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In this study, the structural factors controlling the enzymatic saccharification of rice straw cellulose were examined by preparing structure-modified rice straw samples such as dewaxed, alkali-treated, oxidized, and swollen rice straw. It was found that the initial enzymatic saccharification rate of the various structure-modified samples was largely controlled by the initial cellulose surface area of the cellulose unit. Although the presence of lignin limited the cellulose surface area, there was no strong relationship between the lignin content and the initial reaction. On the other hand, the long-term enzymatic saccharification of rice straw cellulose highly depended on the lignin removal rate (lignin content). It was also found that silica is not a crucial factor in controlling the enzymatic saccharification. [ABSTRACT FROM AUTHOR]

Ground water contaminated with trichloroethylene (TCE) used in electronic, electric, dry cleaning and the like industries is often treated by air-stripping. In this treatment process, TCE in its vapor form is stripped from ground water by air stream and sometimes emitted into the atmosphere without any additional treatments. Activated carbon adsorption is one of the practical and useful processes for recovering the TCE vapor from the exhaust air stream. However, adsorption of the TCE vapor from the stripping air stream onto activated carbons is not so simple as that from dry air, since in the exhaust air stream the TCE vapor coexists with water vapor with relatively high concentrations. The understanding of the adsorption characteristics of the TCE vapor to be adsorbed on activated carbon in the water vapor-coexisting system is essential for successfully designing and operating the TCE recovery process. In this work, the adsorption equilibrium relations of the TCE vapor adsorption on activated carbons were elucidated as a function of various relative humidity. Activated carbon fibers (ACFs) were used as model activated carbon. The adsorption equilibrium relations were studied by the column adsorption method. The adsorption isotherms of TCE vapor adsorbed on sample ACFs were successfully correlated by the Dubinin–Radushkevich equation for both cases with and without coexistent water vapor. No effects of coexistent water vapor were found on the limiting adsorption volume. However, the adsorption characteristic energy was significantly reduced by the coexistence of water vapor and its reduction was successfully correlated with the equilibrium amount of water vapor adsorbed under the dynamic condition. [Copyright &y& Elsevier]

The conversion of plant biomass-based solid wastes in pressurized hot water is a promising method by which to obtain certain chemicals, e.g. sugars and furfurals. However, it is relatively difficult to optimize reactions in pressurized hot water, that is, the so-called hydrothermal reaction process, because the reactions have less selectivity than other conversion methods and involve a significant number of paths. It is therefore highly desirable to achieve a greater understanding of the reaction mechanisms and kinetics of plant biomass under hydrothermal conditions. This paper discusses the application of novel liquid-phase thermogravimetry to investigate the reaction kinetics of some existing plant biomass-based solid wastes, such as old newspaper, rice husk and spent malt from a brewery, under hydrothermal conditions. This thermogravimetric measuring system is equipped with a magnetic suspension balance that can measure the weighing force without direct contact between the sample load cage and the main body of the balance, and is thus able to observe the weight decay in the liquid phase over a temperature range up to 300 °C at 10 MPa. Kinetic parameters for the hydrothermal reaction of the biomass-based materials were successfully determined through analysis of the obtained gravimetric data. [Copyright &y& Elsevier]

The release kinetics of esterified p -coumaric acid (PCA) and ferulic acid (FA) from rice straw under a mild alkaline condition were investigated to collect fundamental data for the design of a recovery process. The results showed that the straw size, NaOH concentration, and temperature were the key parameters governing release kinetics. The analysis demonstrated that FA is released considerably faster than PCA. The close relationship between lignin and the PCA dissolution indicates a reciprocal and/or simultaneous release. Moreover, PCA is broadly distributed in the lignin network but tends to be located more densely in the lignin fraction which is not easily solubilized by alkaline treatment. In contrast, the release of FA is strongly affected by removal of lignin fraction which is easily solubilized. These results suggest that the release kinetics are controlled by the accessibility of NaOH to their ester sites in the lignin/hemicellulose network, and by their localization. [ABSTRACT FROM AUTHOR]

Abstract: Here, a simple cellulose conversion model that considers the cellulose surface area and surface density of adsorbed cellulase as substrate-derived and cellulase-derived factors controlling reaction rates is provided. Microcrystalline cellulose (Avicel) and delignifed softwood were used as controls, and structure-modified samples were prepared. It was shown that the initial cellulose conversion rate is largely controlled by the cellulose surface area. Moreover, the proposed model demonstrates that increases in cellulose surface area reduce retardation of the cellulase reaction. The proposed model was used to estimate the impact of structural changes in a substrate (i.e., cellulose surface area) by pre-treatment on enzymatic saccharification. It was found that increasing the cellulose surface area is the most effective way to optimize enzymatic saccharification of cellulose substrates. [Copyright &y& Elsevier]

