Korean Journal of Chemical Engineering (v.31, #5)
Some physical properties and oxidative stability of biodiesel produced from oil seed crops by Fatai Abiola Lateef; Okechukwu Dominic Onukwuli; Uche Chukwu Okoro; Paul Madus Ejikeme; Paul Jere (725-731).
Biodiesel is a cleaner burning fuel than petrodiesel and a suitable replacement in diesel engine. It is produced from renewable sources such as vegetable oils or animal fats. Biodiesel fuel was prepared from castor (CSO), palm kernel (PKO) and groundnut (GNO) oils through alkali transesterification reaction. The biodiesel produced was characterized as alternative diesel fuel. Fuel properties such as specific gravity, viscosity, calorific (combustion) value, The CSO, PKO and GNO were measured to evaluate the storage/oxidative stability of the oils to compare them with commercial petrodiesel. The biodiesel produced had good fuel properties with respect to ASTM D 6751 and EN 14214 specification standards, except that the kinematic viscosity of castor oil biodiesel was too low. The viscosity of castor oil biodiesel at different temperatures was in the range of 4.12–7.21 mm2/s. However, promising results which conformed to the above specification standards were realized when castor oil biodiesel was blended with commercial petrodiesel. At 28 °C the specific gravity recorded for CSO, PKO and GNO biodiesel was higher than the values obtained for petrodiesel. Commercial petrodiesel had the highest oxidative stability than biodiesel produced from CSO, PKO and GNO oils.
Keywords: Biodiesel; Petrodiesel; Transesterification; Fuel Properties
Current trends for the floating liquefied natural gas (FLNG) technologies by Wangyun Won; Sun Keun Lee; Kwangho Choi; Yongchai Kwon (732-743).
Natural gas (NG) and liquefied NG (LNG), which is one trade type of NG, have attracted great attention because their use may alleviate rising concerns about environmental pollution produced by classical fossil fuels and nuclear power plants. However, when gas reserves are located in stranded areas and a portion of the offshore reserves is a significant amount of the total gas reserves, LNG is not suitable because (i) installation of pipelines for the transfer of NG to onshore LNG facilities is expensive and difficult, and (ii) it still has environmental and security problems. As a result, there are many efforts to excavate and monetize these stranded and offshore reserves with floating facilities where offshore liquefaction of NG is possible. Therefore, the development of floating LNG (FLNG) technology is becoming important. Although the FLNG technologies have advantages over conventional LNG technologies, there are still several roadblocks. To overcome the challenges, modular designs related to the main and typical stages of the FLNG process — gas pretreatment, liquefaction and regasification topsides, hulls, mooring, and transfer systems should be enhanced. Regarding FLNG ongoing operations and future plans, there are six nations (Argentina, Brazil, Kuwait, UAE, UK, and USA) operating FLNG, and a variety of FLNG liquefaction projects will be finished soon. Shell and Petrobras are making rapid strides to build FLNG facilities, and Flex LNG, Hoegh LNG, SBM Linde, MODEC, and Saipem are also building their FLNGs. In this review paper, we initially review the LNG concept and compare it with FLNG. In turn, new and typical FLNG technologies are introduced and the main challenges are also explained with insight into how these challenges are overcome. The main market drivers for FLNG industry are also considered.
Keywords: Liquefied Natural Gas; Floating Liquefied Natural Gas; Liquefaction Process; Hull and Mooring Process; Offloading Process
Molecular interactions of graphene with HIV-Vpr, Nef and Gag proteins: A new approach for treating HIV infections by Navanietha Krishnaraj Rathinam; Chandran Saravanan; Pal Parimal; Varalakshmi Perumal; Malliga Perumal (744-747).
Graphene draws considerable attention among biomedical researchers because of its unique physical, chemical and biological properties. The wide applications of graphene in the biomedical arena such as diagnostics, drug immobilization and drug delivery were well documented in the literature. However the therapeutic potential of the graphene towards retroviruses and the interactions of the graphene with receptors/proteins are still unexplored. Herein we report the antagonistic molecular interactions of graphene with the three key target proteins of HIV infections namely HIVVpr, Nef and Gag proteins. The docking investigations were performed to find the binding energy of the graphene ligands to the key target proteins of HIV. The high binding affinity of the graphene to these proteins indicates the antagonistic molecular interaction of graphene to the disease targets. The therapeutic potential of graphene was also studied by changing the size and the number of layers of the graphene. The experimental results confirm the good therapeutic potential of the graphene to combat HIV mediated retroviral infections.
