Removal of Borate Ions from Wastewater Using an Adsorbent Prepared from Waste Concrete (PAdeCS).

The removal of boron from model wastewater using PAdeCS, a material derived from waste concrete, was studied. Three different types of boron removal methods were examined: adsorption with untreated PAdeCS, adsorption with heat-treated ettringite-enriched PAdeCS, and coagulation-sedimentation method by mixing untreated PAdeCS as a calcium source and aluminum sulfate as an aluminum and sulfate ion source for the formation of ettringite. The highest boron removal performance was observed for the coagulation-sedimentation method, where the boron concentration in the model wastewater decreased rapidly from 100 mg/L to the level below the Japanese effluent standard at 10 mg/L when the weight ratio of PAdeCS addition into water is 4.0% with aluminum sulfate, of which the added amount corresponds to the stoichiometric condition for the formation of ettringite (Ca:Al:SO4 2- = 6:2:3). The heat-treated ettringite-enriched PAdeCS also showed higher boron removal performances compared with untreated PAdeCS. The dependency of the boron removal capacity on the aqueous boron concentration can be expressed by the Langmuir equation for all the cases. The maximum capacity (q m) values were 1.83, 3.39, and 3.02 mg/g-solid for adsorption with untreated PAdeCS, adsorption with heat-treated ettringite-enriched PAdeCS, and coagulation-sedimentation, respectively. These capacities were higher or comparable with the ones reported in the literature.

Preparation of High-Purity Calcium Carbonate by Mineral Carbonation Using Concrete Sludge.

A new type of mineral carbonation process for concrete sludge, a waste of fresh concrete under hydration, was developed, and the carbonation performances of the process were examined by laboratory-scale experiments. The process is composed of two steps; filtration of concrete sludge and bubbling of CO2 into the filtrate to form calcium carbonate. Model concrete sludge, a mixture of cement and water, was filtered through a cellulose filter after hydration for 24 h to obtain a solution containing dissolved calcium ions. Then, the model flue gas containing CO2 (10%) was bubbled through the filtrate solution, and calcium carbonate was precipitated by the carbonation reaction. About 3% of calcium in the concrete sludge could be extracted into the filtrate in a single filtration step, and more than 95% of dissolved calcium was recovered as calcium carbonate by the bubbling of CO2. The obtained calcium carbonate was calcite with a high purity (>95%) and 5-10 µm. The solid residue (concrete sludge) after filtration was mixed with fresh water and filtered through a cellulose filter. Then, the model flue gas was bubbled into the filtrate solution for carbonation. This filtration-bubbling step was repeated 5 times, and 10.8% of calcium in the feed cement was extracted into the filtrates in total. More than 95% of the extracted calcium could be recovered as calcium carbonate with high purity (>97%), and the overall conversion of calcium in the feed cement to calcium carbonate was 10.1%. The purity of calcium carbonate and the calcium conversion were much higher than those for the direct bubbling method, where the model flue gas is bubbled into concrete sludge.

Removal of fluoride ions from aqueous solution by metaettringite.

Fluoride contamination is a major problem in wastewater treatment. Metaettringite (which has previously shown enhanced anion adsorption) was investigated as a possible adsorbent to remove fluoride from low-concentration solution (25 mg-F/L). The fluoride removal properties of ettringite and metaettringite were first compared at pH 10, and metaettringite was found to be more effective. The dominant reaction mechanism for fluoride adsorption in metaettringite was found to be recrystallization of metaettringite by rehydration; this was accompanied by precipitation of calcium fluoride. The adsorption kinetics followed the pseudo-second order model. Metaettringite was also able to remove fluoride effectively in low pH environment (i.e., at pH 3.5). The influence of coexistence of sulfate ions in solution on the fluoride removal performance was investigated, and a small decrease in performance was noted. The residual fluoride concentrations obtained with higher doses of metaettringite were lower than those specified by the Japanese effluent standard (non-coastal areas: 8 mg-F/L; coastal areas: 15 mg-F/L). The fluoride removal capacity of metaettringite was compared with those of other solid materials. The observed maximum capacity was 174.7 mg-F/g-metaettringite. In the case of high fluoride concentration solution, the main removal mechanism will be changed to calcium fluoride precipitation. In general, metaettringite is regarded as promising material for fluoride removal in wastewater treatment.

