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A modified gas-translation (GT) model was applied for the theoretical analysis of gas permeation through microporous organosilica membranes derived from bis(triethoxysilyl)ethane (BTESE) via a sol–gel method using different water/alkoxide molar ratios. The pore sizes of BTESE-derived membranes were quantitatively determined by normalized Knudsen-based permeance analysis, which was based on a modified-GT model, using experimentally obtained permeances of He, H2, N2, C3H8, and SF6. The pore sizes of BTESE-derived membranes were successfully controlled from 0.65 to 0.46 nm by increasing the H2O/BTESE ratio from 6 to 240. Furthermore, theoretical correlations of all possible pairs of permeance ratios were calculated based on the modified-GT model. The experimental data were in good agreement with the theoretical correlation curves, indicating that the modified-GT model can clearly explain gas permeation mechanisms through microporous membranes, and, thus, can be used to predict the gas permeation properties for these membranes. © 2014 American Institute of Chemical Engineers AIChE J 60: 4199–4210, 2014

The sol–gel method was applied to fabrication of amorphous silica membranes, which have different silica network sizes caused by control of the calcination temperatures. The effects of fabrication temperature on small gas (He, H2, Ne, NH3, CO2, N2, and CH4) permeation properties through silica membranes were evaluated quantitatively using modified gas translation (GT) model. A silica membrane fired at 550 °C showed He and H2 permeances of 8.6 × 10–7 and 5.5 × 10–7 mol m–2 s–1 Pa–1 with He/CH4 and H2/CH4 permeance ratios of 2350 and 1500 at 500 °C, respectively. The thermal stability was dramatically improved by the fabrication of deposited silica glass intermediate layer because N2 permeance showed slight change, and the membrane showed a H2/N2 permeance ratio above 100 even heat-treated at 750 °C. The estimated silica network size decreased from 0.385 to 0.347 nm when a membrane was fabricated at 750 °C, which was consistent with the trend in activation energy of gas permeation. H2 molecules were more pe...

Using 1,2-bis(triethoxysilyl)ethane (BTESE) as a single precursor, a uniform, defect-free and perm-selective organosilica layer was successfully deposited onto porous polysulfone ultrafiltration (PSF-UF) supports via a simple sol–gel spin-coating and thermal-treatment process. The layered hybrid membranes, where BTESE-derived SiO2 is deposited on polymer supports, were applied to the vapor permeation dehydration of isopropanol–water (90/10 wt%) solutions at 105 °C, and demonstrated a water flux of 1.6 kg/m2 h and a separation factor of 315 with no selectivity for a PSF-UF support. Long-term stability testing of vapor permeation also confirmed the excellent stability of these BTESE/PSF-UF layered hybrid membranes. Moreover, compared with porous PSF-UF supports, this layered hybrid membrane also showed improved gas separation performance and a moderate (≈10) separation factor for H2/N2.

Sol–gel derived microporous amorphous TiO 2 –ZrO 2 –organic composite membranes were prepared by two different types of chelating ligands, diethanolamine (DEA) and isoeugenol (2-methoxy-4-propenylphenol, ISOH) as reaction inhibitors for hydrolysis and condensation of Ti- and Zr-alkoxide. The structural properties of the composite gels were characterized via a thermogravimetric study (TG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and N 2 adsorption analysis; and the optimized calcination atmosphere and temperature conditions for a microporous membrane were examined. A crack-free thin (50 nm) TiO 2 –ZrO 2 –organic layer for gas separation was formed on a SiO 2 –ZrO 2 intermediate layer (150 nm) supported on a macroporous α-Al 2 O 3 substrate as an asymmetric membrane. Compared with DEA, more of the ISOH and its remnants effectively remained after calcination, which promoted higher permeance and selectivity as a microporous gas separation membrane by forming bimodal microporous structures that narrowed the original TiO 2 –ZrO 2 pores. A TiO 2 –ZrO 2 membrane with ISOH calcined at 350 °C under a N 2 atmosphere showed He and CO 2 permeances of 1.0×10 −6 and 2.0×10 −7 mol m −2 s −1 Pa −1 , respectively, at 200 °C. The CO 2 /N 2 permeance ratio was 6.4 at 200 °C and 46 at 35 °C.