Keywords: Graphene; HIV; Immobilization; Therapeutic Potential; Binding Affinity
Economic analysis of waste recycle process in perhydropolysiloxazane synthesis by Huichan Yun; Seungjong Yeom; Dae Ryook Yang (748-753).
The perhydropolysiloxazane (PHPS) solution has been widely used in the spin-on-dielectric (SOD) process to form silicon oxide layer on a wafer in semiconductor industries. To reduce the whole semiconductor manufacturing cost, the process of PHPS solution production requires high productivity as well as low production cost. A large portion of the PHPS solution production cost is attributed to the large usage of solvents (pyridine and xylene), because more than 20 times of solvents in mass are required to produce a unit mass of high purity PHPS solution. Therefore, we suggest several plausible solvent regeneration processes of organic solvent waste from the PHPS solution production, and their economics is evaluated for comparison.
Keywords: Perhydropolysiloxazane; Recycle; Economic Analysis; Pyridine
Power-law shear-thinning flow around a heated square bluff body under aiding buoyancy at low Reynolds numbers by Neha Sharma; Amit Dhiman; Surendra Kumar (754-771).
Power-law shear-thinning fluid flow over a heated square bluff body is numerically investigated under aiding buoyancy mixed convection at low Reynolds numbers. Semi-explicit finite volume code is developed to solve the governing equations along with the appropriate boundary conditions. Both aiding buoyancy and shear-thinning natures are found to augment the heat transfer rate from the surface of the long square bar. In aiding buoyancy, the total drag coefficient is found to be more for the square cylinder than that of the circular cylinder, whereas the average cylinder Nusselt number for the square cylinder is found to be lower than the circular one on equal side/diameter basis. Maximum augmentation in heat transfer is found to be approximately 20% with respect to forced convection. Finally, a heat transfer correlation is established by using the Colburn heat transfer factor.
Keywords: Square Bluff Body; Non-Newtonian Fluids; Aiding Buoyancy; Drag Coefficients; Nusselt Number; Streamlines; Isotherms and Heat Transfer Enhancement
Predicting the velocity distribution of Rushton turbine impeller in mixing of polymeric liquids using fuzzy neural network models by Ali Aminian; Mansour Jahangiri (772-779).
Velocity profiles are helpful for the confident design of mixing tanks and chemical reactors in mixing processes. A fuzzy model and an artificial neural network have been presented for accurate prediction of velocity distribution of Rushton turbine impeller (RTI) for the mixing of polymeric liquids in the lower transition region: 35
Keywords: Fuzzy; Artificial Neural Network; Velocity Distribution; Rushton Turbine Impeller; Polymeric Liquids
Kinetic model of low temperature coal tar hydrocracking in supercritical gasoline for reducing coke production by Na Chang; Zhaolin Gu (780-784).
To reduce coke production during low temperature coal tar hydrocracking in supercritical gasoline, a lump kinetic model was derived on the basis of catalytic cracking reaction mechanism. Lumps were defined by different reaction properties. Reaction rate constants, indexes of hydrogen to coal tar ratio, indexes of gasoline to coal tar ratio, activation energies, and pre-exponential factors were estimated according to the previous experimental data. The results show that the proposed model could not only predict the product yields successfully, but also provide more information which was useful for any attempts to reduce the coke content and promote the conversion of coal tar to light oils.
Keywords: Low Temperature Coal Tar; Supercritical Gasoline; Hydrocracking; Kinetic Model; Coke
Electrochemical degradation of three reactive dyes using carbon paper cathode modified with carbon nanotubes and their simultaneous determination by partial least square method by Nader Djafarzadeh; Mahdie Safarpour; Alireza Khataee (785-793).
We investigated the treatment of a mixture of three reactive textile dyes (C. I. Reactive Red 195, C. I. Reactive Yellow 84 and C. I. Reactive Blue 69) by electro-Fenton (EF) process using carbon paper cathode modified with carbon nanotubes (CNTs). To study the degradation of mixture of three dyes, a rapid analytical methodology based on recording UV-Vis spectra during the EF process and the data treatment using partial least square (PLS) as a multivariate calibration method was developed. The three reactive dyes were quantified simultaneously despite the overlap of their spectra. Central composite design was used in the modeling and optimization of the electrochemical decolorization process. The independent variables for modeling were initial concentration of three dyes, applied current in the electrolysis system, and reaction time. Results indicated that the optimum applied current value was about 400mA for the EF process. Analysis of variance (ANOVA) showed that predicted responses by CCD match the experimental values logically with the amount of R2 more than 0.92.