Investigation of Mineral Carbonation with Direct Bubbling into Concrete Sludge.

Mineral carbonation, which is CO2 fixation through a carbonation reaction using alkaline earth metals, is being investigated as a carbon capture and utilization method to reduce CO2 atmospheric emissions. Concrete sludge is an alkali waste material from the concrete industry and contains abundant calcium components. We investigated the applicability of concrete sludge for mineral carbonation. In this study, gas containing CO2 was bubbled through the model concrete sludge solution and the effects of the solid-liquid ratio, bubbling time, gas flow rate, and the partial pressure of CO2 on the CO2 fixation ratio and fixation rate were investigated. The CO2 fixation ratio decreased with increasing CO2 bubbling time, CO2 flow rate, and CO2 partial pressure. The CO2 fixation rate increased with increasing CO2 flow rate and CO2 partial pressure. The formation of calcite, a form of calcium carbonate, was confirmed.

Emission fluxes of styrene monomers and other chemicals for products containing expanded polystyrene beads.

Styrene in indoor air can adversely affect human health. In this study, styrene monomer and other chemical emission fluxes for products containing expanded polystyrene beads (pillows, cushions, and soft toys) were measured at various temperatures to simulate typical product use. The contributions of the products to styrene and other chemical concentrations in indoor air and human exposure to these chemicals were estimated, and health risk assessments were performed. The styrene monomer emission fluxes for the samples at 25°C were between 25.3 and 8.73×103 µg/(m2 h). The styrene emission fluxes for the product surfaces increased strongly as the temperature increased, from between 124 and 2.44×104 µg/(m2 h) at 36°C (simulating human body temperature) to between 474 and 4.59×104 µg/(m2 h) at 50°C (simulating inside an automobile in summer). The hexane, heptane, toluene, octane, ethylbenzene, m- and p-xylene, o-xylene, and dodecane emission fluxes at 25°C for the sample that emitted the analytes most readily were high. The maximum estimated styrene and xylene concentrations in indoor air caused by emissions from expanded polystyrene beads at 36°C in a bedroom and automobile were higher than the relevant guidelines. The maximum contribution of a product containing expanded polystyrene beads in a living room, bedroom, or automobile could cause the total volatile organic compound concentration in air to exceed the advisable value (400 µg/m3). The estimated maximum hazard quotients for styrene, toluene, and xylene emitted by a product containing expanded polystyrene beads at 36°C in a bedroom were 0.59, 0.30, and 0.37, respectively. These non-carcinogenic risk values for single products could contribute to the non-carcinogenic risk thresholds being exceeded when multiple products and other sources of chemicals are taken into consideration. The estimated styrene concentrations suggest that products containing expanded polystyrene beads are important sources of styrene to indoor air.

Volatile and semivolatile organic compound emissions from polymers used in commercial products during thermal degradation.

Emissions of volatile and semivolatile organic compounds from various kinds of polymer sheets during thermal degradation process were determined by the passive flux sampling method. The polymer sheets used were commercial products made of: polyethylene (PE), ethylene-vinyl acetate (EVA), polypropylene (PP), polyacetal (POM), polycarbonate (PC)), and polymer sheet samples: poly (methyl methacrylate) (PMMA), polyethylene terephthalate (PET), polystyrene (PS) and four types of poly vinyl chloride (PVC) with different contents of additives; (bis(2-ethylhexyl)phthalate (DEHP)), and triphenylphosphine (TPP)). The emission fluxes from the polymer sheets were measured for up to 30 days stored under a constant temperature (25-75 °C). Emission of various kinds of chemicals were observed from PVC sheets including and products of polymer degradation, while emission of hydrocarbons were dominant from PE, PP and EVA, and the emission of an additive (DEP) only was observed from PMMA, PET, POM and PC. The TVOC (total VOC) emission rates from PVC sheets with DEHP and TPP (soft PVCs) were in the range of 30-120 mg m-2 h-1 at 50 °C, which were much higher than the TVOC emission rates from other polymers. The emission rates for these chemicals for the same sampling period increased dramatically as the temperature increased. The temperature-dependences of the emission rates from the soft PVC sheet for a given sampling period could be expressed using an Arrhenius-type equation, and the apparent emission activation energy E A , correlated well with the enthalpy of vaporization ΔH VAP by the following empirical equation. E A = 2.27 Δ H vap - 115 We also found that the emission rates of chemicals changed with time with different changing characters, and the activation energy decreased with the progress of the polymer degradation.