High-performance organic–inorganic hybrid silica membranes were developed for use in membrane reactors for methylcyclohexane (MCH) dehydrogenation to toluene (TOL). The membranes were prepared via sol–gel processing using bis(triethoxysilyl)ethane (BTESE). In particular, the effect of hydrolysis conditions (H2O/BTESE molar ratio) on membrane performance was extensively investigated. Characterization based on TG-MASS, FTIR, N2 adsorption and positron annihilation lifetime (PAL) measurements of BTESE-derived silica gels revealed that the ethoxides of BTESE were almost completely hydrolyzed and the silica networks became dense by increasing the H2O/BTESE molar ratio from 6 to 240. BTESE-derived silica membranes showed a hydrogen permeance that was higher than 1×10−6 mol/(m2 s Pa). H2/TOL selectivity increased from 100 to 10,000 by increasing the H2O/BTESE molar ratio from 6 to 240, while keeping a hydrogen permeance of more than 1×10−6 mol/(m2 s Pa). In MCH dehydrogenation, a BTESE-derived silica membrane reactor with a Pt/γ-Al2O3/α-Al2O3 bimodal catalytic layer achieved MCH conversion of 75% that was higher than the equilibrium conversion of 60%, and a hydrogen purity in the permeate stream of more than 99.9% at 230 °C.

Hybrid organosilica membranes have become attractive for industrial applications because of high performance and long-term stability. This work investigated the influence of water vapor on CO2 gas permeation through the hybrid membranes. Two types of organoalkoxysilanes, bis(triethoxysilyl)ethane (BTESE) and bis(triethoxysilyl)octane (BTESO), were used as precursors to prepare membranes via the sol–gel method. The two membranes showed distinct properties of porosity and water affinity because of the differences in the bridging methylene numbers between the two Si atoms. Under dry conditions, the BTESE and BTESO membranes showed CO2 permeances as high as 7.66 × 10–7 and 6.63 × 10–7 mol m–2 s–1 Pa–1 with CO2/N2 selectivities of 36.1 and 12.6 at 40 °C, respectively. In the presence of water vapor, CO2 permeance was decreased for both membranes, but the effect of water vapor on CO2 permeation was slighter for BTESO membranes than it was for BTESE membranes because of more hydrophobicity and denser structures ...

To date, Ru is the most active single-metal catalyst known for ammonia decomposition, but its catalytic activity is support-dependent and structure-sensitive. Therefore, a unique support-anchored Ru nanoparticle with controllable size and morphology would be particularly important for high catalytic performance. In this work, we describe Ru nanoparticles supported by two-dimensional graphene nanosheets with a controlled nanoarchitecture that forms a novel composite catalyst that is capable of a high degree of ammonia decomposition. This high-quality Ru/graphene nanocomposite material was obtained via a cosolvent method (CS-Ru/graphene), in which ethylene glycol simultaneously acted as a solvent and a reductant, while water served only as a cosolvent. The abundant oxygen-containing functional groups of graphene oxide played extremely important roles in the growth of Ru nanoparticles on the resultant graphene nanosheets, as they promoted Ru nucleation and acted as anchor sites for the Ru nanoparticles. Moreover, the use of water as a cosolvent was an effective way to tune the Ru particle size and morphology and aid in the loading of the nanocomposite, resulting in dramatically enhanced catalytic activity in comparison with a composite prepared by using ethylene glycol as a single solvent (SS-Ru/graphene). The exceptional catalytic performance of CS-Ru/graphene was mainly ascribed to the novel graphene support that simultaneously combines a large specific surface area with excellent electronic conductivity, but also to the highly dispersive Ru nanoparticles that made up the nanocomposite with a controlled morphology and an optimal size.

