山本 拓司

Bicellar mixtures containing diacetylene molecules, such as diynoic acids, can be used as parent materials for functional membranes. A bicellar mixture consisting of a diynoic acid-10,12-tricosadiynoic acid (TCDA)-, a phospholipid-1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-, and a detergent-3-[(3-cholamidopropyl) dimethylammonio]-2-hydroxypropanesulfonate (CHAPSO)-was evaluated for its morphology and packing of TCDA molecules in its bicellar mixture. A TCDA/DMPC vesicle was prepared at different molar ratios, TCDA/DMPC = 2/8, 5/5, and 8/2; a TCDA/DMPC/CHAPSO bicellar mixture was prepared by mixing a CHAPSO solution with a TCDA/DMPC vesicle solution as a detergent at different composition ratios, x TCDA/DMPC = [TCDA/DMPC]/([TCDA/DMPC]+[CHAPSO]), of 1.0, 0.70, 0.50, and 0.30. A DMPC molecule formed a bilayer membrane structure and was used to suppress its precipitation. The packing density of the TCDA/DMPC/CHAPSO bicellar mixtures was increased by mixing a CHAPSO molecule in x TCDA/DMPC = 1.0 to 0.70 or 0.50. A TEM image of a TCDA/DMPC/CHAPSO bicellar mixture showed many discoidal assemblies at x TCDA/DMPC = 0.5 of TCDA/DMPC = 5/5. Polymerization of the TCDA molecules in the bicellar mixture by UV light suggested an ordered arrangement of TCDA. Polymerization at x TCDA/DMPC = 0.70 and 0.50 correlated with improved packing density.

Continuous crystallization via indirect cooling of potassium aluminum sulfate dodecahydrate (KAl(SO4)(2)center dot 12H(2)O) was carried out using a draft tube-type crystallizer with a circulation flow path. The crystallizer was equipped with a newly designed system to monitor the degree of supersaturation in the circulation channel. The average degree of supercooling and growth rate were measured. The crystal growth rates calculated by the population balance model and the supersaturation monitor were different but close. The average supersaturation calculated from the supercooling degree and the solubility data in the literature was 0.19 g per 100 g H2O. This system is also expected to be applied to industrial crystallization where impurities are present.

To understand the inclusion of mother liquor in crystals at different sizes, the continuous crystallization of potassium sulfate was investigated. A bench-scale crystallizer of the draft-tube type was employed for both batch cooling and continuous crystallizations. A standard solution of potassium sulfate was employed as the saturated solution at 323 K. The batch cooling crystallization was first performed at 283 K at a rate of 5 K/h, after which the continuous crystallization was performed at 283 K at two different residence times. The crystal size distribution (CSD) of potassium sulfate crystals and the inclusion ratio of mother liquor in the crystals at different sizes were measured. The average size of the crystals was approximately 400-500 mu m, and the inclusion ratio was less than 1% for all sizes; however, the small and large crystals contained a considerable amount of mother liquor, and the specific crystals that exhibited the lowest inclusion ratios were investigated. Moreover, an impurity distribution model for the suspension crystals was proposed based on coreaggregation and shell-growth processes.

A new method for determining the liquidus and solidus pressures of mixtures of C18's unsaturated fatty acids at constant temperatures was proposed, and three binary isothermal SLE data under high-pressure were systematically measured in this study. The liquidus and solidus temperatures of oleic acid, linoleic acid and alpha-linolenic acid commonly rise above their normal melting temperatures when pressure is increased. This new high-pressure experimental system can closely track pressure in real time during pressure swinging changes, making it simple to measure liquidus and solidus pressures using this dynamic measurement method due to fast responsiveness of pressure. In this study, the liquidus pressures of pure oleic acid, linoleic acid, alpha-linolenic acid and three binary mixtures consisted of oleic acid, linoleic acid alpha-linolenic acid at constant temperature were determined. The isothermal SLE were first correlated based on a simple thermodynamic model. (C) 2021 Elsevier Ltd.

