Estimation of the daily soil/dust (SD) ingestion rate of children from Gansu Province,China via hand-to-mouth contact using tracer elements

A total of 60 children (31 males and 29 females) between the ages of 3 and 12 years were randomly selected from Lanzhou City in Gansu Province, northwest China. Hand (soil/dust) SD samples from these children were collected using hand wipes. We determined the approximate amounts of hand SD and the concentrations of three tracer soil elements (Ce, Y, and V) in these samples. The approximate amounts of hand SD ranged from 42.28 to 173.76 mg, with a median value of 85.42 mg. In addition, the mean amounts of hand SD estimated using the concentrations of Ce, Y, and V in the samples were 4.63, 3.43, and 3.42 mg, respectively. The amount of hand SD varied greatly among the age groups: primary school children had more hand SD than kindergarten children, males had more hand SD than females, and children from rural areas had more hand SD than those from urban areas. The rates of daily ingestion of hand SD for kindergarten and primary school children were estimated to be 7.73 and 6.61 mg/day, respectively.     

天然气集配气站综合防雷技术改造

随着天然气生产向自动化、网络化、智能化方向的迅猛发展,大部分天然气集配气站都建立和完善了自动计量、视频监控、生产数据传输、无线通讯等系统。但是随着电气仪表设备和数据线的增多,系统受雷击或因雷电影响受损的概率陡然增加,特别是近几年,天然气集配气站内计量、控制系统设备频繁出现雷击损坏现象。因此,对天然气集配气站实施综合防雷技术改造十分必要。     

Biotoxicity and bioavailability of hydrophobic organic compounds solubilized in nonionic surfactant micelle phase and cloud point system

Environmental Science and Pollution Research - A recent work has shown that hydrophobic organic compounds solubilized in the micelle phase of some nonionic surfactants present substrate toxicity to...     

In_2TiO_5纳米带的静电纺丝法制备及光催化性能

以酞酸丁酯(Ti(OC_4H_9)_4)、硝酸铟(In(NO3)3)和聚乙烯吡咯烷酮(PVP-K30)为原料,采用静电纺丝技术制备了In_2TiO_5纳米带.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-vis DRS)和氮气吸附-脱附等温线(BET)等技术对样品进行了表征.考察了In_2TiO_5纳米带在光催化降解罗丹明B(RhB)、甲基橙(MO)、亚甲基蓝(MB)和左氧氟沙星(LEV)过程中的应用性能,研究了不同离子型物质、溶液的pH和MB起始浓度对In_2TiO_5纳米带光催化活性的影响.结果表明:In_2TiO_5纳米带具有正交晶系结构,禁带宽度为3.47 eV,比表面积为20.71 m~2·g~(-1),可应用于4种不同离子型物质的光催化降解,发现光催化效果与被降解物质的表面带电性质有关.在紫外光照射下,90 min,对MB的降解率达98.1%,其降解过程服从一级动力学模型.     

Mg2+ improves biomass production from soybean wastewater using purple non-sulfur bacteria

Soybean wastewater was used to generate biomass resource by use of purple non-sulfur bacteria(PNSB). This study investigated the enhancement of PNSB cell accumulation in wastewater by Mg2+under the light-anaerobic condition. Results showed that with the optimal Mg2+dosage of 10 mg/L, biomass production was improved by 70% to 3630 mg/L,and biomass yield also was improved by 60%. Chemical Oxygen Demand(COD) removal reached above 86% and hydraulic retention time was shortened from 96 to 72 hr. The mechanism analysis indicated that Mg2+could promote the content of bacteriochlorophyll in photosynthesis because Mg2+is the bacteriochlorophyll active center, and thus improved adenosine triphosphate(ATP) production. An increase of ATP production enhanced the conversion of organic matter in wastewater into PNSB cell materials(biomass yield) and COD removal, leading to more biomass production. With 10 mg/L Mg2+, bacteriochlorophyll content and ATP production were improved by 60% and 33% respectively.     

人工湿地应用于富营养化景观水体修复

以某会议中心1号和2号人工湿地为研究对象,研究了人工湿地对富营养化景观水体的净化效果。结果表明:1号和2号人工湿地对COD、TN和TP均具有较好的处理效果,植物的差异对湿地污染物去除效果的影响不明显。TP的去除主要依靠基质的作用。湿地的前段和中段是整个湿地COD和TN去除的主体,且前段的去除率高于中段。     

Toward rational design of amines for CO2 capture: Substituent effect on kinetic process for the reaction of monoethanolamine with CO2

Amines have been considered as promising candidates for post-combustion CO₂ capture. A mechanistic understanding for the chemical processes involved in the capture and release of CO₂ is important for the rational design of amines. In this study, the structural effects of amines on the kinetic competition among three typical products (carbamates, carbamic acids and bicarbonate) from amines + CO₂ were investigated, in contrast to previous thermodynamic studies to tune the reaction of amines with CO₂ based on desirable reaction enthalpy and reaction stoichiometry. We used a quantum chemical method to calculate the activation energies (E_a) for the reactions of a range of substituted monoethanolamines with CO₂ covering three pathways to the three products. The results indicate that the formation of carbamates is the most favorable, among the three considered products. In addition, we found that the E_a values for all pathways linearly correlate with pK_a of amines, and more importantly, the kinetic competition between carbamate and bicarbonate absorption pathways varies with pK_a of the amines, i.e. stronger basicity results in less difference in E_a. These results highlight the importance of the consideration of kinetic competition among different reaction pathways in amine design.     

Removal of formaldehyde over MnxCe1-xO2 catalysts: Thermal catalytic oxidation versus ozone catalytic oxidation

MnxCe1- xO2（x： 0.3–0.9） prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde（HCHO）. At x = 0.3 and 0.5, most of the manganese was incorporated in the fluorite structure of Ce O2 to form a solid solution. The catalytic activity was best at x = 0.5, at which the temperature of 100% removal rate is the lowest（270°C）. The temperature for 100% removal of HCHO oxidation is reduced by approximately 40°C by loading 5 wt.% Cu Oxinto Mn0.5Ce0.5O2. With ozone catalytic oxidation, HCHO（61 ppm） in gas stream was completely oxidized by adding 506 ppm O3 over Mn0.5Ce0.5O2 catalyst with a GHSV（gas hourly space velocity） of 10,000 hr-1at 25°C. The effect of the molar ratio of O3 to HCHO was also investigated. As O3/HCHO ratio was increased from 3 to 8, the removal efficiency of HCHO was increased from 83.3% to 100%. With O3/HCHO ratio of 8, the mineralization efficiency of HCHO to CO2 was 86.1%. At 25°C, the p-type oxide semiconductor（Mn0.5Ce0.5O2） exhibited an excellent ozone decomposition efficiency of 99.2%,which significantly exceeded that of n-type oxide semiconductors such as Ti O2, which had a low ozone decomposition efficiency（9.81%）. At a GHSV of 10,000 hr-1, [O3]/[HCHO] = 3 and temperature of 25°C, a high HCHO removal efficiency（≥ 81.2%） was maintained throughout the durability test of 80 hr, indicating the long-term stability of the catalyst for HCHO removal.