Organosilica membranes for gas separation were prepared on porous substrates by means of plasma-enhanced chemical vapor deposition (PECVD) using hexamethyldisiloxane as a precursor. Before the deposition of organosilica membranes, two types of intermediate layers with different pore sizes, a TiO2 layer (dp ≈ 5 nm) and a SiO2–ZrO2 layer (1 nm), were prepared on α-alumina porous supports via a sol–gel method. The stability at high temperatures was evaluated by measuring the gas permeation characteristics before and after heat treatment. PECVD membranes deposited on a SiO2–ZrO2 intermediate layer were found to be more thermally stable than those deposited on a TiO2 intermediate layer. After the treatment at 500 °C, the membranes deposited on a SiO2–ZrO2 intermediate layer had a selectivity of ∼1040 for He against SF6 with a He permeance of 1.41 × 10−6 mol/(m2 s Pa) at 50 °C, although the organosilica membranes were prepared at room temperature. On the other hand, the membrane deposited on a TiO2 intermediate layer became non-selective after heat treatment at 400 °C. The temperature dependence of single gas permeance for the membrane deposited on a SiO2–ZrO2 intermediate layer was measured after the high-temperature stability test. The permeation of He, H2 and N2 for the 200 °C-treated membrane showed an activated diffusion, while those for the 500 °C-treated membrane followed a Knudsen permeation, suggesting that heat treatment at 500 °C formed pores that allowed the permeation of molecules that were the size of N2 (0.364 nm) and smaller. In addition, since the permeation of SF6 for the 500 °C-treated membrane showed an activated diffusion, the membrane should have a uniformed structure with a small number of pinholes.

A promising new triazine-based nitrogen-rich organosilica (TTESPT) membrane has been developed for molecular separation processes in gas (gas separation) and liquid phases (reverse osmosis (RO)). By adjusting the H2O/TTESPT molar ratio, we found a promising technique for tuning the pore network of TTESPT membranes. An increase in the H2O/TTESPT molar ratio from 60 to 240 fully hydrolyzed all the ethoxide groups in the TTESPT membrane, which reduced the size of the pores in the silica pore network. A TTESPT membrane with a high H2O/TTESPT molar ratio exhibited a high degree of selectivity for H2/SF6 (greater than 4000) at a permeation temperature of 200 °C. This membrane also demonstrated high sodium chloride (NaCl) rejection (>98.5%) with water permeability of >1 × 10−12 m3 m−2 s−1 Pa−1 under operating conditions of 1 MPa and 60 °C during a RO experiment. As the operating temperature was increased from 25 to 60 °C, the NaCl rejection was constant without displaying the characteristic flux deterioration. This showed that the membrane retained a stable hybrid network structure.

Thermally stable organosilica amorphous membranes were fabricated by in situ hydrosilylation of vinyl and hydrosilyl groups in Si precursors for the formation of a Si–C–C–Si unit, as well as the Si–O–Si unit via the conventional hydrolysis and condensation of silanol groups. Two types of SiOC membranes (VTT-type prepared by vinyltrimethoxysilane (VTMS), triethoxysilane (TRIES) and tetramethyldisiloxane (TMDSO); and VT-type prepared by VTMS and TRIES) that consisted of a Si–C–C–Si unit created by the hydrosilylation of vinyl and hydrosilyl groups in a Si precursor were fabricated at temperatures higher than 300 °C under N2. Single-gas permeation properties for SiOC membranes at temperatures ranging from 100–500 °C were examined to determine the effect of a silica precursor on the size of an amorphous network. A SiOC membrane (VTT-type) fabricated at 400 °C under N2 showed a H2 permeance of 5.3 × 10−7 mol m−2 s−1 Pa−1 with H2/CO2, H2/N2, H2/CH4 and H2/CF4 permeance ratios of 5.6, 15, 18 and 485, respectively, at 400 °C. The permeance of H2 for a VTT-type membrane heat-treated at 550 °C in air significantly increased from 5.3 × 10−7 to 2 × 10−6 mol m−2 s−1 Pa−1 with a decrease in the H2/CF4 permeance ratio from 485 to 90 due to the combustion of the CH3 groups. The SiOC membrane (VT-type) showed high thermal stability in air at 550 °C with a H2 permeance of 3.0 × 10−7 mol m−2 s−1 Pa−1 and H2/CH4 and H2/CF4 permeance ratios of 50 and 400, respectively, at 400 °C.

