Causes of haze in the Columbia River Gorge

Visibility impairment in the Columbia River Gorge National Scenic Area is an area of concern. A field study conducted from July 2003 to February 2005 was followed by data analysis and receptor modeling to better understand the temporal and spatial patterns of haze and the sources contributing to the haze in the Columbia River Gorge in the states of Washington and Oregon. The nephelometer light scattering and surface meteorological data at eight sites along the gorge showed five distinct wind patterns, each with its characteristic diurnal and spatial patterns in light scattering by particles (bsp). In summer, winds were nearly always from west to east (upgorge) and showed decreasing bsp with distance into the gorge and a pronounced effect of the Portland, OR, metropolitan area on haze, especially in the western portions of the gorge. Winter often had winds from the east with very high levels of bsp, especially at the eastern gorge sites, with sources east of the gorge responsible for much of the haze. The major chemical components responsible for haze were organic carbon, sulfate, and nitrate. Positive matrix factorization (PMF) using chemically speciated Interagency Monitoring of Protected Visual Environments data indicated seven source factors in the western gorge and five factors in the eastern gorge. Organic mass is a large contributor to haze in the gorge in all seasons, with a peak in fall. The PMF analysis suggests that approximately half of the organic mass is biomass smoke, with mobile sources as the second largest contributor. PMF analysis showed nitrates (important in fall and winter) mainly attributed to a generic secondary nitrate factor, with the next largest contributor being oil combustion at Mt. Zion, WA and mobile sources at Wishram, WA. Sulfate is a significant contributor in all seasons, with peak sulfate concentrations in summer.     

Municipal incineration bottom ash treatment using hydrothermal solidification

Solidification of municipal incineration bottom ash (MIBA) has been carried out using a hydrothermal processing method, in which the MIBA was first compacted in a mold at 5-20 MPa, and then hydrothermally cured in an autoclave under saturated steam pressure at 150-250 degrees C for 10-72 h. Experimental results showed that the tensile strength of the solidified body was greatly influenced by the addition of NaOH solution and fresh cement in the MIBA. The hydrothermal curing temperature and time exerted a significant influence on the development of tensile strength of solidified body. The strength development is speculated to be due primarily to the formation of 1.1 nm tobermorite. Laboratory leaching tests were conducted to determine the amount of heavy metals dissolved from the solidified bodies and the results showed that under the hydrothermal conditions of this study the leaching of heavy metals was very low. As such, the hydrothermal processing method may have a high potential for recycling MIBA.     

Catalytic reduction of sulfur dioxide with carbon monoxide over tin dioxide for direct sulfur recovery process

SO(2) reduction by CO over SnO(2) catalyst was studied in this work. The parameters were the reaction temperature, space velocity (GHSV) and [CO]/[SO(2)] molar ratio. The optimal temperature, GHSV and [CO]/[SO(2)] molar ratio were 550 degrees C, 8000 h(-1) and 2.0, respectively. Under these conditions, the SO(2) conversion and sulfur selectivity were about 78% and 68%, respectively. The following reaction pathway involving two mechanisms was proposed in SO(2) reduction by CO over SnO(2) catalyst: in the first step involving Redox mechanism, the elemental sulfur was produced by the mobility of the lattice oxygen between SO(2) and SnO(2) surface. In the second step, COS was formed by the side reaction between elemental sulfur and CO or metal sulfide and CO. In the third step involving COS intermediate mechanism, the abundant elemental sulfur was produced by the SO(2) reduction by COS which was produced in the second step and was more effective reducing agent than CO.     

钛元素对水培大白菜生长的促进作用

文章选用凡尔赛营养液作为基础培养液,分别加入一种含钛植物生长促进剂和TiCl4溶液,以早熟五号大白菜为试验对象,基础培养液作为对照,考察钛元素对大白菜生长的影响及与其他营养元素之间的关系。结果表明:施加含有相同含钛量的植物生长促进剂与TiCl4溶液的大白菜中单株大白菜鲜重增幅分别为35.4%和23.1%;可溶性糖含量增幅为162.5%及118.8%;大白菜中硝酸盐含量的降低幅度分别为15.2%和13.8%;亚硝酸盐含量的降低幅度分别为36.4%和33.8%。同时,还测量了其他相关指标如株高、叶面积、叶绿素含量等。添加TiCl4的培养液与对照相比,在各项指标中都表现出优势,与添加植物生长促进剂的培养液相比,叶绿素、硝酸盐等指标相差不明显。     

