Showing papers in "Journal of Chemical Engineering of Japan in 2004"

CO2 Absorption by Lithium Silicate at Room Temperature

Abstract: Lithium silicate has been studied mainly as a CO2 absorbent at high temperatures of around 773 K. It has recently been observed that lithium silicate also absorbs atmospheric CO2 at room temperature. In this study, lithium silicate absorbent was packed in an absorption column and the effectiveness of this column was confirmed. Based on this result, the effectiveness of lithium silicate in absorbing atmospheric CO2 at room temperature was evaluated. It was found that humidity promoted absorption. This mechanism was examined and ascribed to the relationship between the water content in lithium silicate and CO2 absorption. In addition, the effectiveness of lithium silicate absorbent was compared with that of a commercially available absorbent (soda lime) under conditions of controlled humidity, and the superiority of lithium silicate was confirmed.

Sub-critical Water Hydrolysis Treatment for Waste Squid Entrails and Production of Amino Acids, Organic Acids, and Fatty Acids

Abstract: The study presented in this paper is focused on processing squid wastes by using sub-critical water extraction and hydrolysis to produce valuable substances. Using a small-scale batch reactor (9.0 cm 3 ), squid entrails were treated with sub- and supercritical water without oxidants. Reaction conditions involved temperatures of 443-673 K, pressures 0.792-30.0 MPa, and reaction times 1-50 minutes. Fat and oil were extracted into sub-critical water very efficiently, and soluble proteins, organic acids, and amino acids were produced In the aqueous phase by a hydrolysis reaction. Even in the short reaction time of 5 min, more than 99% of solid were converted to those products in the temperature, which was higher than 550 K. Results showed a maximum total yield of sixteen amino acids of 0.1031 kg/kg dry entrails at 473 K (5 min), and a maximum total yield of seven organic acids of 0.055 kg/kg dry entrails at 553 K (40 min). Also the oil extracted with hexane included useful fatty acids. Our experimental results indicated that the sub-critical water treatment method is very efficient for converting waste squid entrails to valuable materials as resources for many other industries.

The Photocurrent of Dye-Sensitized Solar Cells Enhanced by the Surface Plasmon Resonance

Abstract: To evaluate the effect of the surface plasmon resonance of Ag nanoparticles on dye-sensitized solar cells, we measured the photocurrent of electrochemical cells using dense dye-adsorbed TiO2 thin films with and without Ag nanoparticles at different adsorbed-dye concentrations. At lower dye concentrations, the photocurrent of the cells with Ag was found to be enhanced by the effect of the surface plasmon resonance compared to that of the cells without Ag. On the other hand, the photocurrent of the cells with Ag decreased at higher dye concentrations, which was caused by increased trap levels and band-edge fluctuations with Ag incorporation. It is revealed that the control of the structure and quantity of Ag particles is important to apply the surface plasmon resonance effect to dye-sensitized solar cells.

Hydrogen Production by Steam Reforming of Methanol

Abstract: Steam reforming of methanol, CH 3 OH + H 2 O → 3H 2 + CO 2 , was carried out over Cu/ZnO and various supported group 8-10 metal catalysts. Over Cu/ZnO catalysts prepared by a coprecipitation method, the steam reforming of methanol occurs with high selectivity regardless of composition of the catalyst and structure of the precursor (aurichalcite, malachite, hydrozincite or their mixture). The Cu/ZnO catalysts prepared from the aurichalcite precursor are more active than those prepared from other precursors. By contrast, over supported group 8-10 metal catalysts, such as supported Pd, Pt, Co, Ni, Rh, Ir and Ru catalysts, hydrogen and carbon monoxide are predominantly produced by decomposition of methanol, CH 3 OH → 2H 2 + CO. The selectivity for the steam reforming is lower than those over Cu/ZnO catalysts. However, the selectivity for the steam reforming is markedly improved upon the previous reduction of Pd/ZnO, Pd/Ga 2 O 3 , and Pd/In 2 O 3 at higher temperatures. Upon addition of Zn to the supported Pd catalysts, the selectivity for the steam reforming and the rate of hydrogen formation are markedly increased. Over Zn modified Pd/CeO 2 catalyst, the selectivity attains to 99.0%, being comparable to Cu/ZnO catalysts. Combined results with temperature programmed reduction, XRD, XPS and AES measurements revealed that PdZn alloy was formed by the previous reduction of Pd/ZnO or Zn modified pd/CeO 2 catalyst. Catalytic functions of Pd are greatly modified upon the formation of PdZn alloys.