Recombinant human soluble thrombomodulin ameliorates acetaminophen-induced liver toxicity in mice.

Recombinant human soluble thrombomodulin alpha (rhTM) has been developed as an anticoagulant with anti-inflammatory activity. Notably, acetaminophen (APAP) -induced liver disease (AILI) is caused by direct metabolite-induced hepatotoxicity as well as hepatic hyper-coagulation. To evaluate the utility of anticoagulant for the treatment of AILI, rhTM was administered in a mouse AILI model and liver damage was analyzed. AILI was induced in 8-week-old mice by intraperitoneal injection of APAP. rhTM (20 mg/kg) or placebo was injected at the same time as APAP administration. Serum alanine aminotransferase, fibrin degradation products and high-mobility group box 1 levels were significantly decreased in the rhTM-treated group compared with the control group. Furthermore, rhTM reduced the necrotic area and fibrin deposition in liver sections. rhTM suppressed the mRNA expression of heme oxygenase-1, plasminogen activator inhibitor type-1, tissue factors, and inflammatory cytokines compared with the control group. rhTM did not change the hepatic GSH content at 2 h after APAP injection, but restored them at 4 h after the insult. rhTM ameliorated liver damage in mice with AILI, probably via the improvement in liver perfusion induced by it's anticoagulant acitivity, which can lead to the suppression of secondary liver damage.

Effects of high fructose intake on liver injury progression in high fat diet induced fatty liver disease in ovariectomized female mice.

Epidemiology shows that the morbidity of nonalcoholic fatty liver disease (NAFLD) is increased in postmenopausal women and chronic high fructose intake induces NAFLD progression. To analyze the effects of high fructose intake on estrogen deficiency, we evaluated liver disease progression using ovariectomized mice fed with a high fat diet (HFD) for 12 weeks. Hepatic steatosis developed in all HFD groups. Fructose intake significantly increased the liver weight and serum alanine aminotransferase, which was not exacerbated by ovariectomy alone. Ovariectomy enhanced the hepatic inflammatory activity shown by tumor necrosis factor α upregulation in the groups with or without fructose intake. Both fructose intake and ovariectomy increased the hepatocytes with ballooning degeneration and hepatic macrophage infiltration and activated hepatic stellate cells. Coexistence of fructose intake and ovariectomy markedly enhanced liver cell destruction, macrophage accumulation, and progression of fibrosis. Liver damage was ameliorated by 17ß-estradiol supplementation. These findings suggest that high fructose intake enhanced the progression of NAFLD in ovariectomized female mice.

Correlation between Odor Concentration and Volatile Organic Compounds (VOC) Composition of Environmental Tobacco Smoke (ETS).

We examined the correlation between the odor concentration and the chemical composition of environmental tobacco smoke (ETS). Three types of ETS samples were prepared: secondhand smoke (SHS), thirdhand smoke (THS), and field ETS samples from an outside smoking area. The odor concentrations of the ETS, SHS, and THS samples were determined by the triangle-odor-bag method, and the chemical compositions were determined by proton transfer mass spectrometry. The odor concentration of the SHS samples was three or four orders of magnitude higher than that of the field ETS samples, and three orders of magnitude higher than that of the THS samples. The concentration ratios of the constituent chemicals in THS to those in SHS were about 10-4, corresponding to the ratio of the odor concentration. The concentration ratios of the constituent chemicals in the field ETS samples were much lower than the ratios of the odor concentrations. This suggests that the main contributing components to the odor of the field ETS samples are different from those in SHS and THS. The main contributors of the odor in the field ETS samples could be acetaldehyde, acetonitrile, acetic acid, and other unknown components with a mass-to-charge ratio (m/z) of 39 and 43.