A mineral carbonation process for CO2 sequestration has been developed, and its process feasibility was examined based on laboratory-scale experimental studies. The process is composed of four steps: (i) extraction of calcium ions from waste cement powder with nitric acid. (ii) Absorption of CO2 in sodium hydroxide solution from CO2 emission sources. (iii) Precipitation of calcium carbonate particles by mixing the calcium leached solution and the CO2 absorbed solution. (iv) Regeneration of nitric acid and sodium hydroxide from the remaining solution of sodium nitrate from step (iii) with bipolar membrane electrodialysis. The regenerated acid and alkali can be reused in steps (i) and (ii) with newly fed waste cement powder. The overall mass balance of the process is the input of CO2 and calcium and the output of calcium carbonate and residues of the leaching. The effects of the operation conditions in the calcium leaching step (i) and regeneration step (iv) were experimentally investigated with a laboratory-scale experimental apparatus. It was found that calcium leaching can be easily and quickly performed with nitric acid, and high-purity calcium carbonate can be obtained when the operation conditions are set to obtain a final pH of about 7. Regeneration of nitric acid and sodium hydroxide were favourable when the current density and the electric potential were high and the feed concentration was low in terms of the power consumption. Thus, the total process can be operated under appropriate conditions, and its CO2 fixation performance was evaluated.

The local fire department executed a training simulation for chemical and explosive incidents at a large sports facility. In this training simulation, a physician-staffed helicopter arrived at the request of the fire department and landed just outside the cold zone in the parking area. The doctor and nurse of the helicopter were escorted to a red area in the cold zone, which was selected based on the results of postdecontamination triage. After the patients had been treated, they were air medically evacuated to the base hospital. In the Tokyo subway sarin attack in 1995, St Luke's International Hospital admitted over 600 victims. During this incident, 23.2% of medical staff suffered secondary injury from sarin exposure. If air medial crews respond with subsequent postexposure effects during flight, an affected pilot could lose control of the helicopter, resulting in a fatal crash. Based on potential safety concerns for air medical and ground personnel, our recommendation would be that air medical helicopters not be dispatched to sites of chemical, biological, radiological, nuclear, and explosive incidents.

The removal of water vapor from humid gas streams is important for steam recovery in power plants and reaction enhancement in a membrane reactor that produces water as a by-product, and so on. The prospect of future applications for organosilica membranes in these fields prompted the present investigation of humid gas separation properties via 1,2-bis(triethoxysilyl)ethane (BTESE)-derived membranes. In this work, binary humid gas separation (H2O/H2 and H2O/N2) was performed on BTESE-derived membranes at temperatures ranging from 80 to 200 °C under feeds of water mole fractions ranging from 0.1 to 0.9. Permeance and the permeance ratios of H2O/H2 and H2O/N2 were confirmed to be dependent on temperature and vapor pressure, and found to be correlated using the water adsorption potential, which accounted for both the temperature and the vapor pressure. The highest levels of water permeate flux, permeance, and permeance ratios of H2O/H2 and H2O/N2 were 37 kg/(m2 h), 5.5 × 10−6 mol/(m2 s Pa)), and 84 and infinity (>6700), respectively, at 150 °C where the partial pressure difference of water across the membrane was 107 kPa. The high performance of BTESE-derived organosilica membranes shows promise for their future applications in humid gas separation at moderate-to-high temperatures.

Ultrathin, defect-free organosilica membranes on porous commercialized polymeric nanofiltration membranes (polythersulfone, PES) were fabricated via flow-induced deposition (FD) with a rinse step. Herein, we compare the FD approach with and without the rinse step and describe the effect on the formation of BTESE layers, along with separation performances during the vapor permeation (VP) dehydration of isopropanol (IPA)/water solutions (IPA: 90 wt%). The rinse strategy of reducing the BTESE layer (less than 100 nm) effectively enhanced the membrane permeance without compromising selectivity. The rinsed membrane showed high water permeance (1.8 × 10 −6 mol m −2 s −1 Pa −1 ) that almost equaled that of a polymeric support (2.0 × 10 −6 mol m −2 s −1 Pa −1 ), and a separation factor of about 800 for this VP process at 105 °C (1.1 wt% IPA in the permeate side). Moreover, these membranes demonstrated stable permeation properties under surroundings that included both vapor and liquid for the VP and pervaporation dehydration of IPA/water mixtures under high temperature. The membranes also demonstrated fine flexibility in a vast array of bending radii (more than 1.5 mm). This work has shown that the rinse process is an effective strategy for fabricating an ultrathin organosilica top layer on porous polymeric supports via the FD approach.