Bicelles are extensively used as the parent assemblies of functional membrane materials. This study characterizes membrane fluidity in fatty acid/detergent bicelles containing carboxyl boron-dipyrromethene (BODIPY C12) and pyrromethene as fluorescent probe molecules. The anisotropy value of BODIPY C12 and pyrromethene in the phospholipid vesicles depended on the phase state of the vesicles. The anisotropy of the fluorescent probe molecules in bicelles of oleic acid/3-[(3-cholamidopropyl) dimethylammonio]-2-hydroxypropane sulfonate (OA/CHAPSO) was then evaluated. The OA/CHAPSO bicelles were prepared by mixing CHAPSO detergent solution with OA vesicles at different molar ratios, XOA (= [OA]/([OA]+[CHAPSO])). The anisotropies of the probes in the OA/CHAPSO bicelles increased with decreasing XOA. BODIPY C12 in the range 0.30 ≤ XOA ≤ 0.70 exhibited a distinctly larger anisotropy than pyrromethene. This result agreed with the increase in packing density associated with the adsorption of CHAPSO molecules on the OA bilayer membrane in the OA/CHAPSO bicelle, revealing that the anisotropy of BODIPY C12 molecule enables membrane-fluidity evaluation in OA/CHAPSO bicelles.

Oleic acid/3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxypropane sulfonate (OA/CHAPSO) bicellar mixtures are potential functional membrane materials. The lipid transfer during the formation of these bicellar mixtures was evaluated. The OA/CHAPSO bicellar mixture was prepared by mixing a solution of OA vesicles as a source of bilayer membranes with a solution of CHAPSO as a detergent at different composition ratios, xOA (= [OA] / ([OA] + [CHAPSO])). The lipid transfer was evaluated based on the leakage of fluorescent probe molecules, i.e., carboxyl boron-dipyrromethene (BODIPY C12), from the OA bilayer membranes. Mixing the CHAPSO solution with the OA vesicle eliminated the self-quenching of BODIPY C12 because of the leakage of BODIPY C12 molecules. The apparent rate constant of the leakage increased with decrease in xOA to 0.60. However, at xOA ≤ 0.60, the apparent rate constants barely changed. The correlation between the leakage of the BODIPY C12 molecules and the transfer of OA molecules enables the evaluation of the lipid transfer during the OA/CHAPSO bicellar mixture formation through the observation of the self-quenching of BODIPY C12.

To improve energy production cost, it is necessary to operate bioreactors at a deeper depth to increase per unit area production; however, self-shading could be an inhibiting factor. Therefore, it is important to employ a variety of agitators so that microalgae in deep regions can be agitated, allowing sufficient aeration. We aimed to evaluate the effectiveness of a self-sufficient aerator in an open pond cultivation system for a microalga. Three experimental cases with different agitation velocities (high: Casehigh; low: Caselow; no agitation: Casezero) were evaluated. In Caselow, cells grew fastest in the early stage of cultivation due to reduced mechanical shear stress. However, the increased turbidity after 150 h reduced the cell density and increased chlorophyll a content, which could be attributed to low light intensity. The maximum TAG content was achieved in Casehigh. The findings suggest that strong agitation using an aerator can promote TAG accumulation.

Three different salt crystals (K2SO4, KCl, and Na2SO4·10H2O) were produced via batch cooling and continuous crystallization using a bench-scale crystallization device, in order to elucidate the mechanism of inclusion of the mother liquor as a function of crystal size. The inclusion ratio of the mother liquor was higher at small sizes and decreased with crystal growth. All results were represented by the previously proposed model of core-aggregation and shell-growth processes for the three different salt crystals. Crystals with small Vickers hardness aggregated with each other, and the inclusion ratio of the mother liquor of aggregated grown crystals was high for all three salt crystals tested herein.

The separation of the binary unsaturated fatty acids C18:1 + C18:2 system was examined by high-pressure crystallization at 298 K (25 °C). The binary fatty acid mixture containing 0.8 mol fraction of C18:1 was packed in the glass cell with a free piston, and then pressurized by an aqueous ethanol solution around the glass cell up to 200 MPa. The complete solid mixture was obtained after cooling at 253 K (- 20 °C) as a depressurized binary solid. The solid was divided into four parts, and the composition of C18:1 was analyzed at each part of the solid using a refractometer, which revealed there was a composition distribution throughout the solid with C18:1 crystallized one-directionally from the top to the bottom of the cell. High-pressure crystallization could be effective for the separation of binary fatty acids.