Product Quality Estimation and Operating Condition Monitoring for Industrial Ethylene Fractionator

Abstract: In this industry–university collaboration, a soft sensor for measuring a key product quality and an on-line monitoring system for testing the validity of the soft sensor were developed to realize highly efficient operation of the ethylene production plant. To estimate impurity concentration in the ethylene product from on-line measured process variables, a dynamic partial least squares (PLS) model was developed. The developed soft sensor can estimate the product quality very well, but it does not function well when the process is operated under conditions that have never been observed before. Therefore, an on-line monitoring system was developed to judge whether the soft sensor is reliable or not. The monitoring system is based on the dynamic PLS model designed for estimating the product quality. The present research provides a PLS-based framework for developing a soft sensor and monitoring its validity on-line. In addition, simple rules were established for checking the performance of a process gas chromatograph by combining the soft sensor and the monitoring system. The soft sensor and the monitoring system have functioned successfully in the industrial ethylene plant.

Micromixing in a Rotating Packed Bed

Abstract: A parallel-competing chemical test reaction was performed in a Higee liquid/liquid system to evaluate the micromixing efficiency. According to the experimental results, it indicated that increasing rotational speed and liquid flow rate could intensify micromixing effectively. The micromixing efficiency in a Higee system was shown to be higher than other reported types of mixing devices, and the centrifugal force was also effective in enhancing micromixing when the liquid viscosity increased. An empirical correlation was then obtained, implying that the characteristic mixing time was proportional to the rotational speed to the power of –0.64. To investigate the relation between micromixing and mass transfer, an experiment of deoxygenation was performed. It is found that mass transfer resistance decreased as the micromixing efficiency increased.

Removal of VOCs from Gaseous Streams in a High-Voidage Rotating Packed Bed

Abstract: This work examined the feasibility of applying the rotating packed bed (RPB) with the high-voidage packing to the removal of volatile organics compounds (VOCs) from gaseous streams. Isopropyl alcohol (IPA) and ethyl acetate (EA) were used as the model VOCs herein. The overall volumetric gas-side mass transfer coefficient (KGa) was observed as a function of rotor speed, gas flow rate and liquid flow rate. The obtained results demonstrated that the high-voidage RPB could achieve mass transfer efficiencies equivalent to the low-voidage RPB. Consequently, the high-voidage RPB has a great potential in the reduction of VOCs from the exhausted gases. An empirical correlation was also proposed, implying that the KGa value varied with the centrifugal force to the 0.326 power.

Evaluation of Ozone Treated Fish Waste Oil as a Fuel for Transportation

Abstract: In recent years, with increasing global warming and fossil fuel resource depletion, biodiesel has become a possible alternative to diesel fuel from the viewpoint of emission control. Biodiesel fuel is produced from renewable natural bio-sources and is easily combustible, and therefore various processes involved in biodiesel fuel production have been recently developed. In the present study, we produced biodiesel transportation fuel from fish waste oil using ozone treatments and evaluated its properties as an alternative to diesel fuel. Ozone treatment lowered the flash point of the produced fuel, resulting in easy combustibility. Quantitative changes in the amounts of fatty acids that form triglycerides and hydrocarbons in three oil samples (untreated and ozone treated) were also shown. Total ion chromatograms produced from gas chromatography mass spectrometry (GC/MS) revealed that the fatty acid compositions of fish waste oil decompose giving rise to hydrocarbons. The ozone treated fish waste oil was considered to be a suitable alternative to diesel fuel from the viewpoint of fuel quality and exhaust gases.

Molecular Simulation Study on Adsorption and Diffusion Behavior of Ethanol/Water Molecules in NaA Zeolite Crystal

Abstract: Molecular simulations have been performed on adsorption equilibria and diffusivities of pure and mixed-gases of ethanol/water in micropores of an NaA zeolite crystal by using the μVT-ensemble orientational-bias Monte Carlo and the NVT-ensemble equilibrium molecular dynamics techniques. The temperature and the total pressure were set at 378 K and 0.1 MPa respectively for comparison with the data of vapor permeation of a corresponding system. Adsorption equilibrium selectivity of water to ethanol was found to increase with an increasing ethanol composition in the gas phase, which was qualitatively in agreement with the experimental permselectivity, though the latter was three orders of magnitude higher than the first. The diffusivity of water in the zeolite was found to be in the region of 3.9–7.9 × 10–10 m2/s while the ethanol molecules were confined in the α-cage and did not go through the window during a simulation period of 3 ns, which indicated that the diffusivity of ethanol might be much smaller than that of water. Therefore, it is concluded that the high permselectivity of water through an NaA zeolite membrane is ascribed to the cooperation of two factors: the high adsorption selectivity and the high diffusivity of water. It is also noted that the selective adsorption of water may be important for preventing the blockage by ethanol molecules at the entrance and inside of the membrane.

