Preparation and characteristics of high performance paper containing titanium dioxide photocatalyst supported on inorganic fiber matrix

A novel paper-based material containing titanium dioxide (TiO₂) photocatalyst was successfully prepared by a papermaking technique with the internal addition of inorganic fibers on which TiO₂ particles were supported. Photodegradation performance of acetaldehyde gas, an indoor pollutant, and the durability of the TiO₂-containing papers were investigated under UV irradiation. Ceramic fiber suspension and polydiallyldimethylammonium chloride as a cationic flocculant were mixed, followed by the addition of TiO₂ suspension and anionic polyacrylamide. Subsequently, the inorganic mixture was poured into a pulp suspension, and TiO₂ handsheets then prepared by a papermaking method. The tensile strength of TiO₂-containing paper without a ceramic carrier decreased by more than 30% after 240-h UV irradiation (2 mW/cm²), although the strength of the TiO₂ sheet with ceramic fibers remained reasonably stable. The efficiency of acetaldehyde decomposition by the TiO₂ paper containing an inorganic carrier was nearly equal to that of the carrier-free TiO₂ paper. Scanning electron microscopic observation suggested that most TiO₂ particles were predominantly supported on the inorganic fiber matrix, and were mostly out of contact with organic pulp fibers. The TiO₂ paper with an inorganic carrier demonstrated both excellent photocatalytic performance and durability, which before had been mutually incompatible for organic materials containing TiO₂ photocatalyst. The two-stage mixing procedure for TiO₂ sheet-making is promising for the simple manufacture of high performance paper with photocatalytic ability.     

Long Range Transport of Asian Dust from Dust Storms and its Impact on Japan

We simulated the long range transport of dust emitted from dust storms that occurred in China by using a global three-dimensional chemical transport model. A modified dust emission flux scheme and a nonlocal diffusion scheme for determining the atmospheric eddy diffusivity in the atmospheric boundary layer were implemented to improve the chemical transport model. We examined the dust transport by comparing the model results with TOMS satellite images. The model calculated monthly total deposition of dust masses were used for comparison with the measurements collected at sampling stations in Japan, and good agreement was found. The model generally reproduced the temporal and spatial variations of dust reasonably well.     

长良川水质中溶解氧和化学耗氧量预测模型的建立

文章介绍了GMDH(group method of data handling)方法的基本运算法则，运用改进后的GMDH方法，建立长良川溶解氧和化学耗氧量两个水质项目的长期预到模型，模型相关度可达0．96，基本满足要求，并根据模型对水质变化机理进行分析。     

Assessing the economic value of urban green spaces in Kuala Lumpur

Environmental Science and Pollution Research - This study assessed the economic value of public urban green spaces (UGSs) in Kuala Lumpur (KL) city by using the hedonic price method (HPM). It...     

How seasonality affects the flow of estrogens and their conjugates in one of Japan's most populous catchments

A detailed study of the free and conjugated estrogen load discharged by the eight major sewage treatment plants into the Yodo River basin, Japan was carried out. Sampling campaigns were focused on the winter and autumn seasons from 2005 to 2008 and the free estrogens estrone(E1), 17β-estradiol(E2), estriol(E3), 17α-ethynylestradiol(EE2) as well as their conjugated (sulfate and glucuronide) forms. For both sewage effluent and river water E2 and E1 concentrations were greatest during the winter period (December-March). This coincides with the period of lowest rainfall and lowest temperatures in Japan. E1 was the dominant estrogenic component in effluent (means of 10-50 ng/L) followed by E2 (means of 0.5-3 ng/L). The estrogen sulfate conjugates were found intermittently in the 0.5-1.7 ng/L concentration range in the sewage effluents. The greatest estrogen exposure was found to be in the Katsura River tributary which exceeded 1 ng/L E2-equivalents during the winter period.     

Woody biomass and RPF gasification using reforming catalyst and calcium oxide

This study focused on steam gasification and reforming of waste biomass using a reforming catalyst. The purpose of the study was to evaluate the durability of a commercial Ni reforming catalyst and the effect of CaO on the reforming behavior, and to clarify detailed factors of catalytic performance, as well as the effect of operating parameters on the characteristics of produced gas composition. Moreover, catalyst regeneration was carried out and the behavior of catalytic activity based on gas composition was investigated. Using a fluidized bed gasifier and a fixed bed reformer, gasification and reforming of waste biomass were carried out. Commercial Ni-based catalyst and calcined limestone (CaO) were applied to the reforming reaction. Temperature of the gasifier and reformer was almost 1023 K. Ratio of steam to carbon in the feedstock [mol mol⁻¹] and equivalence ratio (i.e., ratio of actual to theoretical amount of oxygen) [-] were set at about 2 and 0.3, respectively. The feed rate of the feedstock into the bench-scale gasifier was almost 15 kg h⁻¹. The results of waste biomass gasification confirmed the improvement in H₂ composition by the CO₂ absorption reaction using the reforming catalyst and CaO. In addition, CaO proved to be especially effective in decreasing the tar concentration in the case of woody biomass gasification. Catalytic activity was maintained by means of catalyst regeneration processing by hydrogen reduction after air oxidation when woody biomass was used as feedstock.     