Measurements of Volatile Organic Compounds in a Newly Built Daycare Center.

We measured temporal changes in concentrations of total volatile organic compounds (TVOCs) and individual volatile organic compounds in a newly built daycare center. The temporal changes of the TVOC concentrations were monitored with a photo ionization detector (PID), and indoor air was sampled and analyzed by Gas Chromatography/Mass Spectrometry (GC/MS) and high performance liquid chromatography (HPLC) to determine the concentrations of the constituent VOCs. The measurements were performed just after completion of the building and again 3 months after completion. The TVOC concentration exceeded 1000 µg·m(-3) for all the sampling locations just after completion of building, and decreased almost one tenth after 3 months, to below the guideline values of the TVOC in Japan at 400 µg·m(-3). The concentrations of the target VOCs of which the indoor concentrations are regulated in Japan were below the guideline values for all the cases. The air-exchange rates were determined based on the temporal changes of the TVOC concentrations, and it was found that the countermeasure to increase the air exchange rate successfully decrease the TVOC concentration level in the rooms.

Deteriorated portal flow may cause liver failure in patients with hepatocellular carcinoma being treated with sorafenib.

We encountered two patients with hepatocellular carcinoma (HCC) who showed rapid progression of liver failure during sorafenib treatment. One had portal vein tumor thrombus (PVTT) and the other developed portal vein thrombosis (PVT) during the treatment, and both of them experienced the elevation of serum lactate dehydrogenase (LDH) concentration during the administration of sorafenib. Their clinical courses indicate that the liver failure might have been caused by sorafenib-induced liver hypoxia, being amplified in the circumstances with reduced portal flow. To our best knowledge, all the reported patients who achieved complete remission (CR) during sorafenib monotherapy had a condition that could decrease portal blood flow. We hypothesized that pathogenesis of disease may be similar in HCC patients who achieve CR and those who experience liver failure while on sorafenib. Sorafenib treatment of patients with HCC and deteriorated portal flow may be a double-edged sword.

Optimized arrangement of constant ambient air monitoring stations in the Kanto region of Japan.

Continuous ambient air monitoring systems have been introduced worldwide. However, such monitoring forces autonomous communities to bear a significant financial burden. Thus, it is important to identify pollutant-monitoring stations that are less efficient, while minimizing loss of data quality and mitigating effects on the determination of spatiotemporal trends of pollutants. This study describes a procedure for optimizing a constant ambient air monitoring system in the Kanto region of Japan. Constant ambient air monitoring stations in the area were topologically classified into four groups by cluster analysis and principle component analysis. Then, air pollution characteristics in each area were reviewed using concentration contour maps and average pollution concentrations. We then introduced three simple criteria to reduce the number of monitoring stations: (1) retain the monitoring station if there were similarities between its data and average data of the group to which it belongs; (2) retain the station if its data showed higher concentrations; and (3) retain the station if the monitored concentration levels had an increasing trend. With this procedure, the total number of air monitoring stations in suburban and urban areas was reduced by 36.5%. The introduction of three new types of monitoring stations is proposed, namely, mobile, for local non-methane hydrocarbon pollution, and Ox-prioritized.

A cluster analysis of constant ambient air monitoring data from the Kanto region of Japan.

This study demonstrates an application of cluster analysis to constant ambient air monitoring data of four pollutants in the Kanto region: NOx, photochemical oxidant (Ox), suspended particulate matter, and non-methane hydrocarbons. Constant ambient air monitoring can provide important information about the surrounding atmospheric pollution. However, at the same time, ambient air monitoring can place a significant financial burden on some autonomous communities. Thus, it has been necessary to reduce both the number of monitoring stations and the number of chemicals monitored. To achieve this, it is necessary to identify those monitoring stations and pollutants that are least significant, while minimizing the loss of data quality and mitigating the effects on the determination of any spatial and temporal trends of the pollutants. Through employing cluster analysis, it was established that the ambient monitoring stations in the Kanto region could be clustered topologically for NOx and Ox into eight groups. From the results of this analysis, it was possible to identify the similarities in site characteristics and pollutant behaviors.