Optimal Design of a Fin-type Silica Gel Tube Module in the Silica Gel/Water Adsorption Heat Pump

Abstract: The silica gel/water adsorption heat pump (AHP) with an adsorber consisted of fin-type silica gel tube (FST) modules was proposed for producing cold heat energy with temperature below 288 K. Considering the performance of such a silica gel/water AHP, the heat and mass transfer characteristics in the FST module were studied by the proposed model, and the optimal sizes (fin pitch and fin length) of the FST module for obtaining maximum cold heat output were decided. It is found that an AHP using the optimized FST module in the adsorber can produce 2 times cold heat output as much as the AHP using the previous FST module (Fujisawa et al., 2002).

Characterization of performances of the wall-type reactor with plate-fin type nickel catalyst prepared by electroless plating, for methanol decomposition

Abstract: A catalytic reactor requires an effective exchange of heat energy, a quick load response and a downsized dimension, as is seen for the reformer system that generates hydrogen for fuel cells. A wall-type reactor, which metallic wall is directly catalyzed, is attracting interest as a reactor that would satisfies such demands. This research studied the performance of reaction and heat transfer of a rectangular wall reactor, for decomposing methanol to hydrogen and carbon monoxide. The reactor consists of alternating reaction channels with a plate-fin type nickel catalyst prepared by electroless plating between heat medium channels. Furthermore, the dynamic response of the reactor was also examined when the flow rate of feed gas was rapidly changed.The temperature profiles in the rectangular wall reactor demonstrated that the reactor effectively supplies heat energy to reaction zone, even under the reaction condition with a large amount of energy consumption. In addition, the performance of the reactor to handle the feeding material depended on the channel height and the shape of the plate fins inserted into the reaction channel. The performance increased as the height decreased and when serrated-type fins were used. The overall coefficient of heat transfer estimated from the temperature distribution in the reactor suggests that the performance increased because the heat conductivity of the reactor improved as a result of changing the channel height. The heat conductivity of effluent gas stabilized within a few seconds from when the flow rate of feed gas was changed instantaneously. The time required for the reaction to attain steady state was short. The results suggest that the constructed reactor responds to load fluctuation quickly.

New PCMs Prepared from Erythritol-Polyalcohols Mixtures for Latent Heat Storage between 80 and 100°C

Abstract: The present study is concerned with preparation of erythritol–polyalcohols mixtures as PCMs, which may be applicable for heat storage in the temperature range between 80 and 100°C for a hot water supply system. The melting/solidification temperature was adjusted by adding polyalcohols such as trimethylolethane (TME), 2-ethyl-2-methyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 1,4-butanediol, 2-amino-1,3-propanediol and trimethylolpropane (TMP), to erythritol.It was found that a new PCM(86) composed of 40% erythritol and 60% TME melted at 86.1 and 97.8°C with a latent heat of 246 kJ/kg. Another PCM(80) composed of 90% PCM(86) and 10% TMP melted at 80.0 and 95.0°C with a latent heat of 231 kJ/kg. These new PCM(86) and PCM(80) derived from erythritol were considered potentially applicable for a hot water supply system, in terms of their relatively large heat storing capacities and specific heats, as well as high thermal conductivities.

Effect of Nonionic Head Group Size on the Formation of Worm-Like Micelles in Mixed Nonionic/Cationic Surfactant Aqueous Systems

Abstract: The phase behavior, microstructure and rheological properties of mixtures of polyoxyethylene type nonionic surfactants (C12EOn, n = 0–4) and alkyltrimethylammonium bromide cationic surfactants in water were investigated. Upon addition of C12EO3 to the aqueous cationic system at high surfactant concentration, both the interfacial curvature of aggregates and the effective cross-sectional area per surfactant molecule, aS, decrease, resulting in a hexagonal-lamellar liquid crystal phase transition. This effect becomes more pronounced as the alkyl chain-length of the cationic surfactant increases. At low surfactant concentration, addition of nonionic amphiphile to micellar solution above a particular concentration, C*, induces a rapid unidimensional micellar growth, and particularly in CTAB systems viscoelastic micellar solutions of entangled wormlike micelles are formed. With successive addition of the nonionic amphiphile ultimately a micellar to lamellar phase transformation occurs. Rheological measurements within the Wm-phase show that with decreasing EO chain-length, C* also decreases and viscosity increases more swiftly with increasing concentration of nonionic amphiphile, suggesting a rapid micellar growth. This is attributed to the decrease in aS, as predicted by a simple geometrical model.

