南京夏季气溶胶吸湿增长因子和云凝结核的观测研究

为了更加全面地研究长三角地区气溶胶的理化特性,尤其是吸湿和活化特性,于2013年8月在南京市区对气溶胶的吸湿增长因子(GF)和云凝结核(CCN)展开相关观测研究.使用串联电迁移率颗粒物吸湿粒径分析仪(H-TDMA)观测32~350nm气溶胶在相对湿度为90%条件下的吸湿性参数,使用云凝结核计数器(CCNC)观测过饱和度在0.2%~0.8%的CCN数浓度.结果表明,不同气溶胶粒子的吸湿增长行为均表现出较为明显的双峰分布,即一个强吸湿模态和一个弱吸湿模态,且吸湿性在不同粒径(爱根核模态和积聚模态)上存在较为明显的不同,不溶性物质和二次气溶胶所占比重较大,并且在稳定的天气条件下,气溶胶的混合状态表现为由外混向内混发展的过程.观测期间该区域CCN的平均数浓度为13776(0.6%)cm-3,比沿海区、山区、干旱地区及清洁城市地区要高很多.其日变化表现为中午时刻出现峰值,影响因素主要与光化学反应有关.同时25日出现的轻雾过程对CCN有较为明显的清除作用.通过吸湿性参数计算得到的CCN数浓度和实际观测得到的CCN数浓度进行了闭合实验,结果显示出较好的相关性,表明将未饱和条件下观测得到的吸湿性参数带入到K?hler方程中,即可预测过饱和条件下气溶胶的活化能力.     

有机废气中VOC的回收方法

介绍了炭吸附法、冷凝法和膜分离法回胥机废报中ＶＯＤ的原理、工艺流程和工业应用情况，并对这些方法进行了比较，指出了适用范围。     

双分离层复合纳滤膜的制备及其性能

以改性后的聚丙烯腈(PAN)超滤膜为基膜,依次采用层层自组装(LBL)和界面聚合的方法制备了具有双层分离层的复合纳滤膜。以间苯二胺(MPD)为水相单体,均苯三甲酰氯(TMC)为有机相单体,聚乙烯亚胺(PEI)为阳离子聚电解质,聚(4-苯乙烯磺酸钠)(PSS)为阴离子聚电解质,探索了LBL条件对双分离层复合纳滤膜性能的影响,考察了通过不同制备方法获得的纳滤膜对硫酸镁(MgSO4)的分离性能,得到了最佳的LBL制备条件：PEI溶液的浓度为1.00 g·L-1,pH为7;PSS溶液的浓度为1.00 g·L-1,pH为10,支撑电解质氯化钠(NaCl)浓度为1.00 mol·L-1,单一聚电解质(PEI或PSS)的沉积时间为20 min。与仅通过界面聚合法制得的聚酰胺纳滤膜相比,在界面聚合反应之前,先通过LBL沉积1.5层的聚电解质层时得到的复合纳滤膜分离性能优异稳定,在0.80 MPa的压力下,过滤2.00 g·L-1 MgSO4溶液时的通量为18.6 L·(m2·h)-1,截留率达到99.07%。     

Application of a Second-Order Kinetic Model to a Complex Melt Polymerization Reaction

A novel copolymer system has been synthesized using methyl hydroquinone diacetate (MHQDA), 1,4 naphthalene dicarboxylic acid (1,4 NDCA), and polybutylene terephthalate (PBT) using the melt polymerization technique. The optimum kinetic parameters pertinent to this system are reported in this study. A simple second-order reaction sequence summarizes catalyzed and uncatalyzed reactions between MHQDA, 1,4 NDCA, and PBT. The kinetic parameters for the copolymerization reaction were determined using a new second-order model. This technique was used to compute the moles of acetic acid generated in the polymerization process. The model was compared to that of the experimentally determined data. Close comparison (percentage error of less than 5%) was obtained between the experimental and theoretical data. The kinetic data support block copolyester formation. The thermal data also supports formation of block polymers.     

膜的改性及其在环境领域应用研究进展

膜改性由于具有清洁、廉价、节能等特点,近年来得到快速发展,是解决膜污染的有效方法之一。本文综合介绍了膜的基体改性、表面改性这两种改性类型和目前常用的改性方法包括表面涂覆、表面活性剂改性、化学修饰改性、仿生改性等等,并简单介绍了膜改性在环境领域的应用,探讨了膜改性今后的发展。     

Key features of new particle formation events at background sites in China and their influence on cloud condensation nuclei