Abstract: In this work, we found that Tween 20 treatment (0–8mM) contributed to the cell wall collapse of most samples except for those with high lignin contents and high crystallinity. Cell wall collapse contributed to the formation of 10- to 50-nm pores and not only increased the monolayer saturation amount of adsorbed cellulase about 3–3.6 times but also increased the cellulase adsorption rate (D e/r 2) about 160–880 times. Moreover, cellulose conversion at 72h was also increased 8.7–21.5% by Tween 20 treatment. On the other hand, the adsorption of Tween 20 on Avicel (microcrystalline cellulose) hindered the cellulase reaction (adsorption and saccharification). The effect of Tween 20 treatment on the crystalline part was insignificant for both lignocelluloses and Avicel. It was found that some degree of pretreatment (e.g. lignin removal) that enhances Tween 20 diffusion into samples is necessary to obtain the structural effects of Tween 20. [Copyright &y& Elsevier]

Abstract: Turbostratic carbon nanofibers (CNFs) with a rough surface, open pore walls, and a defect structure were continuously produced by the thermal decomposition of alcohol in the presence of an iron catalyst and a sulfur promoter at 1100°C under a nitrogen atmosphere in a vertical chemical vapor deposition reactor. A graphite exfoliation technique using intercalation and thermal shock was employed to expand the graphene layers of the as-produced turbostratic CNFs. The hydrogen storage capacity of the turbostratic CNF samples was measured using the volumetric method with a pressure of up to 1MPa at 77K. The hydrogen storage capacities of the as-produced and exfoliated turbostratic CNFs were 1.5 and 5wt%, respectively. The defects on the surface and expandable graphitic structure are considered important keys to increasing the hydrogen uptake in turbostratic CNFs. [Copyright &y& Elsevier]

Abstract: We have developed activated carbon membranes (ACM) that can remove not only particulate matters but also dissolved organic matters. Recently, we succeeded in growing carbon whiskers on activated carbon membranes (W-ACM). We hypothesize that the whiskers prevent the flux from lowering due to particle blocking on the membrane surface. In this study, we compared the filtration properties and blocking characteristics of ACM and W-ACM using an artificial microsphere (polymethyl methacrylate) (PMMA), particle diameter=0.8, 5, and 10μm) to estimate the effect of whiskers on particle filtration. We found that the whiskers successfully prevented a reduction of penetration flux in all particle diameters; however, the prevention mechanism seems to be different according to the filtrated particle size. To clarify the mechanism, we performed numerical model analysis using a microfiltration model. In the case of 0.8μm particle filtration, whiskers seemed to inhibit the packing of particles into the microholes existing at the surface of activated carbon membrane, and with 5–10μm particle filtration, the packing density of the cake layer accumulated on the membrane would be reduced with the appearance of whiskers. [Copyright &y& Elsevier]

A simple double-layered coculture system using Caco-2 cell and Hep G2 cell, which mimic metabolic processes occurring in humans such as absorption through the intestine and cytochrome P450 1A1/2 involving biotransformation in both the intestine and liver cells, was used to investigate the toxicity of model chemical, benzo[a]pyrene (B[a]P). It was found that both Caco-2 and Hep G2 cells can metabolize B[a]P to toxic metabolites including B[a]P-7,8-hydrodiol (7,8-diol), an immediate precursor to the highly-reactive ultimate toxicant of B[a]P, B[a]P-7,8-hydrodiol-9,10-epoxide (BPDE), possibly mediated by cytochrome P450 1A1/2 activity. However, in a double-layered coculture system, no significant reduction of Hep G2 cell viability was found, although an approximately 50% reduction in viability was observed in pure Hep G2 cells. HPLC analysis showed that Caco-2 cells transfer B[a]P and its toxic metabolites back to the apical side, thus decreasing the concentrations of toxic metabolites including B[a]P-7,8-hydrodiol (7,8-diol) in cocultured Hep G2 cells. These results appear to be correlated with in vivo data on the effects of orally administered B[a]P, that is, low (10%) bioavailability in the rats and almost no acute lethal toxicity in rats or mice. As such, the simple double-layered coculture system can provide more accurate information regarding the toxic actions of the hazardous chemicals in humans than a pure culture system, as it also gives the final toxicity as a result of many complicated phenomena such as selective permeation in the intestine and biotransformation in the intestine and liver. [Copyright &y& Elsevier]

