Phase separation and regrowth of aerosol matter collected after size fractionation in an impactor

Aerosol matter in the size range <2 μm was collected in a Berner impactor and subsequently analysed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrometry. Owing to the low electron beam energy of 5 keV (occasionally 10 keV), analysis was restricted to elements with atomic numbers 20 (Ca). Sub-micrometer aerosol matter was found to contain mostly S, O, and C as well as some K and Ca. Nitrogen appeared to escape detection, probably due to bombardment-induced sublimation of NO₃ and NH₄. During sampling at low to moderate relative humidity (<60%) the sulphur-rich fraction of the aerosol matter (most likely sulphates) regrew in the form of microcrystals with sizes up to 10 times larger than the mean aerodynamic diameter of the respective impactor stage. By contrast, when sampling during periods in course of which the relative humidity exceeded 70%, the aerosol matter regrew in the form of extended amorphous agglomerates. The aerosol deposits also contained large numbers of carbon nanoparticles, well separated from the regrown sulphate-rich matter. The nanoparticles were similar in size (20–40 nm), much smaller than the equivalent aerodynamic diameter of the impacting particles (63 nm–2 μm). Presumably, the carbon nanoparticles constituted the core of larger air-borne particles covered with sulphates (as well as with nitrates and organic carbon). The regrown microcrystals disappeared rapidly under electron bombardment at high current density, an observation that indicates high volatility at elevated temperatures. Aerosol matter collected in the size range between 1 and 2 μm contained large fractions of particles made of O, Si, P, K, and Ca (oxides). These particles were highly resistant to electron bombardment (hard) and showed little or no evidence for agglomeration or regrowth. After removing the soluble (acidic) material from the collected aerosol matter, only carbon nanoparticles and hard coarse particles were left behind. The observation of agglomerated or crystallized “soft” aerosol matter in combination with phase separation of carbon nanoparticles lends further support to the assertion that it is not possible to collect useful quantities of fine and ultrafine aerosol particles with as-suspended morphology. Some implications for health-related research are discussed.     

聚四氟乙烯微孔膜脱硫实验研究

采用聚四氟乙烯微孔膜脱除工业尾气中的SO2,研究了膜孔径、膜厚度、吸收液浓度、吸收流流速和进气速率等因素对脱硫效率的影响,为膜脱硫工业应用提供了参考数据。     

Source separation recycling schemes: A survey

Municipal waste arisings continued to increase during the 1970s in all the industrialized economies. Currently, in the midst of a severe international economic recession, the continuing escalation in the costs of waste disposal poses significant problems for municipal authorities. With the data constraints firmly in mind, this paper estimates the secondary materials supply potential of the municipal waste stream. The calculations suggest that a significant supply potential remains to be utilized despite ‘respectable’ overall recycling rates in most industrial economies. Resource recovery options can be divided into ‘low technology’ source separation schemes and ‘high technology’ mechanical separation schemes. The authors concentrate on the former option and appraise (on the basis of social cost-benefit analysis) a number of schemes that have operated in both Europe and North America.     

火场残留助燃剂的提取分离及气相色谱/质谱分析

本文总结了从火灾现场提取样品中分离残留助燃剂的常用方法,比较了各种不同分离方法的优缺点及主要适用对象,并介绍了常见助燃剂的典型气相色谱/质谱图特性,为火灾调查识别的研究提供理论指导。     

水力旋流沉淀器在精对苯二甲酸废水处理中的应用

阐述了新型SXD水力旋流沉淀器的工作原理及结构特点，并从理论和实际应用两方面分析了影响水力旋流器处理效果的因素，评价了其在精对苯二甲酸废水处理中的性能。     

孤东油田含油污泥现状及处理技术

含油污泥是油田开发过程中的重要污染源,孤东油田目前对含油污泥主要采用自然干化填埋处理法。为了更好地回收原油,提高环境效益和经济效益,实验用离心分离法处理含油污泥,结果表明:使用该技术使油回收率可以达到80%以上。当含油量达到一定值时,会产生明显的经济、环境及社会效益。     

溢油分离回收的神妙武器

20世纪90年代以来,国内外在陆上和海域不断发生溢油事故,由此造成重大的资源损失和环境污染。文中介绍了欧美国家对此采取的应急措施和使用的应急装备,论述了日本世界化工股份公司溢油分离回收机的工作原理、结构特点和适用环境。     

AVERAGE DISCHARGE,PERENNIAL FLOW INITIATION,AND CHANNEL INITIATION ‐ SMALL SOUTHERN APPALACHIAN BASINS1

ABSTRACT: Regional average evapotranspiration estimates developed by water balance techniques are frequently used to estimate average discharge in ungaged streams. However, the lower stream size range for the validity of these techniques has not been explored. Flow records were collected and evaluated for 16 small streams in the Southern Appalachians to test whether the relationship between average discharge and drainage area in streams draining less than 200 acres was consistent with that of larger basins in the size range (> 10 square miles) typically gaged by the U.S. Geological Survey (USGS). This study was designed to evaluate predictors of average discharge in small ungaged streams for regulatory purposes, since many stream regulations, as well as recommendations for best management practices, are based on measures of stream size, including average discharge. The average discharge/drainage area relationship determined from gages on large streams held true down to the perennial flow initiation point. For the southern Appalachians, basin size corresponding to perennial flow is approximately 19 acres, ranging from 11 to 32 acres. There was a strong linear relationship (R²= 0.85) between average discharge and drainage area for all streams draining between 16 and 200 acres, and the average discharge for these streams was consistent with that predicted by the USGS Unit Area Runoff Map for Georgia. Drainage area was deemed an accurate predictor of average discharge, even in very small streams. Channel morphological features, such as active channel width, cross‐sectional area, and bankfull flow predicted from Manning's equation, were not accurate predictors of average discharge. Monthly baseflow statistics also were poor predictors of average discharge.     

脱除烟气中SO2和NOx的新技术

综述了近年来新开发的脱除烟气中ＳＯ２及ＮＯｘ的新技术，包括膜技术、电化学技术及结合化学反应的高能辐射技术（电子束照射、等离子体电晕放电等），经过不断改进，其中有些技术已处于中试阶段，显示出了一定的应用前景。     

催化裂化催化剂的磁分离及再生回用技术的发展

重点介绍了国内外关于催化裂化平衡催化剂的化学再生方法（ＤＥＭＥＴ工艺）与物理分离方法（磁分离工艺）的机理、工艺及应用现状，提出了上述工艺在我国应用的前景及方向。