Surfactant Drag Reduction Caused by a Cationic Surfactant with Excess Addition of Counter-ions

Abstract: Surfactant drag reduction is a promising technology to reduce the pumping power of district heating–cooling systems. Many investigations have been reported to give a clear prospect of the drag-reducing phenomenon. However, the mechanism of surfactant drag reduction and the microstructure of surfactant micelles are still left unknown. This study aims to provide an experimental evidence of the effect of counter-ions on the micelle structure and the surfactant drag reduction in a pipe flow. The present authors have been investigating the surfactant drag reduction with a cationic surfactant with suitable counter-ions (sodium salicylate). The effect of the molar ratio of the counter-ion to the cationic surfactant is discussed using the experimental results on the drag reduction in a turbulent pipe flow, on the micelle size and on the shear thinning–thickening viscosity. These experimental results suggest that a new drag-reducing state exists at very high molar ratios of the counter-ion to the surfactant. This new state gives a remarkable drag reduction, but shows very weak viscoelasticity. The optimum molar ratio to cause a strong viscoelasticity is (surfactant):(counter-ion) = 1:1.5, but at higher molar ratios, the elongational viscosity decreases, while high drag reduction effectiveness is kept. The micelle structure could be changed at higher counter-ion molar ratio, but this new structure may also be effective for drag reduction.

Preparation of Molecular Imprinted Thermosensitive Gel Adsorbents and Adsorption/Desorption Properties of Heavy Metal Ions by Temperature Swing

Abstract: A gel adsorbent which adsorbs and/or desorbs specific heavy metal ions selectively by temperature swing was prepared by copolymerizing the chelating monomer, N-(4-vinyl)benzyl ethylenediamine (Vb-EDA) with N-isopropylacrylamide (NIPA) as thermosensitive component by using the molecule imprinting technique. Copper ion, Cu(II) was selected as a target ion in imprinting. The adsorption amount of Cu(II) ions on imprinted gel depended on the temperature, and the maximum amount was obtained at a specific temperature where the size of gel network corresponds to that memorized in the preparation of gel. The adsorption amount depended on the gel composition, namely, the concentrations of NIPA and cross-linker. The adsorption amount increased linearly with the increasing Vb-EDA content in the gel, and the slope was almost 1/2. This implies that one Cu(II) ion coordinates with two molecules of Vb-EDA. The adsorption amount was well described by the Langmuir isotherm formula. The adsorption and desorption could be done repeatedly by temperature swing. Furthermore, the selective adsorption of Cu(II) ions was confirmed by comparing the adsorption amounts of other metal ions, Ni(II), Zn(II) and Mn(II).

Oxidation of NO to NO2 Using the Ozonization Method for the Improvement of Selective Catalytic Reduction

Abstract: Removal of nitrogen oxides (NOx) using an ozonization and catalysis hybrid process was investigated. The role of the ozonization in the hybrid process is to increase NO2 content by oxidizing a part of NO, thereby leading to improving the performance of the catalytic reduction. It was found that the rate of the oxidation of NO to NO2 in the ozonization chamber was very fast in a temperature range of 443 to 473 K, almost completed in a few tens of milliseconds. The decomposition of ozone into molecular oxygen was not significant, and one mole of ozone approximately reacted with one mole of NO. In addition, a kinetic study revealed that the ozonization method produces a negligible amount of byproducts such as NO3 and N2O5. The effect of the content of NO2 in NOx on the catalytic reduction efficiency was examined by adjusting the degree of NO oxidation in the ozonization chamber. The selective reduction of NOx to N2 by a monolithic catalyst (V2O5-WO3/TiO2) was largely enhanced when the content of NO2 was equal to that of NO, indicating that the mixture of NO and NO2 reacts faster than NO.