Determination of dioxin concentrations in fish and seafood samples using a highly sensitive reporter cell line, DR-EcoScreen cells

There is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in environmental and food samples. In this study, we applied a reporter gene assay using DR-EcoScreen cells (DR-cell assay), which is highly sensitive to dioxins, to the determination of PCDD/Fs and dl-PCBs in fish and seafood samples. The PCDD/Fs and dl-PCBs were extracted from homogenated samples (10 g) of 30 fish and shellfish, purified by clean-up procedure using a multilayered silica gel column and an alumina column, and applied to DR-cell assay. Interestingly, the bioanalytical equivalent (BEQ) values obtained from the DR-cell assay [<0.1 ∼ 5.4 pg BEQ g⁻¹ wet weight (ww)] were closely correlated with the toxicity equivalent (TEQ) values from conventional high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) analysis (r² = 0.912), and the slope of regression line was 0.913. Therefore, we multiplied the BEQ values from the DR-cell assay by a conversion coefficient (1.095, the reciprocal of 0.913) to approximate the TEQ values from the HRGC-HRMS analysis. Furthermore, we used this DR-cell assay to perform a prescreening test of PCDD/Fs and dl-PCBs in 16 fish and seafood samples purchased from a supermarket, revealing that a sample from the fatty flesh of a bluefin tuna exceeded 8 pg TEQ g⁻¹ ww (the European Union-tolerance limit). Taken together, these results suggest that the DR-cell assay might be applicable as a rapid and low-cost prescreening method to determine dioxin levels in fish and seafood samples.     

Coagulation characteristics of humic acid modified with glucosamine or taurine

To suppress the coagulation of humic acid (HA) in aqueous solutions, HA was modified with hydrophilic amines, such as glucosamine or taurine. These amines were attached to carboxyl groups in HA via amide bond formation. The degree of modification (R(m)) was estimated to be 21-38%. Infrared spectra of the modified HAs were also consistent with the presence of amide bonds. Acid-base titration showed that the average acid-dissociation constant (pK(app)) of the HA samples was increased by the modification. The Ca(2+) binding capacity of HA decreased with an increase in R(m) value. Critical pH or Ca(2+) concentration, at which HA coagulation occurs, was increased as the result of the modification. These critical points for taurine-HA were higher than those for glucosamine-HA. This is mainly due to electrostatic repulsion by sulfonate groups in taurine. These results indicate that the coagulation of HA is suppressed by modifying the molecules with glucosamine or taurine.     

Consideration on safety for emerging technology – Case studies of seven service robots

Despite the fact that several manufacturers of service robots launched their innovations into the market, worldwide guidelines or regulations concerning the safety aspects of service robots are not yet available. However the general principles and methodologies of safety of machinery (e.g., ISO/IEC Guide 51, partly ISO14121, ISO12100) could be implemented to a certain degree. The safety of seven service robots as an emerging technology was verified by safety professionals of “NPO – the Safety Engineering Laboratory” a Non Profit Organization. NPO verified the “Critical Hazards” for each service robot mentioned by the respective manufacturers. For those cases, both the “As Low As Reasonably Practicable” principle and the “Reasonable Alternative Design” standard were applied for judging if the risk associated with the Critical Hazards were tolerable or not and if state of the art measures for reducing the risk were applied adequately. These experiences will help to establish guidelines for the safety of service robots as an emerging technology in the future.     

Electrical and electronic waste management in China: progress and the barriers to overcome.

Serious adverse impacts on the environment and human health from e-waste recycling have occurred in the past and continue to occur in China today, due to a lack of national management strategies. China has made great efforts to face the challenges of the approaching peak increase in the domestic generation of e-waste and the illegal shipment of e-waste from other countries. This study examined recent progress and analysed the main problems associated with this issue in China. It was found that the material and the financial flows of e-waste in China had their own specific characteristics. Nearly 60% of the generated e-wastes were sold to private individual collectors and passed into informal recycling processes. More than 90% of Chinese citizens are reluctant to pay for the recycling of their e-waste. This is due to their traditional understanding that there remained value in these end-of-life products. Regulations concerning e-waste in China have been drafted but their deficiencies are obvious. The extended producer responsibilities (EPR) have been introduced but are not well defined. Eight formal facilities have been planned and are under construction or are in operation along the eastern coast of China but it will be difficult for them to compete with the informal processes for the reasons identified during the study.