危化品泄漏围堵材料理化性能及燃烧行为研究

针对易燃液体泄漏围堵问题，开发了1种可快速发泡的酚醛泡沫材料，对其表观密度、耐水性、耐酸性、耐碱性、氧指数、燃烧行为及产烟成分进行系统研究。研究结果表明:发泡材料在中性和酸性液体环境中表现出良好的耐受性；在碱性环境中稳定性降低，由于共轭效应，导致分子中的H+遇碱性环境发生中和反应；发泡材料的氧指数和锥形量热测试参数（热释放速率、总热释放量及总生烟量等）表明该材料具有良好的耐火性；发泡原料中的含硫交联剂是其燃烧产烟生成较高浓度SO2的主要原因。     

人力资本、技术创新对环境污染的影响机制——基于全国285个城市的实证分析

基于2003~2016年中国285个城市数据，讨论了人力资本和技术创新对环境污染的影响机制。主要研究结论为：（1）人力资本和技术创新可以显著降低环境污染；（2）人力资本和技术创新对环境污染的影响存在协同作用，在人力资本的影响下，技术创新显现出明确的减污效应，同时在技术创新的影响下，人力资本也显现出明确的减污效应；（3）人力资本和技术创新跨越各自的门槛值后，二者的协同效应会增强，减污效果更明显；（4）人力资本和技术创新对环境污染的影响是通过“产业清洁效应”、“外资清洁效应”和“金融清洁效应”3类中介途径实现的。研究结论为我国环境污染的治理提供了有益的借鉴。     

三江源畜牧业示范区土壤重金属含量特征及评价

为了明确三江源智慧生态畜牧业示范区内土壤重金属元素含量特征及潜在风险,2015年7月在三江源智慧生态畜牧业示范区11个示范村镇进行土壤样品采集,带回实验室分析Pb、Cd、Hg、Cr、Cu、Zn、Ni含量。对数据进行统计分析并采用内梅罗综合污染指数和生态危害指数进行风险等级评价。结果显示:部分采样点重金属元素含量高于青海省背景值;Pb、Cr、Cu、Zn、Ni主要受土壤母质的影响,Cd受自然和人为因素的双重影响,Hg主要受人为因素影响;内梅罗综合污染指数显示11个点位的指数都小于1,该地未出现污染状况;生态危害指数显示除GMY点位处于轻微风险等级,其余采样点为中等风险等级。总体上示范区内土壤未出现强污染和面源污染状况,但需要加强点源污染的风险防范。     

高效液相色谱法测定土壤中多环芳烃的条件优化

研究了加速溶剂萃取(ASE)、固相萃取柱净化(SPE)、高效液相色谱仪(HPLC)联合测定土壤中16种多环芳烃(PAHs)的分析方法,选择以正己烷/丙酮(1+1,V/V)作为ASE提取溶剂,提取液经SPE硅胶小柱净化,正己烷/二氯甲烷(1+1,V/V)进行洗脱,洗脱体积为10 m L,洗脱液经旋转蒸发浓缩至近干,过0.22μm有机滤膜,用乙腈定容至1 m L,最后用HPLC-紫外检测器对提取液中16种PAHs进行定量分析。土壤中16种PAHs的方法检出限为2.8~4.9μg/kg,加标回收率为81.9%~102%,相对标准偏差为2.5%~6.2%,完全满足土壤中PAHs分析的质量控制要求,该法稳定性好、准确度高、可操作性强,适合于土壤样品中16种PAHs的准确测定。     

Recovery of iron oxide and calcium chloride from an iron-rich chloride waste using calcium carbonate

Journal of Material Cycles and Waste Management - The ilmenite-chloride process has used for the production of TiCl4 from the ilmenite (FeTiO3) ore, which produces cyclone dust containing mostly...     

Propagation,deposition, and suspension characteristics of constant-volume particle-driven gravity currents

Environmental Fluid Mechanics - In this laboratory study, propagation behaviour, particle deposition patterns, and suspension characteristics of non-cohesive particle-driven gravity currents formed...