Kinetics of Water-Gas Shift Reaction in Supercritical Water

Abstract: The kinetics of the water gas shift reaction was investigated in supercritical water using the Raman spectroscopic method for in situ quantitative measurement of reactants and relevant products in a stopped flow type reactor. The reaction proceeded according to the stoichiometric reaction as CO + H2O → CO2 + H2, whose rate was first order on the concentration of CO. The dependence on the reactant water was 1.5 ± 0.1 in the water density range from 4 to 25 mol dm–3 at a temperature of 380°C. The steady state concentration of formic acid was in the order of 10–4 against the initial concentration of CO and dependent on a 1.2 ± 0.3 order on the water density. These findings evidence that the rate determining step of the water gas shift reaction is the formation process of formic acid, which subsequently dissociates to CO2 + H2 at a much larger reaction rate. The slightly larger dependence than unity on the water density in the reaction rate as well as in the steady state concentration of the intermediate formic acid suggests that the transition state structure of the formic acid formation process resembles a certain kind of complex formed between a CO molecule and several water molecules such as suggested by Melius et al. (1990) by ab initio calculations.

Fluid and Solids Flow Affecting the Solids Circulation Rate in Spouted Beds with a Draft-Tube

Abstract: In a spouted bed, the gas flow rates cannot be changed independently in either the spout or the annulus. In this study, an experimental spouted bed equipped with a draft-tube was made in such a way that each of the gas flow rates can be changed independently. The effect of the gas flow rate in the spout or in the annulus on the circulation rate of solids was examined for the three types of spouted bed. The relation between the solids circulation rate and the average gas velocity in the annulus differs among these three types of spouted beds. In the spouted bed with a gas inlet nozzle, the solids circulation rate initially sharply decreased with the average gas velocity in the annulus. It was found that an eddy motion of solid particles caused this sharp decrease in the solids circulation rate. The fluid flow that caused this eddy motion in the solids was confirmed by using a two-dimensional water flow model.

Methods for Determining the Kinetic Parameters from Nonisothermal Thermogravimetry: A Comparison of Reliability

Abstract: This paper has presented some popular methods used to determine the kinetic parameters from nonisothermal thermogravimetric analysis (TGA) data. These methods include the improved Doyle–Ozawa method, and the nonlinear regression method. The above-mentioned methods along with a new method proposed by the present authors are compared with the true thermogravimetric data generated by the synthetic TG/DTG curves. This paper has shown that the proposed E2-function method has the advantages of both reliability in calculation and straightforwardness in formulation.

CO Removal from Reformed Gas by Catalytic Methanation for Polymer Electrolyte Fuel Cell Applications

Abstract: CO removal from a reformed gas by catalytic methanation on Ru/Al2O3 was studied for Polymer Electrolyte Fuel Cell (PEFC) systems. The effects of the gas composition and the reaction temperature on CO methanation activity were examined. The ratio of methanation of CO to that of CO + CO2 was also investigated. Consequently, it was found that CO could be removed from a reformed gas to below 10 ppm by controlling CO2 methanation by multi-stage CO methanation, while CO could not be reduced to below 10 ppm by single-stage CO methanation due to the presence of CO2.

Photocatalytic Degradation of Methylene Blue with Metal-Doped Mesoporous Titania under Irradiation of White Light

Abstract: Metal-doped mesoporous titania was obtained by aging a mixed solution of metal salt, polyacrylic acid (PAA) as a template and titania sol, which had been prepared by disolving titanium tetraisopropoxide (TTIP) in hydrochloric acid solution, at 333 K for 24 hours. All the metal-doped mesoporous titania were prepared from the gel solution and the crystal structure was anatase. The diffuse reflectance spectra of the metal-doped titania powder show to absorb the visible light. The metal-doped mesoporous titania powder was dispersed in an aqueous methylene blue (MB) solution and the adsorption and photodegradation of MB were characterized. The MB concentration was decreased to one-twentieth the initial concentration (48 μm) after about 15 minutes with W-doped mesoporous titania under irradiation of white light. The rapid decrease at the initial stage was caused by the adsorption, and after about 30 min products of the photocatalytic degradation of MB were observed. However, for the Fe- and Cu-doped mesoporous titania adsorbed MB in the initial stage, but the photocatalytic degradation of MB almost did not proceed.