Preparation and performance of arsenate (V) adsorbents derived from concrete wastes.

Solid adsorbent materials, prepared from waste cement powder and concrete sludge were assessed for removal of arsenic in the form of arsenic (As(V)) from water. All the materials exhibited arsenic removal capacity when added to distilled water containing 10-700 mg/L arsenic. The arsenic removal isotherms were expressed by the Langmuir type equations, and the highest removal capacity was observed for the adsorbent prepared from concrete sludge with heat treatment at 105°C, the maximum removal capacity being 175 mg-As(V)/g. Based on changes in arsenic and calcium ion concentrations, and solution pH, the removal mechanism for arsenic was considered to involve the precipitation of calcium arsenate, Ca3(AsO4)2. The enhanced removal of arsenic for the adsorbent prepared from concrete sludge with heat treatment was thought to reflect ion exchange by ettringite. The prepared adsorbents, derived from waste cement and concrete using simple procedures, may offer a cost effective approach for arsenic removal and clean-up of contaminated waters, especially in developing countries.

Hepatocarcinogenesis in chronic hepatitis C patients achieving a sustained virological response to interferon: significance of lifelong periodic cancer screening for improving outcomes.

BACKGROUND: Due to advances in interferon (IFN) therapy for chronic hepatitis C, most elderly patients, and even many of those with advanced hepatic fibrosis, now achieve a sustained virological response (SVR). However, carcinogenesis remains problematic in these patients. Hence, we aimed to elucidate risk factors for hepatocarcinogenesis in SVR patients and to present an appropriate follow-up protocol for improving outcomes. METHODS: We retrospectively studied 562 consecutive SVR patients for a median observation period of 4.8 years. RESULTS: Hepatocellular carcinoma was diagnosed in 31 patients (5.5%). Respective cumulative incidences were 3.1, 10.1, and 15.9% at 5, 10, and 15 years after completion of IFN therapy. The proportional hazards model identified moderate or advanced fibrosis stage, advanced age, habitual alcohol consumption, and alpha-fetoprotein elevation as determinants of carcinogenesis, with hazard ratios of 10.7 (p < 0.001), 4.1 (p < 0.01), 3.9 (p < 0.01), and 2.6 (p < 0.05), respectively. Carcinoma was diagnosed in 26% of patients more than 10 years after completion of IFN therapy. Unexpectedly, F2 fibrosis was detected in 42% of these patients. The 5-year survival rate was 93% in the patients who had received periodic cancer screening but only 60% in those who had not. CONCLUSION: We recommend that SVR patients be observed at 6-month intervals, at a minimum, to facilitate diagnosis at an early stage, for as long as possible after completion of therapy even if not at an advanced stage of fibrosis.

Development of a combined real time monitoring and integration analysis system for volatile organic compounds (VOCs).

A combined integration analysis and real time monitoring (Peak Capture System) system was developed for volatile organic compounds (VOCs). Individual integration analysis and real time monitoring can be used to qualitatively and quantitatively analyze VOCs in the atmosphere and in indoor environments and determine the variation in total VOC (TVOC) concentration with time, respectively. In the Peak Capture System, real time monitoring was used to predict future elevations in the TVOC concentration (peak), and this was used an indicator of when to collect (capture) ambient air samples for integration analysis. This enabled qualitative and quantitative analysis of VOCs when the TVOC concentration was high. We developed an algorithm to predict variation in the TVOC concentration, and constructed an automatic system to initiate air sampling for integration analysis. With the system, auto-sampling and analysis of VOCs in a conventional house were conducted. In comparison with background concentrations, the results of peak analysis enabled identification of compounds whose concentration rose. This also enabled an evaluation of possible VOC emission sources.

A new method using a health index (HI) to screen low level toxic organic substances in consumer products.