We evaluated the effect of dilution on both the size and packing density of aggregates prepared from a fatty acid (oleic acid, OA)/detergent (3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxypropane sulfonate (CHAPSO)) bicelle as a parent for functional membrane materials. The sizes of the aggregates formed at different molar ratios, X_OA(= [OA]/([OA]+[CHAPSO])), of 0.3 and 0.7 and their parent bicelles were measured by dynamic light scattering and transmission electron microscopy; their packing density was evaluated by deconvolution of the fluorescence spectrum, where Laurdan molecules were used as a probe. The experimental results showed that the bicelles formed aggregates upon dilution because of the hydration of CHAPSO. The packing density of the nano-ordered aggregate formed at X_OA = 0.3 was much greater than that of the aggregate formed at X_OA = 0.7, implying the formation of an ordered aggregate under the condition of X_OA = 0.3

A bicelle, which is a bilayer molecular assembly, can be prepared by fluidizing a vesicle in the presence of a detergent. We investigated the effect of two different detergents, 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxypropane sulfonate (CHAPSO) and Triton X-100 (TX), on the formation of a bicelle from a vesicle containing oleic acid (OA) and the detergent molecules. The fluidization effect of the detergent was evaluated using the membrane packing density, which we measured using the fluorescent probe method with Laurdan, in conjunction with transmission electron microscopy to examine the morphology of the prepared bilayer molecular assemblies. As a result, it was discovered that the OA/CHAPSO system could form a heterogeneous phase with the highest packing density, implying that CHAPSO was the better detergent for a bicelle preparation, whereas the OA/TX system formed a disordered phase with the lowest packing density.

A bicelle is a non-spherical, bilayer molecular assembly that has potential application as a functional membrane material. In this study, we examined the effect of molar ratio in preparing bilayer molecular assemblies from oleic acid (OA) and a detergent (CHAPSO) by evaluating the size and the membrane packing of the prepared molecular assemblies. As a result of the measurement by dynamic light scattering, the size of the solubilized molecular assemblies could be controlled in the range of 22.5–135 nm by varying the molar ratio of OA, X (=[OA]/([OA]+[CHAPSO])), in the range of 0.3–0.7. The fluorescent probe method employing Laurdan revealed that the membrane packing of the solubilized assemblies prepared from OA and CHAPSO was heterogeneous, and that a bilayer structure containing bicelles was probably formed. Moreover, it was found that addition of Na as a counterion improved the dispersion stability of the bilayer molecular assembly prepared. OA +

In this study, batch crystallization via indirect cooling and continuous crystallization via direct and indirect cooling of phosphoric acid hemihydrate (H3PO4.1/2H2O) from the mixed acid solution of phosphoric acid and acetic acid are performed. In batch crystallization, needle-shaped crystals are obtained, and the impurity concentration of acetic acid in the crystals is 4.2 wt%. Primary nucleation occurred under a high degree of supersaturation, and the metastable zone width for secondary nuclei is narrow. In contrast, in continuous crystallization via indirect cooling, scaly crystals are obtained, and the acetic acid impurity concentration therein is 2.0 wt%. Additionally, continuous crystallization via direct contact cooling is performed, the crystal shape and impurity concentration under direct cooling are similar to those under indirect cooling, suggesting the possibility to downsize the apparatus. Through utilization of the equipment and approach elaborated herein, the correlation between the operating conditions and crystal quality can be assessed.

In electroless nickel-phosphorus plating (ENPP), growth of the plated layer under high pressure was found to be faster than under ambient pressure. To quantitatively elucidate the effect of high pressure on the mechanism of the ENPP reaction, we propose a kinetic model that takes into account both mass transfer and reaction of the chemical species present in the plating solution. We solved the mass balance equations between the chemical species to calculate the transient changes in the thickness of the plated layer as well as the concentrations of the chemical species in the plating solution. By fitting the calculated results to the experimentally acquired results based on the nonlinear least square method, we determined such parameters as the film mass transfer coefficient, the adsorption constants, and the reaction rate constants of the chemical species in the model. As a result, we found that the film mass transfer coefficient under high pressure was greater than that under ambient pressure and revealed the dependence of the coefficient on pressure. The transient changes in the concentrations of the chemical species in the plating solution that we calculated based on the kinetic model employing our estimated parameters closely modeled the experimental results with the determination coefficients being mostly over 99%.

We investigate the vapor bubble stability in liquid argon and water using a molecular dynamics simulation. The Lennard-Jones interparticle interaction potential is used to simulate the interaction forces between molecules. The Stillinger' s cluster criterion is employed to classify the vapor molecules evaporated from the bulk liquid. Using this criterion, the vapor molecules are determined to have no neighboring molecules within a 1.23 to 1.32σ radius, where σ is the interaction radius in the L-J potential. The pressure of vapor and liquid phase can be calculated from the virial equation of sate. The stability of bubble is disscussed applying the Young-Laplace equation. The spherical bubble shape is maintained, when the liquid pressure takes the negative value. The thickness of vapor-liquid interface and the number of molecules across vapor-liquid interface are not proportional to the size of bubbles.