An Analysis of Temperature Distributions in Microwave Heating of Foods with Non-Uniform Dielectric Properties

Abstract: Using flat cylindrical samples having non-uniform dielectric properties, we studied the heat transfer in food products when only the side surfaces of the samples were irradiated with microwaves. The temperature distributions in the food were measured by means of an infrared thermometer in two-dimensional form. Additionally, a transient two-dimensional heat conduction equation was induced and the temperature distributions in the food were determined using a numerical calculation. When the experimental results were compared with the results of the numerical calculations, their tendency of temperature distribution closely agreed, and it was confirmed that the mathematical model is useful in predicting the temperature distributions of food with non-uniform dielectric properties during microwave heating.

Preparation of Thermosensitive Microgel Adsorbent for Quick Adsorption of Heavy Metal Ions by a Temperature Change

Abstract: A thermosensitive microgel adsorbent, which adsorbs and desorbs a specific heavy metal ion by the temperature swing, was developed. The microgels was prepared by the emulsion polymerization using anionic polymerizable surfactant. N-Isopropylacrylamide (NIPA) and N-(4-vinyl)benzyl ethylenediamine were used as the primary monomer and the chelating monomer, respectively. In the preparation, the molecular imprinting technique using Cu(II) ions as a target heavy metal ion was adopted. The thermosensitive microgel adsorbents were dispersed stably even if the temperature of the suspension exceeded the transition temperature of poly(NIPA), and Cu(II) ions were adsorbed quickly in response to the temperature change.

Rapid Micromixing Based on Multilayer Laminar Flows

Abstract: The mixing efficiency of a simple, 32-layered micromixer was evaluated. Two liquids are each divided into 16 streams, and converged into 32 laminar flows by merging five times transversely, in turn. Miscible fluids can be mixed rapidly; and, 31 stable interfaces of fluid layers can be produced for immiscible fluids. This process is expected to increase the scope of high-speed chemical reactions and material syntheses. The micromixer used in this study was fabricated using PMMA plates which are easily processed. Mixing efficiency was evaluated by confocal fluorescence microscopy and computational fluid dynamics simulation. The results indicate that about 90% mixing was achieved within 1 s after the streams had been merged at a flow rate of 150 μl/min.

Simultaneous Measurement of 3-Dimensional Shape and Behavior of Single Bubble in Liquid Using Laser Sensors

Abstract: A novel sensing system of bubble shape, surface area, volume and rising velocity using three coupled laser sensors was developed. To confirm the reliability of the system, the bubble shape was simultaneously measured using both a high-speed video camera and this system for an identical rising single bubble. The bubble's outline analyzed using the laser scanning system corresponded well with that analyzed by the video image analysis. The measured rising velocities of bubbles agreed well over a wide range of liquid viscosity with the data of Grace (1973), and Bhaga and Weber (1981). Moreover, the measured surface area of a bubble agreed well enough with the estimation of Tadaki and Maeda (1961) under their experimental condition. With this system, not only rising velocity of a single bubble but also its three-dimensional shape and surface area could he more precisely and quickly measured in real-time.

Templated synthesis of silica hollow particles by using spray pyrolysis

Abstract: It is commonly accepted that one hollow particle is formed from one droplet in conventional spray pyrolysis or drying. Therefore, the particles size distribution is closely related to the droplet size distribution. In this report, however, a new aerosol process was proposed, in which multiple hollow particles were produced from one liquid droplet with the aid of salt and polystyrene (PS) bead. In this process, the particles size and size distribution were determined by the PS beads, not by the droplets. Silica hollow particles of 160 nm in diameter and 10 nm in shell thickness were prepared after washing off the salt with water. Geometric mean dispersion of hollow particles were 1.02, whereas the geometric mean deviation of droplets was 1.3. The role of salt was to keep nano-size hollow particles desegregated while the PS template beads were burnt off at 500°C.

Supercritical Reduction of Lauric Acid in Palm Kernel Oil (PKO) to Produce Cocoa Butter Equivalent (CBE) Fat