Keywords: Electrochemical Treatment; Carbon Nanotubes; Spectrophotometric Determination; Carbon Paper; Central Composite Design
Study of SO2 oxidation over V2O5/activated carbon catalyst using in situ diffuse reflectance infrared Fourier transformation spectroscopy by Wen Jing; Qianqian Guo; Yaqin Hou; Xiaojin Han; Zhanggen Huang (794-800).
The SO2 oxidation over V2O5/AC catalyst was studied using an in situ diffuse reflectance infrared Fourier transformation spectroscopy technique at 120 °C. Results reveal that the surface oxygen groups could neither act as active sites for SO2 oxidation nor supply the oxygen needed for V V ↔V IV redox cycle. The vanadia species and gas phase oxygen are essential for SO2 oxidation. During SO2 oxidation over V2O5/AC, the surface hydroxyl groups involve in the formation of sulfate species. The role of water vapor in flue gas might be to supplement the hydroxyl groups consumed so that the SO2 oxidation could continue.
Keywords: V2O5/AC; In Situ DRIFTS; SO2 Oxidation; Oxygen Groups; Water Vapor
The effects of poly(ethylene glycol) on the low-temperature oxidation reaction of coal as monitored using in situ series diffuse reflectance FTIR by Guolan Dou; Haihui Xin; Deming Wang; Botao Qin; Xiaoxing Zhong (801-806).
In situ series diffuse reflectance FTIR was used to study the effects of poly(ethylene glycol) as a potential chemical additive inhibiting coal oxidation process at low temperatures. Two coals with different volatile content and, different ash percentages were examined following treatment with 5 wt% poly(ethylene glycol) 200. The surfaces of samples both with and without the additive were analyzed at temperature up to 200 °C in air using in situ diffuse reflectance FTIR. The results showed that poly(ethylene glycol) 200 is capable of inhibiting the oxidation of aliphatic moieties such as methyl and methylene groups, and also reducing the quantity of surface hydroxyl groups through reactions that form more stable ether linkages, thus improving the thermal stability of the coal. A mechanism by which the additive interacts with the coal surfaces is proposed.
Keywords: Poly(Ethylene Glycol); Coal Oxidation; In Situ Series Diffuse Reflectance FTIR; Mechanism
Effects of ultrasonic radiation on induction period and nucleation kinetics of sodium sulfate by Guisheng Zeng; Hui Li; Shenglian Luo; Xianyong Wang; Junhong Chen (807-811).
The effects of ultrasound on crystal nucleation and particle size distribution of sodium sulfate were investigated via determining the induction period and particle size. Crystal nucleation parameters and equations for primary nucleation were calculated. The experimental results show that the induction time decreases under the ultrasound irradiation, therefore, we can get a shorter induction period at a higher supersaturation level. Based on these observations, the growth mechanism of sodium sulfate is continuous growth because the value of the surface entropy factor f is smaller than 3. The induction period was observed shorter and particle size was smaller when the ultrasonic radiation time increased. Crystal growth improved with the longer crystallization time.
Keywords: Sodium Sulfate; Crystallization; Ultrasound; Primary Nucleation; Particle Size
Enhanced Zn(II) uptake using zinc imprinted form of novel nanobiosorbent and its application as an antimicrobial agent by Geetanjali Basak; Devlina Das; Nilanjana Das (812-820).
We investigated the use of zinc imprinted of novel nanobiosorbent prepared from Candida rugosa to remove Zn(II) from aqueous solution. The nanobiosorbent was characterized by SEM, FTIR and XRD. Effects of various parameters including pH of the solution, adsorbent dosage, initial Zn(II) ion concentration and contact time on Zn(II) removal by the nanobiosorbents were investigated through batch process. Equilibrium data for Zn(II) removal was fitted to Langmuir isotherm model with an enhanced adsorption capacity of 275.48mg/g for zinc imprinted C. rugosa nanobiosorbent, compared to nonimprinted nanobiosorbent of 172.41 mg/g. Pseudo-second-order kinetic model was best fitted to predict the sorption kinetics for both the nanobiosorbents. AFM study revealed monolayer adsorption with thin film diffusion for Zn(II) removal. The antimicrobial activity of zinc imprinted nanobiosorbent was investigated against pathogenic yeasts viz. Candida albicans and Cryptococcus neoformans using agar well diffusion method.