We examined the degradation of aqueous phenol by ozonation in an aerated mixing vessel, which was combined with a fixed-bed reactor packed with high-silica zeolite (HSZ) pellets. Ozone-containing oxygen gas was introduced as fine bubbles through a sparger placed in the aerated mixing vessel, whereas the aqueous phenol solution was circulated between the vessel and the reactor. Measurements of transient changes in the concentration of both phenol and total organic carbon in the treated solution revealed that the degradation of phenol or total organic carbon by ozonation was enhanced by the presence of HSZ because both phenol and ozone could adsorb on the hydrophobic micropores. As a result of quantitative analysis of the treated solution, it was found that catechol, hydroquinone, humic acid, and maleic acid were the possible reaction intermediates during ozonation of aqueous phenol employing HSZ.

In this study, we investigate the vapor bubble stability in liquid argon using a molecular dynamics simulation. The Lennard-Jones (L-J) interparticle interaction potential is used to simulate the interaction forces between argon molecules. The discrimination method based on Stillinger's cluster criterion is employed to classify the vapor molecules evaporated from the bulk liquid. In this criterion, the vapor molecules are determined to have no neighboring molecules within a 1.23 to 1320 sigma radius, where sigma is the interaction radius in the L-J potential. It is found that the spherical bubble shape is maintained and the Young-Laplace equation applies mainly as a result of the large negative pressure of the liquid. The 10-90 thickness of the vapor-liquid interface was approximately 30 to 90% of the bubble radius in the present simulation. A certain frequency of condensation and evaporation was maintained in the smaller bubble case, which is not proportional to the decrease in bubble surface area. (C) 2017 Elsevier B.V. All rights reserved.

Yeast cells were immobilized in freeze-dried poly(vinyl alcohol) (PVA) foam, and the subsequent fermentation of glucose was studied. The immobilized yeast was produced by freeze-drying a PVA solution containing dispersed yeast cells, yielding a porous foam. The prepared specimens were rigid enough to be used repeatedly in aqueous solutions for more than one week. The fermentation performance of the immobilized yeast was found to be significantly higher than that of the crude (non-immobilized) yeast. The immobilized yeast produced approximately 1.5 times more ethanol than the crude yeast. The freeze-dried PVA also appeared to protect the yeast cells against the reaction inhibition effects of ethanol. Also, the PVA foam had a considerable a affinity for the yeast cells, whereas it had no significant affinity for ethanol. The kinetic constants obtained from the experimental reaction runs suggested that the improvement in the fermentation of the immobilized systems can be explained by the increase in the dissociation constant values in the Michaelis-Menten kinetic model, and that there is an optimal quantity of immobilized yeast that yields the best ethanol tolerance for this technique.

To study solute distribution at the solid-liquid (S-L) interface during melt crystallization, we examined the applicability of the interfacial solute distribution factor proposed based on a kinetic model involving both mass and heat balances at the interface. The factor derived from the model was compared with the experimental results obtained by employing a binary melt with the different species and concentrations of fatty acids as biodiesel related mixtures. As a result, we were able to reveal the empirical relation between the purity of the crystal and the solidification conditions of the melt. Based on the model, we also numerically calculated the transient changes in the interfacial solute distribution factor as well as the temperature of the S-L interface in the solidification process of the melt. The minimization of the factor was confirmed when the melt was supercooled at the S-L interface after starting solidification. (C) 2015 Elsevier Ltd. All rights reserved.

A quartz crystal microbalance (QCM) was utilized to measure the water content in ethanol. For the improvement of measurement sensitivity, the QCM was modified by applying zeolite particles on the surface with poly(methyl methacrylate) (PMMA) binder. The measurement performance was examined with ethanol of 1% to 5% water content in circulation. The experimental results showed that the frequency drop of the QCM was related with the water content though there was some deviation. The sensitivity of the zeolite-coated QCM was sufficient to be implemented in water content determination, and a higher ratio of silicon to aluminum in the molecular structure of the zeolite gave better performance. The coated surface was inspected by microscopy to show the distribution of zeolite particles and PMMA spread.