To ensure selection of appropriate materials for industrial use in terms of toxicity, a procedure to estimate a health index (HI) that can be used for prioritizing less hazardous components of consumer products is described. The HI is based on the occupational exposure limits (OELs) of organic substances that compose the products. To calculate the HI of a product, it is often necessary to predict OEL values for the substances for which an OEL value has not yet been promulgated. We developed a method to estimate the OEL values from median lethal dose (LD50) data of rodent. A good correlation between known OEL values and the LD50 data was obtained by a multivariate regression analysis by introducing organic compensation coefficients, which were caluculated as 10 to the Bth power where B is the regression coefficient of dummy variables denoting the characteristics of the organic compounds such as functional groups, molecular structures, and so on. We believe that the use of the present method should be limited to predicting unknown OEL values for the HI and used for material prioritization. It should not be extended to determinations of regulatory OELs.

Methodology for predicting OEL from rodent LD50 values for metals and metallic compounds.

The relationship between the occupational exposure limits (OEL) and the lethal dose 50 (LD50) values of rats or mice for metals and metallic compounds was statistically analyzed by a stepwise multivariate regression method. The OEL values were predicted from LD50 values and metallic compensation coefficients (MCC), which were developed as the regression coefficients of dummy variables that represented the metallic element contained in the substance of interest. The value of the MCC indicated the extent of the adverse health effects of the metal in the substance. Smaller values of the MCC were assigned to metals that would have the more severe adverse health effects, such as carcinogenesis, while larger values were given to the less toxic metals. The Health Index (HI) based on the OEL values was proposed as a convenient measure of the toxicity of industrial products. The prediction method could be applied to toxicity risk assessments by using the HI when a designer of consumer products wants to use substances for which OEL values have not been determined. Two case studies were conducted to estimate the potential toxicity of materials used in solders and in rechargeable batteries.

A new method for separating HFC-134a from gas mixtures using clathrate hydrate formation.

A new separation method using gas hydrate formation is proposed for separating HFC-134a from gas mixtures containing N2 and HFC-134a. The feasibility of this separation method was investigated from various points of view. First, to determine the mixed hydrate stability region, three-phase equilibria of hydrate (H), liquid water (Lw), and vapor (V) for HFC-134a + N2 + water mixtures with various HFC-134a vapor compositions were closely examined in the temperature and pressure ranges of 275-285 K and 0.1-2.7 MPa, respectively. Second, the compositions of the hydrate and vapor phases at a three-phase equilibrium state were analyzed for identical mixtures at 278.15 and 282.15 K to confirm the actual separation efficiency. Third, kinetic experiments were performed to monitor the composition change behavior of the vapor phase and to determine the time required for an equilibrium state to be reached. Furthermore, X-ray diffraction confirmed that the mixed HFC-134a + N2 hydrates were structure II. Through an overall investigation of the experimental results, it was verified that more than 99 mol % HFC-134a could be obtained from gas mixtures after hydrate formation and subsequent dissociation processes. Separation of HFC-134a using hydrate formation can be carried out at mild temperature and low-pressure ranges. No additive is needed to lower the hydrate formation pressure.

Field validation of an active sampling cartridge as a passive sampler for long-term carbonyl monitoring.

A carbonyl sampler originally designed for the active sampling method (Sep-Pak XPoSure) was used for long-term passive sampling, and its applicability as a passive sampler was examined through field experiments. The uptake rates of passive sampling were determined experimentally from collocated passive and active samplings for various sampling periods. The obtained uptake rates of formaldehyde, acetaldehyde, and acetone were 1.48, 1.23, and 1.08 mL/min, respectively. These uptake rates were consistent for a wide range of the sampling term (12 hr-2 weeks). Uptake rates of each carbonyl were proportional to the diffusion coefficients of each. Therefore, the ratios of diffusion coefficients were used to calculate the uptake rates of carbonyls for which the rates were not determined experimentally. Lower limits of determination were 2.16-17.5 microg/m3 for 2-week sampling. It was confirmed that 2-week monitoring of carbonyl concentrations up to 118-229 microg/m3 was possible. Relative standard deviations of the passive method generated from the repeatability test were 2-12.3% error for five samplings, and the recovery efficiencies were larger than 90%. Thus, the passive sampler was found to be highly suitable for long-term monitoring of carbonyl compounds.