. This behavior was attributed to more ZnO molecule in T-MOF-5 structure. The experimental gas permeations through T-MOF-5/PEI nanocomposite with different filler loadings were fitted on Higuchi model. Good agreement between the experimental data and the predicted gas permeability was obtained.
Keywords: Mixed Matrix Membrane; Metal Organic Framework; Tetragonal-MOF-5; Zn; Gas Separation
Photo-catalytic destruction of ethylene using microwave discharge electrodeless lamp by Do-Jin Lee; Young-Kwon Park; Sun-Jae Kim; Heon Lee; Sang-Chul Jung (1188-1193).
A double tube type microwave discharge electrodeless lamp was employed to investigate the photo-catalytic decomposition of ethylene gas, an important VOC species. The anatase TiO2 film photo-catalyst balls prepared by a low pressure metal organic chemical vapor deposition method were used. In addition, the advantages of microwave/UV/TiO2 photo-catalysts hybrid process were analyzed. The removal performance was examined under different conditions with different initial ethylene concentrations, gas residence times and oxygen concentrations. At all microwave powers tested, UV-C exhibited much larger irradiance than UV-A and UV-B. The degradation efficiency of ethylene increased with increasing microwave intensity, with decreasing inlet concentration, and with decreasing reaction gas flow rate. Taking the energy cost into account, residence time should be determined considering inlet concentration, volume of degradation, capacity of devices, and admitted costs. Microwave intensity was shown to be a critical operation variable for the photo-catalytic degradation of ethylene, required to be determined depending on initial ethylene concentration.
Keywords: Ethylene; Microwave; Electrodeless Lamp; TiO2 ; UV
Microstructure and corrosion behavior of electrodeposited nanocrystalline nickel prepared from acetate bath by Ramachandran Sekar; Kopula Kesavan Jagadesh; Giri Nagasamy Kuppusamy Ramesh Bapu (1194-1200).
The present investigation deals with the electrodeposition of nanocrystalline nickel onto mild steel metallic foil from electrolytes containing nickel acetate as the major metal salt. Two different chlorides, potassium chloride and nickel chloride, were tried for two different baths. Potassium citrate was used as buffer for alternate to boric acid. The additives tried were sodium lauryl sulfate as wetting agent, saccharin as primary brightener and 2-butyne 1,4-diol as secondary brightener. These additives are found to improve the hardness, grain size, surface morphology of the electrodeposited nickel films and throwing power of the nickel acetate electrolytes. The nickel films prepared from nickel chloride containing electrolytes showed higher corrosion resistance as compared to potassium chloride containing electrolytes, because the nickel films produced from the nickel chloride electrolytes are compact and possess fine grained structure. The XRD pattern obtained for electrodeposited nickel shows polycrystalline face centered cubic structure. The crystal size was calculated using Scherrer formula. A uniform and pore free surface was observed under SEM analysis.
Keywords: Additive; Electrodeposition; SEM Analysis; Crystal Size; XRD; Corrosion
Synthesis of a novel phosphorus-containing plasticizer based on castor oil and its application for flame retardancy of polyvinyl chloride by Guodong Feng; Puyou Jia; Liqiang Zhang; Lihong Hu; Meng Zhang; Yong-hong Zhou (1201-1206).
A novel flame-retardant plasticizer based on castor oil (FRC) was synthesized, and its potential application for polyvinyl chloride (PVC) was evaluated through the study of torque during melt processing, thermogravimetric analysis (TGA), limiting oxygen index instrument, scanning electron microscope (SEM) and mechanical tests. The results suggested that the FRC has a plasticizing effect in blends with PVC. The addition of FRC resulted in reduction of processing torque, good compatibility, improvement in thermal stability and efficient flame retardant. Torque reduction was observed (33.6%), indicating the reduction of viscosity and the improvement of process. The increase (31.9%) of LOI value indicated that incorporation of FRC system had obviously improved the flame retardant property of PVC blends. The excellent flame retardant properties were obtained by forming an isolation layer on the surface of PVC blends in the process of FRC burning. FRC could improve the thermal ability of PVC blends by enhancing the decomposition temperature of PVC. The performance in all properties of PVC products could be obtained by controlling the formula blends. Therefore, castor oil-based flame retardant plasticizers would appear suitable for a wide range of application.
Keywords: Plasticizer; Castor Oil; Flame-retardant; PVC