To investigate particularly organ-to-organ interactions against the exogenous stimuli, two coculture systems, i.e. a simple double-layered static coculture system and a perfusion coculture system consisting of Caco-2 and Hep G2 cells to mimic the metabolic processes occurring in the small intestine and the liver, were used. The induction of cytochrome P450 (CYP) 1A1/2 was measured to estimate the metabolic capacity of Caco-2 and Hep G2 cells against tested chemicals.In both coculture systems, the inducibility of CYP1A1/2 by benzo[a]pyrene (B[a]P) or 3-methylcholanthrene (3-MC) in terms of ethoxyresorufin O-dimethylase (EROD) activity was more remarkable than expected from the individual cell cultures. It seemed to show possible organ-to-organ interactions in terms of the physiological protection of human body against exogenous stimuli. Therefore, we can say that a real-time combined system is really important to predict the complicated phenomena in human because an individual culture system cannot represent the organ-to-organ interaction and also coculture systems can give information of final metabolic activity as a result of many complicated phenomena. [Copyright &y& Elsevier]

A novel composite membrane consisting of an activated carbon membrane with filamentous carbon, applicable to water treatment, was fabricated by a combination of conventional carbonization and thermal deposition. The carbonization was performed after dipping a ceramic support in a latex polymer followed by the application of ferric sulfate [Fe2(SO4)3·nH2O] catalyst. This was followed by CVD from methane at 1050–1100 °C. The resulting membrane therefore consisted of a filamentous carbon layer grown with a combination of the catalyst and deposited hydrocarbon, and an activated carbon layer on a ceramic support. These structural characteristics were confirmed by means of the cut-off of dextran molecules, the pure water permeability, SEM, and the adsorption of phenol. Water treatment experiments using phenol and poly(methyl methacrylate) as model pollutants indicated that this membrane was able to remove dissolved organics of low molecular weight and suspended solids. Also, the filamentous carbon layer successfully prevented the fine particles from sticking on the external surface of the membrane by frequent back washing. [Copyright &y& Elsevier]

An 80-cm long tubular carbon coated membrane was fabricated by chemical vapor deposition (CVD) of methane on a multilayered porous ceramic substrate at a temperature of 1000 °C. The deposition of pyrocarbon on the membrane generated a carbon film, the nature of which not only reduced the pore size of the membrane but also changed the physical properties of the membrane, including its hydrophobicity, electrical conductivity, and thermal conductivity. To ensure a uniform deposition of carbon on the membrane, a CVD apparatus equipped with process piping was employed to periodically reverse the direction of the gas flow in the reactor. The CVD experiments were then conducted by varying parameters such as the rate of flow of the gas mixture (methane and nitrogen), the percentage concentration of methane, and so on. To analyze the uniformity of the carbon film, we measured the electrical resistance of the membrane and the permeation of six gases through the sectioned membranes. In the range of our study, it was found that the flow rate of the gas mixture and the alternation of the direction of the gas flow were two important factors for determining the uniformity of the carbon deposit in the membranes. Observation by scanning electron microscope (SEM) and measurement of the nitrogen permeation of the membranes revealed that fabrication of uniform carbon coated ceramic membranes with a desired pore size is possible for applications involving microfiltration, ultrafiltration, and nanofiltration. In addition, the utilization of the superior properties of the membranes such as hydrophobicity and electrical conductivity were suggested for enhancing the degree of separation of the membranes. [Copyright &y& Elsevier]