Keywords: Adsorption Isotherm Models; Candida rugosa ; Nanobiosorbent; Non Imprinted; Zinc Imprinted
Preparation and adsorption characters of Cu(II)-imprinted chitosan/attapulgite polymer by Yingying Shi; Qianghua Zhang; Liangdong Feng; Qingping Xiong; Jing Chen (821-827).
Using attapulgite (ATP) as matrix, chitosan (CS) as functional monomer, and introducing the surface ionimprinting concept, a new Cu(II)-IIP was prepared, and characterized by SEM, XRD and FT-IR. The adsorption of Cu(II) aqueous solution with Cu(II)-IIP was investigated by flame atomic adsorption spectroscopy (FAAS). The polymer has good selectivity for Cu(II) from competitive metal ions, and the selectivity coefficient of Cu(II) relation to Pb(II), Cd(II) was 78.45 and 82.44, respectively. Sorption equilibrium isotherms could be described by Langmuir and Freundlich models; the Freundlich isotherm has shown the best agreement with experimental data, and experimental value of maximum adsorption capacity for Cu(II) was 35.20 mg/g. The obtained thermodynamic parameter (ΔG o , ΔH o , ΔS o ) showed that the Cu(II) adsorption process is a spontaneous and endothermic process. The kinetic data showed that pseudo-second-order kinetic model agrees very well with the dynamic behavior for the sorption of Cu(II) onto Cu(II)-IIP.
Keywords: Attapulgite; Chitosan (CS); Ion-imprinting; Adsorption Isotherms; Selective Recognition; Cu(II)
The effect of dominant ions on solvent extraction of lithium ion from aqueous solution by Gregorius Rionugroho Harvianto; Sang-Gu Jeong; Chang-Sik Ju (828-833).
Solvent extraction of lithium ion using kerosene as solvent is proposed. The extraction of lithium ion using various mixed extractants of β-diketone and neutral ligand in kerosene was performed to find the optimum extractant combination. Considering the extraction efficiency, the optimum extractant combination was 0.02 M TTA and 0.04M TOPO. For the development of lithium extraction from seawater, the effects of dominant ions in seawater were examined in various extraction conditions. The extraction efficiencies generally decreased with the concentration of dominant metallic ions and increased with pH of the aqueous solutions, but Cl− ion showed only minor effect on the efficiency, even up to its concentration in seawater. Except for Mg2+ ion, more than 70% of lithium ions could be extracted at pH 10.6 from aqueous solutions with a dominant ion at its concentration in seawater.
Keywords: Lithium; Dominant Ions; Solvent Extraction; TTA; TOPO
Improved phenol adsorption from aqueous solution using electrically conducting adsorbents by Hafiz Muhammad Anwaar Asghar; Syed Nadir Hussain; Hamed Sattar; Edward Pelham Lindfield Roberts; Nigel Willis Brown (834-840).
The electrically conducting and partially porous graphite based adsorbent (called NyexTM 2000) was tested for its adsorption capacity and electrochemical regeneration ability for the removal of phenol from aqueous solution. Nyex™ 2000 was tested in comparison with Nyex™ 1000, which is currently being used for a number of industrial waste water treatment applications. Nyex™ 1000 exhibited small adsorption capacity of 0.1 mg g−1 for phenol because of having small specific surface area of 1 m2 g−1. In contrast, Nyex™ 2000 with specific surface area of 17 m2 g−1 delivered an adsorption capacity of 0.8 mg g−1, which was eight-fold higher than that of Nyex™ 1000. Nyex™ 2000 was successfully electrochemically regenerated by passing a current of 0.5 A, charge passed of 31 C g−1 for a treatment time of 45 minutes. These electrochemical parameters were comparable to Nyex™ 1000 for which a current of 0.5 A, charge passed of 5 C g−1 for a treatment time of 20 minutes were applied for complete oxidation of adsorbed phenol. The comparatively high charge density was found to be required for Nyex™ 2000, which is justified with its higher adsorption capacity. The FTIR results validated the mineralization of adsorbed phenol into CO2 and H2O except the formation of few by-products, which were in traces when compared with the concentration of phenol removed from aqueous solution. The electrical energy as required for electrochemical oxidation of phenol adsorbed onto Nyex™ 1000 & 2000 was found to be 214 and 196 J mg−1, respectively. The comparatively low energy requirement for electrochemical oxidation using Nyex™ 2000 is consistent with its higher bed electrical conductivity, which is twice that of Nyex™ 1000.
