生活垃圾焚烧厂渗滤液生化出水的混凝机理研究

分别采用Al₂(SO₄)₃、FeCl₃、PAC、PAFC对垃圾焚烧厂渗滤液生化出水进行混凝研究,并建立混凝处理模型.结果表明,在pH值为6时,单独投加500 mg/L的Al₂(SO₄)₃、FeCl₃、PAC、PAFC时,COD去除率分别为20％、17％、30％、40％.焚烧厂渗滤液生化出水中有机物主要是由相对分子质量小于2 000的可溶性物质组成;通过透射电镜扫描技术(TEM)和Zeta电位分析,发现中和及网捕桥联是渗滤液混凝处理的主要作用机理;相比无机盐混凝剂,聚合物混凝剂具有较强的电中和以及网捕架桥功能.     

Effect of additive on the formation of polyacrylonitrile membrane

The effect of additives CaCl2 and CaCl2/H2O on the properties of polyacrylonitrile(PAN) ultrafiltration(UF) membranes prepared by phase inversion process was studied. The dissolving capacity of the casting solution for CaCl2 was enhanced by the addition of H2O. The membranes are characterized in terms of the pure water flux and molecular weight cut-off(MWCO). The addition of CaCl2 or CaCl2/H2O to the casting solution increases the resulting membrane permeability.     

A review of environmental characteristics and effects of low-molecular weight organic acids in the surface ecosystem

Low molecular weight organic acids （LMWOAs） are prevalent on the earth＇s surface. They are vital intermediate products during metabolic pathways of organic matter and participate in the tricarboxylic acid cycle during life activities. Photochemical reactions are pivotal for LMWOAs＇ origination and play a large role in determining their diversity and their ultimate fate. Within the long time that organic matter is preserved in sediments, it can be decomposed and converted to release organic and inorganic pollutants as well as C, N, and P nutrients, which are of potential ecological risk in causing secondary pollution to lake water. The sediment pool is a comprehensive and complex compartment closely associated with overlying water by various biochemical processes, during which LMWOAs play critical roles to transport and transform elements. This article elucidates geochemical behaviors of LMWOAs in the surface environment in details, taking natural water, soil, and aerosol as examples, focusing on reviewing research developments on sources and characteristics, migration and mineralization of LMWOAs and relevant environmental effects. Simultaneously, this review article depicts the categories and contents of LMWOAs or their contribution to DOC in environmental media, and evaluates their importance during organic matter early diagenesis. Through concluding and discussing the conversion mechanisms and influencing factors, the next research orientations on LMWOAs in lake ecosystems are determined, mainly concerning relationships with hydrochemical parameters and microorganisms, and interactions with pollutants. This will enrich the knowledge on organic matter degradation and related environmental effects, and help reconstruct a theoretical framework for organic compound succession and influencing factors, providing basic data for lake eutrophication and ecological risk assessment, conducive to better control over water pollution and proper management of water quality.     

聚乙烯乙二醇膜处理含油废水的影响因素研究

采用不同截留分子量的聚乙烯乙二醇超滤膜（PEG），在连续错流式操作条件下用于处理乳化液废水，考察了压力、温度对透水率和CODcr去除率的影响。结果表明：超滤膜处理乳化液废水的透水率受操作压力和温度的影响．对于截留分子量为8000的超滤膜。应选择0．3～0．7MPa的操作压力；而对于截留分子量为2500的超滤膜，应选择0．7～1．0MPa的压力；同时，超滤膜的温度范围选择为25～32℃。采用截留分子量2500的聚乙烯乙二醇超滤膜，在温度28℃和压力0．5MPa条件下处理乳化液废水，CODcr去除率可达93％左右。     

Effects of ozonation and coagulation on effluent organic matter characteristics and ultrafiltration membrane fouling