New particle formation (NPF) event at multi rural sites in China Identifying the characteristics of NPF event Comparing NPF event between clean and polluted conditions Quantifying contribution to the cloud condensation nuclei Implication of climate and air quality Long-term continuous measurements of particle number size distributions with mobility diameter sizes ranging from 3 to 800 nm were performed to study new particle formation (NPF) events at Shangdianzi (SDZ), Mt. Tai (TS), and Lin’an (LAN) stations representing the background atmospheric conditions in the North China Plain (NCP), Central East China (CEC), and Yangtze River Delta (YRD) regions, respectively. The mean formation rate of 3-nm particles was 6.3, 3.7, and 5.8 cm⁻³·s⁻¹, and the mean particle growth rate was 3.6, 6.0, and 6.2 nm·h⁻¹ at SDZ, TS, and LAN, respectively. The NPF event characteristics at the three sites indicate that there may be a stronger source of low volatile vapors and higher condensational sink of pre-existing particles in the YRD region. The formation rate of NPF events at these sites, as well as the condensation sink, is approximately 10 times higher than some results reported at rural/urban sites in western countries. However, the growth rates appear to be 1–2 times higher. Approximately 12%–17% of all NPF events with nucleated particles grow to a climate-relevant size (>50 nm). These kinds of NPF events were normally observed with higher growth rate than the other NPF cases. Generally, the cloud condensation nuclei (CCN) number concentration can be enhanced by approximately a factor of 2–6 on these event days. The mean value of the enhancement factor is lowest at LAN (2–3) and highest at SDZ (~4). NPF events have also been found to have greater impact on CCN production in China at the regional scale than in the other background sites worldwide.     

四川乡村点新粒子生成特征及其对云凝结核数浓度的贡献

为揭示成渝地区大气复合污染成因,选择乡村点资阳站的冬季,实测了颗粒物数浓度及其粒径谱分布、云凝结核(CCN),在二氧化硫、光解速率(JO1D)实测值基础上估算了新粒子生成的重要前体物气态硫酸的浓度.2012年12月5日到2013年1月5日观测期间,3~582nm颗粒物数浓度水平较高,平均值为(16072±9713)cm-3.颗粒物数谱分布呈现以积聚模态为主体的特征,占总颗粒物数浓度的46%,此比值高于我国北京、上海、广州等城市和珠江三角洲及长江三角洲的乡村点和背景点.在较高颗粒物凝结汇(CS)水平下[(4.3±3.6)×10-2s-1],甄别出7次新粒子生成(NPF)事件,占观测天数的23%.NPF事件发生时,颗粒物生成速率与增长速率分别为(5.2±1.4)cm-3s-1,(3.6±2.5)nm/h. NPF事件对CCN数浓度有明显贡献,NPF发生后CCN数浓度平均增长19%.     

聚合反应时间对聚酰亚胺基碳膜结构和性能的影响研究

目的 系统研究前驱体聚合反应时间对PI膜及其碳化、石墨化后薄膜结构和性能的影响规律。方法 通过调整聚合合成聚酰胺酸（PAA）溶液过程中的反应时间,制备石墨膜前驱体聚酰亚胺（PI）原膜,将不同工艺条件下制得的PI膜进行碳化、石墨化处理,得到高导热率石墨膜。利用扫描电镜、红外光谱、拉曼光谱仪和LFA激光闪射仪对制备的PI膜、碳化膜及石墨膜的微观结构和热导率进行检测。结果 随聚合反应时间的延长,PI膜酰亚胺化程度和石墨膜的石墨化程度及导热性能先增高、后降低。反应时间为3 h时,制得的石墨膜结构致密,石墨片层取向性好,导热性能最好,热导率可达765.2W/(m·K)。结论 PI膜前驱体聚合反应时间显著影响PI膜酰亚胺化的程度和有序度,进而影响石墨膜的定向性和导热性能。     

聚硅氯化铝混凝剂中Al(Ⅲ)水解聚合历程及铝硅作用特性研究

采用共聚与复合两种制备工艺，制备出了系列具有不同碱化度和不同Ａｌ／Ｓｉ摩尔比的聚硅氯化铝混凝剂，分析研究了ＰＡＳＣ中Ａｌ（Ⅲ）的水解－聚合历程以及聚硅酸与铝水解聚合产物的相互作用，探讨了ＰＡＳＣ溶液的酸解聚。     

水泥窑共处置过程中水泥生料对砷的吸附/冷凝特性

针对水泥生料开展了氮吸附与SEM测试分析,研究了水泥生料的比表面积,孔径结构和微观表面积。同时,利用管式回转炉和控温立式炉联用装置研究了砷元素在水泥生料上的吸附冷凝特性。结果表明,水泥生料的比表面积很小,微观表面结构致密无孔,砷元素主要是冷凝在生料表面上。进入吸附冷凝炉的重金属可以分为3部分,第1部分冷凝在管壁上,占80%左右;第2部分吸附/冷凝在生料上,占10%左右;第3部分随烟气释放到空气中,不到10%。水泥生料对砷的吸附冷凝量随时间的增加而增加,随温度的升高而降低。水泥生料对砷的吸附冷凝特性可用双常数速率方程拟合,拟合效果较好,计算得表观活化能在6~7 kJ/mol之间。此外,砷的初始浓度对水泥生料的吸附冷凝特性影响很小。