Keywords: Phenol; Improved Adsorption; Bed Electrical Conductivity; Reduced Electrical Cost
Structural and transport properties of polydimethylsiloxane based polyurethane/silica particles mixed matrix membranes for gas separation by Mohammad Ali Semsarzadeh; Behnam Ghalei; Milad Fardi; Mojtaba Esmaeeli; Eshagh Vakili (841-848).
Mixed matrix membranes of synthesized polyurethane (PU) based on toluene diisocyanate (TDI), polydimethylsiloxane (PDMS) and polytetramethylene glycol (PTMG) with polyvinyl alcohol based polar silica particles were prepared by solution casting technique. The homogeneity and thermal properties of the prepared PDMS-PU/silica membranes were characterized using scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The SEM micrographs confirmed the distribution of silica particles in the polymer matrix without agglomerations. Gas permeation properties of membranes with different silica contents were studied for pure CO2, CH4, O2, He and N2 gases. The obtained results indicated the permeability of the condensable and polar CO2 gas was enhanced whereas permeability of other gases decreased upon increasing the silica content of the mixed matrix membranes. The permeability of CO2 and its selectivity over N2 was increased from 68.4 Barrer and 22 in pure PDMS-PU to 96.7 Barrer and 64.4 in the mixed matrix membranes containing 10 wt% of the silica particles.
Keywords: Gas Separation; Membrane; Silica; Polyurethane
Quantitative analysis of the three main genera in effective microorganisms using qPCR by Kihun Ahn; Kwang-Bae Lee; Young-Jun Kim; Yoon-Mo Koo (849-854).
Effective microorganism (EM) cultures have been applied in many research fields such as agriculture, environment and bioremediation. EM is a mixed culture of microorganisms including predominant populations of lactic acid bacteria and yeasts with smaller numbers of photosynthetic bacteria, actinomycetes and other types of microorganisms. Quantitative analysis of EM is requisite for the applications of EM, as its efficiency varies depending on the composition of its main genera of EM. In this study, Rhodobacter sphaeroides, Rhodopseudomonas palustris, Lactobacillus plantarum, and Saccharomyces cerevisiae, the main genera of EM were quantified by quantitative real time polymerase chain reaction, (qRT-PCR). By using selected specific primers, photosynthetic bacteria, lactic acid bacteria and yeast were quantified with high sensitivity and specificity. The ability of viable cell count by qRT-PCR was compared with agar plate cell count, showing linear relationship. Thus, PCR based quantification system is a rapid and highly specific and sensitive tool for the quantification of EM.
Keywords: Effective Microorganisms; qRT-PCR; Quantitative Analysis; Photosynthetic Bacteria; Lactic Acid Bacteria; Yeast
Antimicrobial activity of electrospun polyurethane nanofibers containing composite materials by Rajkumar Nirmala; Duraisamy Kalpana; Rangaswamy Navamathavan; Mira Park; Hak Yong Kim; Soo-Jin Park (855-860).
We report on the preparation and characterization of electrospun polyurethane nanofibers containing silver, cactus, rosin and Scutellariae Radix. The utilized polyurethane nanofibers containing different composite materials were prepared by a simple dip coating method. The morphology, structure and thermal characteristics of as-prepared composite nanofibers were studied by scanning electron microscopy, X-ray diffraction, Fourier transform infrared, Raman spectroscopy and thermogravimetric analysis. The antimicrobial activity of the composite nanofibers was tested against two common food borne pathogenic bacteria, Staphylococcus aureus and Escherichia coli, by the minimum inhibitory concentration method. Our results demonstrated that more pronounced antimicrobial activities were observed for the composite nanofibers. Overall, the fabrication of cheap, stable and effective material with excellent antimicrobial activity can be utilized to inhibit the microbial growth associated with food stuff.
Keywords: Electrospinning; Composite Nanofibers; Antimicrobial
Enhancing lipid productivity of Chlorella vulgaris using oxidative stress by TiO2 nanoparticles by Nam Kyu Kang; Bongsoo Lee; Gang-Guk Choi; Myounghoon Moon; Min S. Park; JitKang Lim; Ji-Won Yang (861-867).