Anti-solvent crystallization from a ternary mixture was examined by an NpT ensemble molecular dynamics simulation. The co-solvent and anti-solvent effects were represented by the Lennard-Jones interaction energy parameter, ε&lt inf&gt ij&lt /inf&gt . The homogeneous binary solution of the solute and solvent was achieved at a constant temperature and pressure. Anti-solvent crystallization was introduced by changing some co-solvent molecules to anti-solvent molecules, immediately. The configuration of solute molecules was investigated by using the radial distribution function, g(r), and the local composition, x&lt inf&gt L&lt /inf&gt . The value of ε&lt inf&gt ij&lt /inf&gt affected the configuration of the solute molecules significantly the decrease in ε&lt inf&gt ij&lt /inf&gt provided the localization and crystallization of the solute molecules. The composition of the anti-solvent molecules in the solution also affected the configuration of the solute molecules the increase in the anti-solvent composition produced the crystal structure of the solute molecules more rapidly. These qualitative results corresponded well to anti-solvent crystallization. The radial distribution function represented the crystal structure for solute molecules, and the local composition of the solute was increased from the bulk composition as the effect of the anti-solvent increased. We proposed that the time variation of the local composition of the solute represents the temporal development of the crystal structure and the time to crystallization well.

With the aim of removing hydrogen sulfide (H2S) from a gaseous phase around room temperature, we studied the performance of an iron oxyhydroxide (ferrihydrite) adsorbent by measuring a packed bed breakthrough curve (BTC) in a constant gas flow. We determined the amount of H2S adsorbed on the adsorbent by integrating BTCs measured under different experimental conditions. These conditions included the initial concentration of H2S, the superficial gas velocity and the temperature of the packed bed. Under the experimental conditions, it was found that the amount of H2S adsorbed was almost unchanged by the superficial gas velocity, whereas the adsorbed amount depended on the initial concentration of H2S and temperature. To solve the mass transfer equations in the packed bed, we developed a model considering such parameters as the kinetic constant of the sulfidation reaction, the intragranular diffusivity of H2S, and the number density of active sites on the adsorbent. By fitting the calculated BTC to the measured BTC under one of the experimental conditions, the set of parameters could be estimated. Using the same set of estimated parameters, we calculated the BTCs under the other experimental conditions. As a result we confirmed that the calculated BTC coincided with the BTC measured under a different initial H2S concentration and gas velocity. We also found that the number density of the active sites increased with increases in temperature. (C) 2014 Elsevier B.V. All rights reserved.

An in-line device for measuring the water content in ethanol was developed using a polyvinyl alcohol (PVA)-coated quartz crystal microbalance. Bio-ethanol is widely used as the replacement of gasoline, and its water content is a key component of its specifications. When the PVA-coated quartz crystal microbalance is contacted with ethanol containing a small amount of water, the water is absorbed into the PVA increasing the load on the microbalance surface to cause a frequency drop. The determination performance of the PVA-coated microbalance is examined by measuring the frequency decreases in ethanol containing 2% to 10% water while the ethanol flows through the measurement device. The measurements indicates that the higher water content is the more the frequency reduction is, though some deviation in the measurements is observed. This indicates that the frequency measurement of an unknown concentration of water in ethanol can be used to determine the water content in ethanol. The PVA coating is examined by microscopy and FTIR (Fourier transform infrared) spectroscopy.

A process simulator was developed for the synthesis of bio-propylene from bio-ethanol with a zeolite catalyst by determining the reaction mechanism and the reaction rate constants that simulate the experimental data. The reaction mechanism thus determined consisted of 28 reactions involving 16 chemical species. The values of the reaction rate constants (the frequency factors and the activated energies) were determined by use of a genetic algorithm to solve the non-linear optimization problem of minimizing the differences between the simulated values and the experimental data. As a result, the behavior of experimental data, especially for the major species such as propylene and ethylene, was well explained by the output of the simulator developed in this work. Therefore, the simulator should be useful for optimizing the design and the operation of reactor in this process. © 2013 The Society of Chemical Engineers, Japan.