Effluent organic matter （EfOM） is the major cause of fouling in the low pressure membranes process for wastewater reuse. Coagulation and oxidation of biological wastewater treatment effluent have been applied for the fouling control of microfiltration membranes. However, the change in EfOM structure by pre-treatments has not been clearly identified. The changes of EfOM characteristics induced by coagulation and ozonation were investigated through size exclusion chromatography, UV/Vis spectrophotometry, fluorescence spectrophotometry and titrimetric analysis to identify the mechanisms in the reduction of ultrafiltration （UF） membrane fouling. The results indicated that reduction of flux decline by coagulation was due to modified characteristics of dissolved organic carbon （DOC） content. Total concentration of DOC was not reduced by ozonation. However, the mass fraction of the molecules with molecular weight larger than 5 kDa, fluorescence intensity, aromaticity, highly condensed chromophores, average molecular weight and soluble microbial byproducts decreased greatly after ozonation. These results indicated that EfOM was partially oxidized by ozonation to low molecular weight, highly charged compounds with abundant electron- withdrawing functional groups, which are favourable for alleviating UF membrane flux decline.     

手工法与自动监测法测定PM2.5质量浓度比对研究

采用小流量颗粒物采样器手工采样重量法和基于微振荡天平原理自动监测法监测PM2.5质量浓度。通过2010年9月至2011年8月期间两种方法的监测数据比对显示出季节差异,冬、春两季手工法获得质量浓度高于自动法,夏、秋两季手工法低于自动法,可能与两种采样方法下膜置于不同的温度有关。当受沙尘影响、持续污染或者高温污染时,两种方法结果偏差较大,可能与仪器的粒径切割效率改变有关。     

基于虚拟撞击原理的固定源PM10/PM2.5采样器的研制

目前我国尚无固定源PM2.5采样标准方法,现有商业化的固定源PM2.5采样器在使用中存在明显不足,因此本研究开发了一种固定源PM10/PM2.5双级虚拟撞击采样器.经实验室标定,该采样器切割效率曲线优于国际标准ISO 7708:1995对采样器的规定,采样器横截面直径为74 mm,满足我国固定源采样口尺寸要求.采样器既可以安装滤膜,也可以安装滤筒,适用于不同浓度的烟尘采样.虚拟撞击器的切割点与次流所占比值呈负相关,比值减小时,切割点增大.为降低颗粒物损失,虚拟撞击器喷嘴距收口的距离至少应为喷嘴直径的1.5~2倍.     

PM1切割器性能测试系统的搭建与应用

为对PM_1切割器的性能进行准确评估,本文设计搭建了两套PM_1切割器性能测试系统.结果发现,多分散气溶胶测试系统发生的气溶胶稳定、均匀,符合对数正态分布;单分散气溶胶测试系统发生的气溶胶稳定,单分散性良好.采用上述两套系统对5种PM1旋风切割器进行了性能评价,结果表明,两套系统测试结果基本一致,5种旋风切割器的切割粒径D50均在(1.0±0.1)μm之间,sharp-cut和Stairmand两类结构设计的切割器几何标准偏差σg分别在1.2±0.1和1.4±0.1之间.     

中心切割顶空气相色谱法测定复杂有机废水中的苯系物

建立了中心切割顶空气相色谱法测定复杂有机废水中苯系物的方法。该方法采用DB-1701色谱柱对样品进行初级分离,当目标组份出峰流出时切换至HP-INNOWAX柱进一步分离,避免了大量复杂基质对苯系物分析的干扰。该方法具有较好的准确度和精密度,苯系物的检测限可达到0.000 3~0.000 4 mg/L,采用外标法定量时,分析标准曲线的相关系数在0.999 8~0.999 9之间,苯系物回收率为86.8%~89.7%。     

水生腐殖酸分子量分布研究——Ⅰ.串联凝胶色谱法测定水生腐殖酸分子量分布

考察了测定水生腐殖酸分子量分布及其平均分子量的串联凝胶色谱法。结果表明,使用Sepbadex G-25和G-100两种凝胶的色谱柱系统的分离范围可从分子量1000左右到数万,几乎包括了水生腐殖酸分子量分布的整个区段。这样的串联凝胶色谱柱的标定曲线为一折线,可用分段函数近似地加以描述。