Ability to increase the lipid production in microalgae is one of the heavily sought-after ideas to improve the economic feasibility of microalgae-derived transportation fuels for commercial applications. We used the oxidative stress by TiO2 nanoparticles, a well-known photocatalyst, to induce lipid production in microalgae. Chlorella vulgaris UTEX 265 was cultivated under various concentrations of TiO2 ranging from 0.1 to 5 g/L under UV-A illumination. Maximum specific growth rate was affected in responding to TiO2 concentrations. In the presence of UV-A, chlorophyll concentration was decreased at the highest concentration of TiO2 (5 g/L TiO2) by oxidative stress. The fatty acid ethyl ester (FAME) composition analysis suggested that oxidative stress causes the accumulation and decomposition of lipids. The highest FAME productivity was 18.2 g/L/d under low concentrations of TiO2 (0.1 g/L) and a short induction time (two days). The controlled condition of TiO2/UV-A inducing oxidative stress (0.1 g/L TiO2 and two days induction) could be used to increase the lipid productivity of C. vulgaris UTEX 265. Our results show the possibility of modulating the lipid induction process through oxidative stress with TiO2/UV-A.
Keywords: TiO2 ; Nanoparticles; Oxidative Stress; Chlorella vulgaris ; Fatty Acid Methyl Ester
Factorial design in optimization of the separation of uranium from yellowcake across a hollow fiber supported liquid membrane, with mass transport modeling by Natchanun Leepipatpaiboon; Ura Pancharoen; Niti Sunsandee; Prakorn Ramakul (868-874).
The extraction and stripping of uranium(VI) from other impurity elements in yellowcake was performed simultaneously in one stage by a hollow fiber supported liquid membrane. Uranium ions were selectively extracted from yellowcake using TBP as the extractant, while thorium and some rare earth elements were rejected in the raffinate. The optimization method was carried out using 32 factorial design. The concentration of nitric acid in the feed solution and the concentration of TBP in the liquid membrane were regarded as factors in the optimization. A mass transport model focusing on the boundary layer of the extraction side was also applied. The model can predict the concentration of uranium in the feed tank at different times. The validity of the developed model was statistically evaluated through a comparison with experimental data, and good agreement was obtained.
Keywords: Factorial Design; Hollow Fiber; Liquid Membrane; Uranium; Yellowcake
Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment by Taha Mahdi; Arshad Ahmad; Adnan Ripin; Mohamed Mahmoud Nasef (875-880).
A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100–400W/cm2 and three frequencies ranging from 25–68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm2 and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress.
Keywords: Ultrasonic Wave; Azeotropic Mixtures; Ethyl Acetate/Ethanol; Vapor-liquid Equilibrium; Relative Volatility
Volumetric, ultrasonic and viscometric studies of binary liquid mixures of N-ethylaniline + chlorobenzene, + Bromobeneze, + 1, 2-dichlorobenzene + 1, 3-dichlorobenzene+1, 2, 4-trichlorobenzene at 303.15 and 308.15K by Bitra Jhansi Lakshmi; Manukonda Gowrisankar; Chintala Rambabu; Dittakavi Ramachandran (881-895).
We measured densities (ρ), ultrasonic speeds (u) and viscosities (η) for binary binary mixtures of N-ethylaniline (N-EA) with chlorobenzene (CB), bromobenzene (BB), 1,2-dichlorobenzene (1,2-DCB), 1,3-dichlorobenzene (1,3-DCB), and 1,2,4-trichlorobenzene (1,2,4-TCB) and their pure liquids at 303.15 K and 308.15 K. These experimental data were used to calculate the excess volume (V E ), deviations in ultrasonic speeds (Δu), deviation in isentropic compressibility (Δ κ s ), deviation in intermolecular free length (ΔL f ), deviation in acoustic impedance (ΔZ), deviation in viscosity (Δη) and excess Gibbs free energy of activation of viscous flow (G* E ). The variations of these properties with composition of binary mixtures suggest loss of dipolar association, difference in size and shape of the component molecules, dipole-dipole interactions and hydrogen bonding between unlike molecules. The viscosity data were correlated with Grunberg and Nissan, Katti and Chaudhri, and Hind et al. equations and the results were compared with the experimental results. The excess parameters were fitted to the Redlich-Kister polynomial equation using multi parametric nonlinear regression analysis to derive the binary coefficients and to estimate the standard deviation.