Lignin is a renewable resource that can generate a variety of value-added benzene derivatives during hydrothermal and/or chemical hydrolysis treatment; the crucial task is to separate the targeted derivatives from the hydrolysate. This study aims to investigate the adsorption kinetics of lignin-derived benzene derivatives onto silicalite-1 crystal in an aqueous-phase system to examine the potential applicability of silicalite-1 to aqueous-phase kinetic separation. Functional groups substituted to benzene include –OH, –CH 3 , –CH 2 –CH 3 , –OCH 3 , –CHO, –COOH, and –CH 2 =CH 2 –COOH. First, the corrected diffusivity was compared among cresol isomers. Critical diameter of the isomers was found to be a key parameter, giving rise to significant differences in diffusivity. Interestingly, we also discovered a considerable difference (maximum over 4 orders of magnitude) in corrected diffusivity, even among mono - and para -substituted derivatives, although these sorbates have the same critical diameter. In particular, the carboxylic derivatives tended to exhibit extremely low diffusivities and to show S-shaped isotherms. The diffusivities were strongly affected by the melting point of the sorbates. These results indicate a strong sorbate-sorbate interaction (e.g., hydrogen-bonding between carboxylic groups) that considerably limits molecular mobility in the narrow channel. Our findings are relevant to research on silicalite-1 to aqueous-phase kinetic separation. [ABSTRACT FROM AUTHOR]

A simple ethanol concentration process composed of a simple adsorptive apparatus using a single adsorbent, i.e., molecular-sieving carbon (MSC), is proposed for small-scale bioethanol production. The process designed to comprise pre-concentration of ethanol through gaseous-phase adsorption onto MSC and selective dehydration driven by molecular-sieving during desorption was tested under various conditions. Among the candidate adsorbents, MSC 5A showed the highest maximum ethanol adsorption capacity (0.163 g g −1 ). It was confirmed that the adsorption temperature and the initial ethanol concentration in the broth are crucial factors for the adsorption stage. For the desorption stage, the water recovery temperature significantly affected the final ethanol concentration and the ethanol recovery. As a practical option for the application of the proposed system, sequential batch fermentation and ethanol recovery was successfully demonstrated. [ABSTRACT FROM AUTHOR]

In this study, molecular sieving carbons (MSCs) for biogas upgrading were successfully fabricated by a simple temperature controlled carbonization of moso bamboo ( Phyllostachys pubescens ) without energy consuming steps (i.e. char activation and pore modification). As the carbonization temperature increased from 600 to 900 °C, the specific surface area of bamboo charcoals increased and the pore size distribution of bamboo charcoal became narrower and closer to the dimensions of CH 4 (0.38 nm). Bamboo charcoals had a more disordered carbon stacking structure than commercial MSC and contained more surface oxides, which contribute to greater surface reactivity than commercial activated carbon. Bamboo charcoal carbonized at 900 °C had the highest CO 2 adsorption capacity (121.6 g kg −1 ), even higher than commercial MSC (102.88 g kg −1 ). Despite the poor kinetic CO 2 adsorption properties of bamboo charcoals compared to commercial MSC, synthetic biogas (60% CH 4 + 40% CO 2 ) was successfully upgraded to concentrated CH 4 (>90%) by small-scale pressure swing adsorption using bamboo charcoal. It is expected that bamboo charcoals can contribute to sustainable small-scale biogas upgrading. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) were formed by liquid-phase exfoliation in an ultrasonic bath using platelet graphite nanofibers (PGNFs) as the raw material and dimethyl sulfoxide (DMSO) as the exfoliation agent. PGNFs, carbon fibers with graphene nanosheets stacked perpendicular along the fiber axis, were sectioned layer by DMSO for 3 h with ultrasonic assistance to create GQDs. The diameters of the derived GQDs were in the range of 10–30 nm and fewer than five graphene layers were formed. X-ray photoelectron spectroscopy analysis revealed that no functional groups were grafted onto the GQDs during the process, indicating that the synthetic route produced high-quality GQDs. [ABSTRACT FROM AUTHOR]

Fermentation profiles of four different yeasts reportedly defective in sucrose utilization indicate that all strains tested removed particular sugar via selective conversion to ethanol in a saccharide mixture. At the temperature of pressed sugarcane juice, Saccharomyces dairenensis and Saccharomyces transvaalensis performed better in ethanol production rate and yield, respectively. [Copyright &y& Elsevier]

Abstract: A double-sided surface light source based on field emission (FE) using an alternating current power source is demonstrated. Carbon-nanotube (CNT) emitters and ZnS phosphor are mixed and screen-printed onto two pieces of indium tin oxide glass that were assembled together with the coated surfaces facing each other to make a parallel-plate, diode-structure FE device. The device has a double-sided luminance distribution with a turn-on field of 2V/μm, a good uniformity, and a stable luminance of 4000cd/m2. The results show that CNTs not only act as good field emitters but also as an electrically conductive network around the isolated phosphors. The network prevents electric arcing and thus extends the lifetime of the device. [Copyright &y& Elsevier]