Introduction:The management of chemical and explosive events is critical to reducing morbidity and mortality. However, initial patient care considerations and protective actions for staff are unfamiliar to most frontline clinicians.Methods:This study evaluated an Incident report.Results:On December 1, 2017, a factory of chemical industries in Japan exploded. Dust forming as a byproduct from the crushing and packing process of the resin for ink exploded at the facility. A local fire department requested the dispatch of two physician-staffed helicopters (known as a doctor helicopter [DH] in Japan). The first party of emergency services established a headquarters and first-aid station. However, this area was feared to be at risk of a second explosion. Physicians performed re-triage for all 11 burned patients. Three severely injured patients were transported to emergency medical service centers either by ground ambulance or the DH without undergoing any decontamination. The physician who escorted the patient by ground ambulance complained of a headache. One of the severely injured patients was treated at a local hospital and then transported to an emergency medical service center after undergoing decontamination and intubation. Fortunately, all patients who were transported to medical facilities obtained a survival outcome.Discussion:Chemical, biological, radiological, nuclear, and explosive incidents are rare, but can be fatal for responders to this kind disaster. As such, all who work at such scenes should be prepared and train adequately to ensure they have the knowledge and skill to both manage patients and protect themselves from harm.

A spray-assisted, 2-step interfacial polymerization (IP) of trimesoyl chloride (TMC)/ m -phenylenediamine (MPD) was proposed for the preparation of polyamide (PA) membranes. In the first step, TMC/hexane solutions were sprayed onto MPD-impregnated polysulfone (PSf) supports for 10–60 s, followed by a second step where the first-step membranes made contact with the TMC/hexane solutions. It is noteworthy that water permeability was increased with spray time in the first step of the 2-step IP, showing approximately doubled values at the spray time of 20–30 s, compared with 1-step PA/PSf composite membranes, while NaCl rejections were practically unchanged. With longer spray time (30–60 s), water permeability decreased while NaCl rejection remained at the same level. A characterization of 1- and 2-step PA membranes, including FE-SEM and ATR-FTIR, revealed the formation of multilayered ridge-and-valley structures of polyamide from the spray-assisted IP steps, and it is suggested that the increased water permeability have been caused by the increased interfacial surface area of the 2-step PA membranes.

Using 1,2-bis(triethoxysilyl)ethane (BTESE) as the precursor and 1-propanol as the solvent, a uniform and defect-free hybrid organosilica thin coating was successfully deposited onto polysulfone (PSF) film via a sol–gel process using spin coating. The structural characterization, morphology and surface wettability of the BTESE-derived silica coating on PSF film were investigated. Results showed that the outermost layer of the composite film consisted of nanoscale hybrid organosilica networks that were approximately 200 nm in thickness with a low surface roughness. In addition, the measured water contact angle of the composite film decreased from 78.8° to 45.5°, which showed that the surface wettability of the BTESE-coated PSF composite film was also improved.

Plasma enhanced chemical vapor deposition (PECVD) was applied to the fabrication of hexamethyldisiloxane (HMDSO) derived amorphous silica membranes. Three different PECVD procedures, namely, Ar-PECVD, O 2 -PECVD, and a 2-step PECVD sequence involving Ar-PECVD followed by O 2 -PECVD, were employed to determine the effect of carrier gas on membrane structure and gas permeation property. The membrane prepared by Ar-PECVD showed moderate molecular sieving properties at room temperature (permeance ratio of 15 for He/N 2 and 220 for He/SF 6 ), but was easily decomposed at high temperatures. For the case of the O 2 -PECVD membrane, the permeance of small molecules such as He and H 2 increased with increasing temperature, while the permeance of large molecules such as N 2 and SF 6 was consistent with Knudsen diffusion, and thus the selectivity of He/N 2 increased up to 81 at 500 °C. Compared with Ar- and O 2 -PECVD, 2-step PECVD membrane showed a excellent molecular sieving properties. Since the 2-step membrane was treated by O 2 -PECVD in the second step of the sequence, a good thermal stability was confirmed at temperatures as high as 400 °C. The 2-step PECVD membrane showed high He and H 2 permeances of 5.2×10 −7 and 2.4×10 −7 mol/(m 2 s Pa), respectively, with He/N 2 and H 2 /N 2 permeance ratios of 4200 and 1900 at 400 °C, respectively. The results suggested that the 2-step PECVD is applicable to the low-temperature fabrication of thermally stable molecular sieving amorphous silica membranes.