Bioethanol has recently become an important resource for chemical industries. The chemical compositions of 17 different types of bioethanol were investigated with a focus on impurities that could affect catalytic performances in the downstream chemical processes. Lignocellulosic ethanol contained higher concentrations and a greater variety of organic impurities compared to sugar- or starch-derived bioethanol. Twenty-nine impurities were identified in lignocellulosic ethanol, whereas 16 impurities were in sugar- or starch-derived bioethanol. Lignocellulosic ethanol contained high concentrations of acetic acid, acetaldehyde, methanol, and furan-related compounds such as furfural. In contrast, with the exception of molasses-derived bioethanol obtained by crude distillation, the concentrations of these components were lower in sugar- or starch-derived bioethanol samples. Lignocellulosic ethanol contained dimethyl disulfide and thiazole, whereas the only organosulfur compounds found in sugar- or starch-derived bioethanol were dimethyl sulfde and dimethyl sulfoxide. These sulfur-containing impurities can cause catalyst deactivation in the bioethanol transformation processes. In lignocellulosic ethanol, more than 0.1 μg/mL of Si was detected.

The adsorption characteristics of zeolites with different framework structures and different exchanged cation species were examined with a view to using zeolites as adsorbents for the dehydration of ethanol. We measured the adsorption isotherm of water vapor on zeolites, the differential heat of the adsorption of water vapor, the liquid-phase adsorption isotherm of water in ethanol and packed bed breakthrough curves (BTC) for the adsorption of water in ethanol. As a result, we confirmed that an LTA or FAU zeolite exchanged with a monovalent cation species, such as a sodium cation or a potassium cation, showed a strong affinity to water in ethanol. We also found that the Langmuir model explained the liquid-phase adsorption of water in ethanol on the zeolite more accurately than the Freundlich model. Using the constants determined from the Langmuir isotherm, we calculated the BTC for a zeolite packed bed as regards the dehydration of ethanol. The intra-particle diffusion coefficient of water in the zeolite particles was estimated by fitting the calculated BTC to the experimental result. (C) 2011 Elsevier B.V. All rights reserved.

In the development of the ethanol-to-olefin (ETO) conversion process to produce polymer-grade propylene from cellulosic bioethanol which contained an organosulfur impurity, adsorptive desulfurization of propylene using porous iron oxide (PIO) was examined. We evaluated the performance of PIO for the adsorption of hydrogen sulfide (HS), which was changed from the organosulfur impurity in bioethanol during the ETO conversion, by the measurement of a packed-bed breakthrough curve in a gas phase under the different temperature and pressure. We confirmed that PIO was capable of removing HS selectively from the mixed gas containing propylene, because of the reactivity of PIO with HS even at low temperature. The amount of adsorbed HS on PIO was found to increase with the increase in the temperature or pressure. As a result, the concentration of HS in the desulfurized gas could be reduced lower than 10 ppb. Copyright © 2012, AIDIC Servizi S.r.l.

To synthesize polymer-grade propylene from bioethanol containing an organosulfur compound such as dimethylsulfide (DMS) or dimethylsulfoxide (DMSO), we examined the adsorptive desulfurization of propylene by employing commercial activated alumina. It was found that both DMS and DMSO were converted predominantly to hydrogen sulfide during the catalytic conversion of ethanol to propylene over HZSM-5 zeolite. The performance of the adsorbent was evaluated by measuring a packed-bed breakthrough curve for the adsorption of hydrogen sulfide in gaseous propylene. Because of the adsorptive desulfurization, the concentration of hydrogen sulfide in propylene could be reduced to less than 10 ppb.

In the development of the ethanol-to-olefin (ETO) conversion process to produce polymer-grade propylene from cellulosic bioethanol which contained an organosulfur impurity, adsorptive desulfurization of propylene using porous iron oxide (PIO) was examined. We evaluated the performance of PIO for the adsorption of hydrogen sulfide (HS), which was changed from the organosulfur impurity in bioethanol during the ETO conversion, by the measurement of a packed-bed breakthrough curve in a gas phase under the different temperature and pressure. We confirmed that PIO was capable of removing HS selectively from the mixed gas containing propylene, because of the reactivity of PIO with HS even at low temperature. The amount of adsorbed HS on PIO was found to increase with the increase in the temperature or pressure. As a result, the concentration of HS in the desulfurized gas could be reduced lower than 10 ppb.