Abstract: The extraction of dehulled ground palm kernel using supercritical carbon dioxide (SC-CO 2 ) as a solvent at a temperature of 40°C and pressures range from 34.5 to 48.3 MPa was studied. At 48.3 MPa and 40°C the solubility of oil was about 21.1 g/100 g carbon dioxide, however maintaining constant temperature of 40°C the solubility of oil increased with pressure. The fatty acid composition of oil extracted varied with fraction time. The first fraction had 52.2 percent lauric acid content. The lauric acid content decreased to 34.3 percent in the third fraction with an increase to more than 40 percent fatty acid with 16 carbons or more. The breakdown was 0.1 percent palmitic acid (C16), 8.9 percent stearic acid (C18:0), 20 percent oleic acid (C18:1) and 4 percent linoleic acid (C18:2). Blending of palm oil (PO), palm kernel oil (PKO), stearic acid (C18:0) and oleic acid (C18:1) at different ratios were carried out to obtain blends as cocoa butter replacers (CBR) fat. The lauric and myristic acids were reduced to 9.03 and 4.44 percent in the CBE blend, although there are no lauric and a trace of myristic acid in CB. The percentages of other fatty acids in CBE were found to correlate well to the CB except C18:0 which was only 16.15 percent. The slip melting point (SMP) increased with the increase in C18:0. The value of SMP was found to be 36.1°C for the CBE blend whereas for the CB it is 35°C. The iodine value for the CBE blend was found 38.3 where as for CB it is 36. The solid fat content (SFC) of CBE at 20, 35 and 37.5°C was found to be 59.3, 8.5 and 0 percent, respectively. Whereas, the SFC values of CB are 72, 11 and 0 percent, respectively. Although the percent of the C18:0 in the CBE was lower than the commercial CB but it did not affect to the SMP and SFC.

The Preparation and Characterization of Activated Carbon from Coffee Residue

Abstract: Coffee residues from instant coffee plants were used to produce mesoporous activated carbon. A series of carbonization and activation conditions were examined to elucidate the effect of each condition. The specific surface area, mesopore and total pore volumes were evaluated by nitrogen adsorption at 77 K, and the surface chemistry was characterized by FTIR. The activated carbon derived in the conditions of a ZnCl2/coffee weight ratio of 3, an activation temperature of 600°C and a CO2 activation time of 4 h (R30T600H4) yielded a surface area of 900 m2/g, a total pore volume of 1.01 cm3/g with a mesopore content of 92%. The FTIR results demonstrated that the C–H group was the main functional group on the surface of coffee-derived activated carbon. The adsorptive capacities of R30T600H4 compared with a commercial activated carbon CAL for phenol, methylene blue and erythrosine red. We found that for small molecules such as phenol and methylene blue the adsorption capacity of R30T600H4 was lower than that of CAL, whereas, for larger molecules such as erythrosine red R30T600H4 was higher. The mesoporous structure and the surface chemistry of coffee-derived activated carbon associated in the adsorption were discussed.

DNA Extraction by Cationic Reverse Micelles

Abstract: Deoxyribonucleotide (DNA) was successfully extracted in a few hours by reverse micelles, which were formed and functionalized by a cationic quaternary ammonium surfactant in isooctane. Several parameters which affect the DNA transfer from an aqueous phase to a reverse micellar phase, such as the natures of a surfactant and a solvent, salt concentration in a feed solution, and hydrophobicity of micelles, were investigated. The use of a cationic surfactant was found to yield a high transfer rate of DNA into reverse micelles. We have attributed the DNA transfer to the electrostatic interaction between the cationic surfactant and the negatively charged DNA. We found that the higher the hydrophobicity of a surfactant used to form micelles, the better the DNA transfer efficiency in the forward extraction. Preferential extraction of DNA was achieved by using twin long-alkyl chains of cationic surfactants. However, pH in the aqueous feed solution did not affect the extraction performance of reverse micelles. On the other hand, alcohol, as a co-solvent plays an important role in the back extraction of DNAs. Complete back-extraction of DNAs was achieved without any conformational change by adding an appropriate alcohol to the reverse micellar phase.

Preparation of Platinum Catalysts Supported on Anodized Aluminum for VOC Catalytic Combustion: The Effect of Sintering

Abstract: It was found that in a volatile organic compound (VOC) catalytic combustion reaction, the dispersion of the platinum catalyst that was supported on an anodized aluminum plate by the electrolysis supporting method, decreased with the reaction time. The sintering of the catalysts was explored by the respective catalytic combustion of benzene, toluene, and ethylbenzene. The dispersions of platinum varied with reaction atmospheres during the reaction. The results of activity tests showed that catalytic activity was promoted with sintering of platinum particles. From the analysis of temperature-programmed desorption (TPD), the surface characteristics of catalysts were studied. It was found that the amount of chemisorbed aromatic hydrocarbons increased along with the sintering of platinum particles. This was applied to elucidate the activating effect of sintering.