A new type of process for separating metals in solution, based on bipolar membrane electrodialysis coupled with metal-ion chelation, is proposed. The method was applied to a mixed solution of lithium and cobalt, as in the recycling of waste lithium-ion batteries. When a chelating agent, ethylenediaminetetraacetic acid (EDTA), was added to a mixed solution of lithium ions and cobalt ions, almost all the cobalt ions were chelated by EDTA to form anions, whereas lithium ions were hardly chelated, at pH > 4. Electrodialysis of the feed solution was conducted using a three-cell-type electrodialysis system, with a unit consisting of two ion-exchange membranes and a bipolar membrane. Lithium was transported to the lithium recovery cell and cobalt was transported to the cobalt recovery cell, using an applied electric field. The selectivity for each metal in the recovery cell was about 99%. The effects of initial EDTA concentration and pH were examined. Absorption of metal ions in the ion-exchange membranes was observed; this can be avoided by using a continuous semi-batch operation.

Dissolution rates of alkaline rocks, including wollastonite (CaSiO3), olivine (Mg2SiO4), and phlogopite (KMg3AlSi3O10(OH)2), with high pressure aqueous CO2 solution were measured to examine the feasibility of CO2 fixation via carbonation. Influence of solid/liquid ratio (1.0–10 g/250 mL), temperature (303–353 K), and CO2 pressure (1.0–3.0 MPa) on the extraction rates of calcium or magnesium ions was investigated. Under the experimental conditions studied, the calcium ion extraction rate from wollastonite was the highest among the three rock samples studied. The calcium concentration reached about 120 mg/L, and about 12% of the calcium in wollastonite sample was extracted after 60 min at 353 K with 1.0 MPa CO2. The calcium and magnesium extraction ratios from the alkaline rocks were much lower than those from waste concrete powder. Increasing the extraction time and temperature would be an effective way to promote calcium extraction from wollastonite.

The virtual structures of organic–inorganic hybrid silica membranes were prepared on a computer by introducing two different types of organic functional groups into a conventional silica network. bis(triethoxysilyl)ethane (BTESE) and bis(triethoxysilyl)ethylene (BTESEthy) derived silica-based organic–inorganic hybrid microporous materials were modeled and their structures such as pore size distribution and radial distribution function were studied. Adsorbability of water and diffusivity of helium molecule was also examined. Both the hybrid silica structures showed larger pore size than pure silica. The difference in water adsorption performance and helium diffusivity was observed between two types of hybrid silica structures. BTESEthy silica showed higher loading of adsorbed water and it is expected to be a promising material for water treatment. Helium diffusivity in BTESEthy silica was greater than that in BTESE silica, which was in consistent with the micropore size.

A promising layered-hybrid membrane consisting of a microporous organosilica active layer deposited onto a porous polymer support was prepared via a facile sol-gel spin-coating process. Subsequently, the pore sizes and structures of the organosilica top layers on the membrane surface were tuned at mild temperature combined with vapor treatment from either hydrochloric acid (HVT) or ammonia (AVT), thereby tailoring the desalination performance of the membranes during reverse osmosis (RO) processing. The effects of HVT and AVT on the pore size, structure, and morphology of organosilica layers and on the separation performances of membranes were investigated in detail. We confirmed that both HVT and AVT processes accelerated the condensation of silanol (Si-OH) in the organosilica layer, which led to dense silica networks. The layered-hybrid membranes after HVT showed an improved salt rejection and reduced water flux, while membranes after AVT exhibited a decrease in both salt rejection and water permeability. We found that HVT gave rise to smoother and denser organosilica layers, while AVT produced large voids and formed pinholes due to Ostwald ripening. These conclusions were supported by a comparative analysis of the results obtained via FTIR, TG-MS, SPM, and RO desalination.