Recently, an increase in the use of boron compounds has led to an increase in boron emissions, and concern has grown regarding its detrimental effects on the human body. An adsorbent that adsorbs boron selectively has been developed as a countermeasure. Although certain commercially available boron selective adsorbents can be used to remove boron from aqueous solutions by utilizing the strong affinity between boron and hydroxyl groups, the adsorption capacity appears to be insufficient. So, we adopted polyvinyl alcohol (PVA), which contains many hydroxyl groups, as a model adsorbent. We investigated the boron adsorption characteristics of PVA, and then studied the relationship between the number of adsorption sites and actual adsorption amounts. We assessed the adsorption result by using adsorption site availability (ASA) as an indicator of the ratio of effectively functioning hydroxyl groups from the many hydroxyl groups in PVA. ASA was expressed as a percentage of the experimental equilibrium adsorbed amount in relation to the theoretical equilibrium adsorbed amount. We also compared the adsorption isotherms and ASA obtained with PVA, commercially available N-methylglucamine-type resin (CRB03 and CRB05) and the adsorbent we synthesized from polyallylamine (PAA) and glucose (PAA-Glu). Although PVA has many hydroxyl groups in a molecule, ASA analysis revealed that only 6% of the hydroxyl groups in PVA was used for boron adsorption. On the other hand, CRBs and PAA-Glu exhibited higher ASA values (about 15% and 35% respectively) and adsorption amounts, suggesting that the sterically congested adsorbent structure had a great influence on boron adsorption and ASA.

A macroporous carbon foam (MCF) possessing three-dimensionally interconnected porous structure, that was composed of macropores, mesopores and micropores, could be synthesized by the oil-in-water (o/w) emulsion templating method using ultrasound. For the preparation of the o/w emulsion as a template of the macropores formed in the MCF, a resorcinol-formaldehyde (RF) solution and cyclohexane were used as an aqueous phase and an oil phase, respectively. We examined the effects of the viscosity of the RF solution, the mass ratio of cyclohexane with the RF solution as well as the concentration of a hydrophilic surfactant (Tween80) contained in the RF solution on the size distribution of the macropores. Consequently, the suitable viscosity of the RF solution to obtain a MCF with a narrow size distribution of the macropores was determined. It was revealed that the size of the macropores increased with the increase in the mass ratio of cyclohexane with the RF solution or with the decrease in the concentration of Tween80. It was possible to increase the porosity of the prepared MCF larger than 90% using a concentrated o/w emulsion as the template of the macropores.

We studied adsorption characteristics of a series of LTA zeolite as an adsorbent for desulfurization of propylene, that was produced from bioethanol by ethanol-to-olefin (ETO) conversion. A breakthrough curve (BTC) for adsorption of methanethiol, as one of the sulfur impurities of propylene produced from bioethanol, in the presence of propylene was measured using a fixed-bed column packed with the LTA zeolite. The BTC revealed that the effect of the competitive adsorption of propylene on the LTA zeolite strongly depended on a cation species exchanged in the micropores of the zeolite. Among the cation species examined in this study, bivalent cation of zinc (Zn(2+)) was proved to be the most effective one to increase the amount of methanethiol adsorbed on the LTA zeolite under the presence of propylene. The specific interaction of methanethiol with the LTA zeolite exchanged with Zn(2+) was confirmed by the measurement of a temperature-programmed desorption (TPD) spectrum of methanethiol.

A macroporous carbon foam (MCF) possessing numerous interconnected macropores (pore diameter >50 nm) was synthesized using an oil-in-water (O/W) emulsion, which was prepared by direct irradiation with ultrasound, as a template to form the macropores. In this method, a resorcinol-formaldehyde (RF) solution, cyclohexane and a nonionic surfactant were used as an aqueous phase, an oil phase and an emulsifier, respectively. To synthesize macroporous materials based on the emulsion templating method, ultrasonic emulsification was confirmed to be a process intensification method from the viewpoint of the capability of preparing an O/W emulsion with a smaller droplet size than by mechanical mixing. As a result, it was possible to obtain a MCF with small macropore diameter ranging from submicron to several microns. The sizes of both macropores and mesopores (2 nm<pore diameter<50 nm) formed in the skeletal structure of the MCF could be changed by varying the concentration of sodium carbonate used as the catalyst for the sol-gel polycondensation of the RF solution.

Global reaction enhancement (GRE) by periodic operation was investigated via numerical simulation in a chemical process for converting methanol to light olefins. The periodic operation used was a sinusoidal variation in the reactor wall temperature along its axis. Appropriate wall temperature modulation was found to increase the ethylene and propylene yields by up to ca. 3%, compared with that obtained with the corresponding optimum uniform wall temperature. The result suggested that GRE could be achieved, and periodic operations or non-uniform temperature setting were effective methods to accomplish process intensification.