Keywords: Ultrasonic Speed; Viscosity; Excess Molar Volume; N-ethylaniline; Halobenzenes
Preparation of atrazine surface-imprinted material MIP-PSSS/SiO2 and study on its molecule recognition character by Yanbin Li; Tao Chen; Baojiao Gao; Zongwen Qiao (896-904).
By using a novel molecular surface-imprinting technique, “synchronously graft-polymerizing and imprinting” method established by our group, a pesticide molecule surface-imprinted material was prepared successfully for the removal of pesticide residues from water. The micron-sized silica gel particles were first surface-modified with coupling agent γ-aminopropyltrimethoxysilane (AMPS), obtaining the modified particles AMPS-SiO2, onto whose surfaces primary amino groups were introduced. The anionic monomer sodium p-styrenesulfonate (SSS) was used as functional monomer and N,N′-methylenebisacrylamide (MBA) was used as crosslinker. In aqueous solution, the monomer molecules were arranged around the template molecule, atrazine molecule that is an extensively used herbicide, through electrostatic interaction. By initiating of the redox surface-initiating system of -NH2/S2O 8 2− , the graft/cross-linking polymerization of SSS on SiO2 particles and the surface imprinting of atrazine molecule were simultaneously carried out, forming atrazine molecule surface-imprinted material MIP-PSSS/SiO2. With propoxur and pirimicarb, which are also two pesticides as two contrast substances, the recognition performance of the atrazine molecule surface-imprinted material MIP-PSSS/SiO2 was investigated in depth. The experimental results show that MIP-PSSS/SiO2 particles possess special recognition selectivity and excellent binding affinity for atrazine. The binding capacity of atrazine on MIPPSSS/ SiO2 particles can get up to 61mg/g, and relative to propoxur and pirimicarb, the selectivity coefficients of MIPPSSS/ SiO2 for atrazine are 9.69 and 8.79, respectively.
Keywords: Pesticide Residues; Atrazine; Surface Imprinting Technique; Graft Polymerization; Molecule Recognition
Electrochemical properties of Co-less layered transition metal oxide as high energy cathode material for Li-ion batteries by Sungho Choo; Hye Yeon Kim; Dong Young Yoon; Wonchang Choi; Si-Hyung Oh; Jeh Beck Ju; Jang Myoun Ko; Ho Jang; Won Il Cho (905-910).
High energy nickel manganese cobalt oxide materials (HENMC) are one of the most viable cathode materials for a high energy density lithium ion battery (LIB), but they contain expensive and toxic cobalt (Co). We synthesized Co-free high energy nickel manganese oxide cathode materials (HENM) via a solid state reaction method and a coprecipitation method. Their structural and electrochemical properties were comparatively investigated using X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), inductively coupled plasma (ICP), electron probe micro-analysis (EPMA), particle size analysis (PSA) and electrochemical impedance spectroscopy (EIS). The co-precipitated HENM and the solid state fabricated HENM showed high capacities of 250 mAhg−1 and 240 mAhg−1, respectively. It suggests that the solid state fabricated method of HENM would be a good candidate for practical application as well as the co-precipitated one.
Keywords: Li Ion Battery; High Capacity; Cathode; Nickel Manganese Oxide; Solid State Method; Co-precipitation
Synthesis and characterization of cross-linked poly(acrylic acid)-poly(styrene-alt-maleic anhydride) core-shell microcapsule absorbents for cement mortar by Kiseob Hwang; Kiryong Ha (911-917).
We synthesized core-shell microcapsule absorbents with cPAA (cross-linked poly(acrylic acid)) as the core and PSMA (poly(styrene-alt-maleic anhydride)) as the shell by precipitation polymerization, where the shell served to delay the absorption of excess water in cement mortars. To control shell thickness, the cPAA-PSMA capsules were synthesized with core monomer mass to shell monomer mass ratios of 1/0.5, 1/1, and 1/1.5. We observed the hydrolysis of the PSMA polymer in a cement-saturated aqueous solution by Fourier transform infrared (FT-IR) spectroscopy. Furthermore, core-shell structures were observed for 1/1 (cPAA-PSMA #3) and 1/1.5 (cPAA-PSMA #4) core/shell monomer mass ratios, whereas no core-shell structures were observed for the 1/0.5 (cPAA-PSMA #2) microcapsules by transmission electron microscopy (TEM).
Keywords: cPAA-PSMA; Hydrolysis Reaction; Core-shell; Microcapsule; Absorbent