Process design and cost estimation were conducted for CO2 recovery by liquid absorption with alkaline solution, coupled with bipolar membrane electrodialysis for CO2 gas separation and alkaline solution regeneration. The electrodialysis performances and power consumption for CO2 recovery and alkaline solution regeneration were examined using laboratory-scale electrodialysis equipment under various conditions; degree of CO2 absorption, CO2 recovery ratio, alkaline concentration, and type of cation exchange membrane. The total cost of CO2 recovery was estimated for the treatment of CO2 emitted from a 400 MW coal-fired thermal power plant. The minimum cost for the optimum condition was about US$180 per ton-CO2 removed, which is higher than that for the conventional process using amine absorption and thermal desorption. However, a sensitivity analysis indicates that the overall cost could be significantly reduced if the cost of membranes was reduced.

Bipolar membrane electrodialysis (BMED) was used to remove boron from aqueous solution. BMED was compared with conventional electrodialysis (ED) using aqueous solutions of sodium tetraborate containing 100 mg/L of boron. With use of BMED, more than 90% of the boron was removed under both acidic (pH 2.3) and basic (pH 9.1) conditions, whereas only 35−45% of the boron was removed using conventional ED. Over 90% of the boron was removed from the diluate solution over a wide range of initial pH from 2.3 to 12.0. A high initial pH reduces the current efficiency of boron removal because of the high mobility and high concentration of hydroxide ions compared with those of borate ions. The power requirement for boron removal increased as the initial pH and concentration of sodium chloride increased, but decreased as the applied voltage was increased. BMED is a promising option for removal of boron from aqueous solution.

We evaluated a reaction process in which waste concrete was used to recover phosphorus from wastewater. We conducted experiments using various actual wastewater samples obtained by the sludge dewatering process at a sludge disposal plant. The removal ratios of orthophosphate ions from actual wastewater samples were higher than those in the case of model wastewater for which the initial concentrations of orthophosphate ions (131–161 mgP L−1) were equal to those for the actual wastewater sample and the Ca/P ratio (approx. 5 g g−1). This result indicates that the high concentration of calcium ions originally contained in the wastewater samples promotes the reaction of HAP. The novel phosphorus recovery process developed in this study, which is based on the use of waste concrete, has the potential to contribute to the inexpensive recycling of phosphorus resources.

Bipolar membrane electrodialysis is applied to CO2 recovery from alkaline carbonate solution. CO2 in flue gas is captured by an alkaline hydroxide absorbing solution to form an alkaline carbonate solution. The captured CO2 is recovered from the alkaline carbonate solution via bipolar membrane electrodialysis, and the alkaline solution is regenerated simultaneously. To reduce the power requirement for CO2 recovery, this study considers optimal design and operation. Three membrane arrangements were compared, and the results indicate the membrane arrangement comprising a bipolar membrane and cation exchange membrane is the most energy saving. With further optimization of operation conditions, the minimum power requirement for CO2 recovery was reduced to 2.1 MJ/kg-CO2 (or 2.1 GJ/t-CO2). © 2009 American Institute of Chemical Engineers AIChE J, 2009

下水処理施設からのリン回収法として，コンクリート廃棄物を用いる新規な晶析プロセスを提案した．下水のモデル水溶液（リン酸二水素カリウム水溶液）と廃セメント微粉末を用いた回分式析出反応実験をすることによりプロセスの実現可能性を検討した．汚泥脱水時の余剰水（汚泥返送水）に近いリン濃度（50 mgP L−1）の水溶液に廃セメント微粉末を1.0 g L−1入れた実験では360 minで50%のリンが除去された．またpHの上昇とカルシウム濃度の上昇が確認され，表面反応と水酸化カルシウムの溶出という2通りの反応メカニズムが示唆された．240 h反応させた試料のSEM画像解析と，X線回折分析の結果からは，リンがHAP（Hydroxyapatite）として廃セメント表面に析出していることが示唆された．反応速度はコンクリート塊を用いる場合に比べて数倍となった．また既往のHAP晶析法の実験と比較しても，同程度の反応速度が得られた．既往のHAP晶析法では，リン鉱石やケイ酸カルシウムなどの種結晶のほかに塩化カルシウムなどのカルシウム薬剤を必要とするが，これらをコンクリート廃棄物で代用することにより更なるコスト削減が期待できる．またコンクリートの骨材再生時に余剰物として発生する廃セメント微粉末は反応性が高く骨材を含まないため，コンクリート破砕物をそのまま用いるよりも更に高い反応速度を得ていると考えられた．

A new concept was proposed to control the pore size in a novel silica membrane. The tuning of the pore sizes in triethoxysilane (TRIES)-derived membranes was successfully conducted via an in situ reaction between NH3 and Si–H groups at high temperatures. The formation of Si–NH2 and/or Si–NH groups in the silica structure enhanced the hydrogen selectivity.