Abstract: High yield sugarcane is expected to resolve the competition between food and fuel regarding farmland and biomass resources. However, its higher composition of reducing sugars (i.e., glucose and fructose), which inhibit sucrose crystallization, hinders the production of sugar from high yield sugarcane. Under the conventional integrated sugar–ethanol manufacturing system, high biomass yield causes only the increase of ethanol production because of the increase in unrecovered sugar after extraction, which represents a failure in resolving the competition. The technology presented here is the world''s first to solve this problem via selective ethanol fermentation using Saccharomyces dairenensis, an unconventional yeast that ferments only reducing sugars and leaves sucrose untouched. A laboratory-scale test using sugarcane juices with a high composition of reducing sugars (100 g kg−1) resulted in a sucrose crystal yield increase from a single extraction, from 16.2 to 65.1%, by introducing selective fermentation. The second extraction, from the molasses, which was enabled by the lowered residual reducing sugar composition, further enhanced the total sugar crystal yield (up to 83.4%). A simulation of the application of this technology in the U.S.A. revealed that both sugar and ethanol production were enhanced, whereas sugar production declined by the mere adoption of high yield cultivar, even with the increase in sugarcane yield. [Copyright &y& Elsevier]

Abstract: Thin-walled carbon nanotubes (TWCNTs) were synthesized using a zirconium (Zr) plate by cold-wall chemical vapor deposition of a mixture gas consisting of C2H2 and H2 under a pressure of 1.20torr. The Zr plate was used for the formation of Zr nanocatalysts during the thermal process and used as substrate to eliminate the effects of interactions between catalyst and substrate during CNT synthesis. The TWCNTs were 4–9nm in diameter and a few micrometers long. Nanometer-sized defects on the Zr bulk material may have a low melting temperature, allowing them to form droplet-like catalysts and achieve high carbon solubility for the formation of CNTs. [Copyright &y& Elsevier]

Abstract: Iron-containing adsorbents prepared from methane fermentation sludge (MFS) were characterized by N2 adsorption, XRD, SEM, EDX, pH determination and elemental analysis. The experiments for copper removal from aqueous solution using the MFS-derived adsorbents were performed, and the effects of iron content, forms of the iron (hydr)oxides, surface basicity and pH of the aqueous solution on copper removal were elucidated respectively. The desorption studies were also performed and the mechanism of Cu(II) adsorption was proposed. The results indicated that the adsorbent obtained at 700°C for 1h in a steam atmosphere possessed the highest capability for Cu(II) adsorption. The high copper removal ability of the MFS-derived materials is attributed to their intermediate surface area, strong surface basicity and the presence of iron (hydr)oxides on their surface. The Cu(II) adsorption onto the composite adsorbents is via ion-exchange with H, Ca and K ions, surface precipitation and binding with active sites on the surface of iron (hydr)oxides at various pH values. The desorption of copper in deionized water is quite low. The irreversibility of copper adsorption on the iron-containing adsorbents is attributed to the formation of strong bonds between Cu(II) and the iron (hydr)oxides. The adsorbent can be applied to remove copper from water or soil by fixation onto the surface. [Copyright &y& Elsevier]

Abstract: The activated carbons (ACs) prepared from cattle manure compost (CMC) with various pore structure and surface chemistry were used to remove phenol and methylene blue (MB) from aqueous solutions. The adsorption equilibrium and kinetics of two organic contaminants onto the ACs were investigated and the schematic models for the adsorptive processes were proposed. The result shows that the removal of functional groups from ACs surface leads to decreasing both rate constants for phenol and MB adsorption. It also causes the decrement of MB adsorption capacity. However, the decrease of surface functional groups was found to result in the increase of phenol adsorption capacity. In our schematic model for adsorptive processes, the presence of acidic functional groups on the surface of carbon is assumed to act as channels for diffusion of adsorbate molecules onto small pores, therefore, promotes the adsorption rate of both phenol and MB. In phenol solution, water molecules firstly adsorb on surface oxygen groups by H-bonding and subsequently form water clusters, which cause partial blockage of the micropores, deduce electrons from the π-electron system of the carbon basal planes, hence, impede or prevent phenol adsorption. On the contrary, in MB solution, the oxygen groups prefer to combine with MB+ cations than water molecules, which lead to the increase of MB adsorption capacity. [Copyright &y& Elsevier]