Copolymers composed of 5-acryloyloxypentyl cholesterate (Ch5A) and acrylic acid (AA), poly(Ch5A-co-AA)s, were prepared changing their molar ratio, and their mesomorphic behaviors were investigated. Wide- and small-angle X-ray diffraction studies showed that poly(Ch5A-co-AA)s with a Ch5A mole fraction, F, of 0.20 and larger showed the smectic A phase in which side chains are arranged perpendicularly to the main-chain axis forming bilayers. The structural ordering and the clearing temperature, Tc, increased with decreasing F. The copolymers with F of around 0.10 exhibited a mesophase showing extremely high Tc and longer periodic spacing than the SmA phase. The copolymers of F = 0.05 and higher were not dissolved in water but swelled to form hydrogels with mesomorphic properties, presumably due to the physical cross-linking of hydrophobic aggregates of Ch5A side chains. The relationship between the uncommon thermotropic behavior and the mesomorphic structure formed by the specific interaction of chiral Ch5A ...

We manufactured a prototype long-life PHC messenger wire with high-strength and high-conductivity Cr-Zr Precipitation-Hardened Copper alloys to reduce the maintenance costs of overhead catenary system. We are now testing it for corrosion-resistance and durability in a tunnel subjected to water leakage and a section suffering from salt damage between Tsukumi and Azamui on the Nippo line, JR Kyushu. In a spot observation after it was used for seven years, we found that it had no significant corrosion.

It has become very important to correctly grasp the contact loss between contact wire and pantograph, evaluate the current collection performance and diagnose the overhead contact line equipment of electric railroads. Although some methods have already been developed to measure contact line, they are not practical because of the restriction, on measurement accuracy, by noise. A new method was devised to measure contact loss from feeble current changes produced between a pantograph and the ground at the moment of contact loss. The new method uses a no current collection pantograph of inspection car used for Shinkansen AC electric railroads. In the examination by an inspection car installed with the measuring equipment, it was confirmed that it was possible to obtain good response to contact loss.

An overhead contact line inspection system that can be installed on a rail-and-road car has been developed. It consists of a small size contact wire wear measuring instrument and a small size pantograph with various sensors. It can be used in the daytime at the maximum inspection speed of 30 km/h, which is limited by car running stability. From the results of laboratory and field tests, it is proved that wear measurement is accurate enough for practical use.

This study describes a low-energy atom scattering system that was combined with a time-of-flight spectrometer for insulator surface structural analysis. We show one example. MgO(001) crystal was used to study the surface analysis technique and is illustrated here. Insulator surface structure is difficult to study because of the charging effects during electron or ion-beam bombardment. Nevertheless, structural analysis of insulator surfaces is very important in fundamental research as well as in technology fields.

For the maintenance of overhead contact line, it is important to know the exact state of contact wire wear in electric railways. A new type of measuring apparatus has been developed which is sufficiently small to be installed on the roof of commercial car. The apparatus has an optical system composed of sodium vapor lamps and CCD line sensor cameras with optical filters. This apparatus detects the width of wear surface of wire, and calculates the residual height from the width. The measuring frequency of the cameras is 1 kHz. The new apparatus has been tested in a laboratory and in the field by using an inspection car.

2,4,6-Tris[3(triethoxysilyl)-1-propoxy]-1,3,5-triazine (TTESPT) is a new precursor for preparing membranes. The TTESPT-derived silica membrane exhibits a significant degree of selectivity for C3H6–C3H8 ∼37 at a permeation temperature of 50 °C, which greatly surpasses the upper-bounds of selectivity and permeance trade-off of carbon membranes. This indicates the potential for further development toward C3H6–C3H8 separation applications.

The sol–gel method was applied to Al-doped bis (triethoxysilyl) methane (BTESM, Si–C–Si unit) membranes. High C3H6 : C3H8 permeance ratios of approximately 40 at 200 °C were achieved through the precise control of the silica network size via a spacer method using Si–C–Si units as well as the incorporation of Al in BTESM-derived networks.