Abstract: In recent years, the exploration and development of the effective methods of treatment and prevention to algal blooms, especially Microcystis aeruginosa blooms has been an important issue in the field of water environment protection. Allelochemicals (natural plant toxins) are considered promising sources of algicides to control algal blooms. The objective of this study is to determine the inhibitory effects and potential mechanisms of a well-known allelochemical gramine (N,N-dimethyl-3-amino-methylindole) on bloom-forming cyanobacterium M. aeruginosa. The results showed that this indole alkaloid effectively inhibited the growth of M. aeruginosa. The effective concentration causing a 50% inhibition at 3 d (EC50, 3 d) increased with the initial algal density (IAD) increasing. When IAD increased from 5×104 to 5×105 cellsmL−1, the values of EC50, 3 d increased from 0.5 to 2.1mgL−1. In the cells of M. aeruginosa, gramine caused an obvious increase in the level of reactive oxygen species (ROS). The lipid-peroxidation product malondialdehyde (MDA) increased significantly in gramine-treated cells. The effects of gramine on enzymatic and non-enzymatic antioxidants were in different manners. The activity of superoxide dismutase (SOD) was decreased after gramine exposure. The catalase (CAT) activity was increased after 4h but decreased from 60h. Both the contents and the regeneration rates of ascorbic acid (AsA) and reduced glutathione (GSH) were increased after 4h of exposure to gramine. However, only GSH content was still increased after 40h of exposure. These results suggested that the activation of antioxidants in M. aeruginosa played an important role to resist the stress from gramine at initial time, the inactivation of SOD is crucial to the growth inhibition of M. aeruginosa by gramine, and the phytotoxicity of gramine on M. aeruginosa may be due to oxidative damage via oxidation of ROS. [Copyright &y& Elsevier]

Abstract: The separation of valuable chemicals from raw products, where a great number of chemicals coexist, is the key technology in biomass refinery. In this study, the applicability of membrane separation of valuable chemicals from our currently developed portable superheated steam (SHS) biomass pyrolysis process was demonstrated. Phenols (phenol, p-cresol, guaiacol, methyl guaiacol, and ethyl guaiacol), furfural, and acetone were successfully separated by pervaporation using the silicone rubber membrane from model solutions and an actual SHS derived aqueous solution. The solution was also concentrated effectively by reverse osmosis separation using a polyamide membrane. When a high concentration of SHS solution was fed to the pervaporation process, a phase-separated permeate was obtained, which indicated that the reverse osmosis concentration combined with pervaporation separation is useful for the superheated steam process. [Copyright &y& Elsevier]

Abstract: To develop a novel noncatalytic biomass refinery process that can be used as a portable process, superheated steam pyrolysis was investigated to produce both carbonized solid fuels and chemicals using a large-scale reactor. Individual biomass components and native biomass (Sugi, Japanese cedar) were pyrolyzed. Between 150 and 400°C, the vaporizing fractions of cellulose, xylan, and kraft lignin were summarized using a numerical model. Cellulose was converted to glycolaldehyde, furfural, 5-hydroxymethyl furfural and levoglucosan, whereas xylan was converted to glycolaldehyde, furfural, and acetic acid. Kraft lignin produced a slight yield of phenol and guaiacol. The total vaporization fraction of Sugi and its vaporizing rate were explained sufficiently using a numerical model based on the weighted average of the vaporizing properties of the individual components. However, the yields of phenol, guaiacol, and acetic acid were underestimated, while the yields of furfurals and levoglucosan were overestimated. Possible synergetic effects among chemicals in the superheated steam pyrolysis of native biomass were also discussed. [Copyright &y& Elsevier]

Abstract: This paper presents an application of our newly developed adsorptive ozonation process using a high silica zeolite adsorbent (USY) for drinking water treatment. First, the adsorption of 2-methylisoborneol (2-MIB) on USY in a river water/pure water mixture was clarified by a batch-type adsorption experiment. The results showed that 2-MIB was adsorbed on USY; however, almost all of the adsorbed 2-MIB was desorbed over time. The desorption rate was increased with the ratio of river water to pure water, indicating that compounds dissolved in the river water, such as natural organic matter (NOM), prevent the adsorption of 2-MIB on USY. Second, the ability of the river water to consume ozone was confirmed in an experiment using a USY-packed column reactor. The ozone consumption was obviously increased by the presence of USY, indicating that USY-adsorbing compounds dissolved in the river water (probably small size NOM) consumed the ozone. However, the rapid ozone consumption was occurred by 6–8s in the retention times when 3.14–4.38mgL−1 of water dissolved ozone was fed, this rapid ozone consumption lasted no more than these times. This result revealed that the rapid consumption of ozone by the adsorptive compounds in our process could be avoided within a certain retention time (6–8s; especially for the river water used in this study) when enough concentration of ozone (3.14mgL−1 or more; same above) was supplied. We therefore performed a trial in which 2-MIB dissolved in river water was continuously decomposed using a USY-packed column with various ozone concentrations. In the process, the adsorptive compound dissolved in the river water adsorbed and reacted with ozone in the parts of the apparatus upstream of the column, while the adsorption and decomposition of 2-MIB took place in the parts of the apparatus downstream of the column. This resulted in a sufficient 2-MIB decomposition with minimizing bromate ion formation. [Copyright &y& Elsevier]

Abstract: This work elucidates the applicability of our newly developed adsorptive ozonation process for the decomposition of 2-methylisoborneol (MIB), a typical taste and odor chemical, without the formation of possibly carcinogenic bromate ions. First, zeolite adsorbents were screened for their ability to adsorb MIB with a batch-type adsorption experimental apparatus and a flow-type decomposition experimental apparatus included an adsorbent-packed column. The USY zeolite with the highest silica to alumina ratio (SiO2/Al2O3 molar ratio=70) showed the best performance as an adsorbent. Using this adsorbent, an ozonation experiment on an MIB solution including bromide ions was performed under various retention times using the flow-type apparatus. As a result, sufficient decomposition of MIB was achieved with preventing bromate formation. [Copyright &y& Elsevier]

Abstract: Simple evaluation of toxicity of suspended particulate matter (SPM) in humans is strongly required. The in vivo mimicking exposure of actual SPM samples to human lung alveolar epithelia was achieved using an air–liquid interface culture (ALIC) of human lung alveolar A549 cells, resulting in successful observation of the toxicity in terms of the cell survivability after 48h exposure. Although in the cytotoxicity tests in terms of cell survivability, neither the A549 nor hepatocarcinoma (Hep G2) cell failed to detect toxicity in the usual liquid phase, an ethoxyresorufin O-deethylase (EROD)-capacity-based assay of the Hep G2 cell was used to successfully observe biological responses against the SPM extracts. Therefore, an integrated use of the ALIC-based A549 cell assay for general toxicity and the EROD-based Hep G2 cell assay for PAHs is recommended to evaluate the primary toxicity of SPM. We further attempted to understand the permeation kinetics of SPM toxicity across the alveolar epithelia in terms of the EROD capacity of Hep G2 cells, and were able to obtain basic information on SPM toxicity in humans, such as direct toxicity to alveolar epithelia and indirect potential toxicity to other organs. In summary, we concluded that these integrated uses for evaluating SPM toxicity are promising as a novel bioassay method. [Copyright &y& Elsevier]

We developed a novel ozonation process for water treatment using high silica zeolites as an adsorptive concentrator of water-dissolved ozone and organic pollutants, resulting in a significant increase in reaction rate. In experiments involving trichloroethene (TCE) decomposition using a tubular flow reactor, TCE decomposition was much greater in the presence of ZSM-5 (SiO2/Al2O3 ratio=3000) than in its absence, possibly due to the high concentrations of ozone and TCE inside the adsorbent. The TCE conversion obtained in our experiments was found to reach its theoretically maximum limit. [Copyright &y& Elsevier]

The adsorption properties of water-dissolved ozone on high silica zeolites were investigated. Adsorbed ozone was desorbed almost reversibly. The adsorption equilibrium relations were described by a linear expression written as q=βC, where q is the amount adsorbed, C is the equilibrium concentration and β is the equilibrium constant. Also, the β values were strongly dependent on the SiO2/Al2O3 ratio (mol/mol) and on the pore structure of the high silica zeolites. The larger the SiO2/Al2O3 ratio, the larger the value of β. ZSM-5 (SiO2/Al2O3 ratio: 3000), which gave the highest adsorption capacity of water-dissolved ozone, was able to highly concentrate water-dissolved ozone on the adsorbent. The decomposition behavior of adsorbed ozone was also investigated. Ozone adsorbed on high silica zeolite was observed to be a little more stable than ozone existing in bulk water. The decomposition rate was independent of SiO2/Al2O3 ratios in the range of 30–3000 or a solution pH in the range of 4–6. [Copyright &y& Elsevier]