DOM纳滤膜污染及对膜截留卡马西平性能的影响

研究了天然原水中溶解性有机物(DOM)对HL和ESNA1-K两种纳滤膜造成的膜污染及其对膜截留卡马西平(CBZ)性能的影响.结果表明,DOM的存在造成了严重的膜污染和通量衰减.膜污染对CBZ截留率的影响与膜本身的特性和污染物特性有关,DOM通过在膜表面形成污染滤饼层和进入膜孔内部造成的膜孔堵塞,影响弱疏水性的CBZ从水中的分离,青草沙水库原水中的DOM引起的膜污染提高了两种纳滤膜对CBZ的截留效果,而太湖DOM造成的膜污染会降低CBZ的截留效果.研究还发现,中等相对分子质量(1 500~10 000)有机物会紧密地黏附在膜表面形成滤饼层,从而改变膜表面的疏水性能,小分子主要通过进入膜孔导致膜孔径堵塞.滤饼层的疏水性和浓差极化作用以及膜孔径的堵塞造成膜通量衰减并影响CBZ去除率.应用XDLVO理论对DOM造成的膜污染的分析结果表明,太湖DOM的疏水性明显强于青草沙DOM,其分子间的聚合自由能更负,与膜的黏附自由能更负,因而造成的膜污染和通量衰减更严重.     

正常污泥和膨胀污泥中EPS膜污染特性及其与膜表面作用能分析

胞外聚合物(Extracellular polymeric substance,EPS)是导致膜污染的重要物质,且不同形态污泥的EPS具有不同的性质,研究正常污泥和膨胀污泥的EPS膜污染特性具有重要意义.因此,实验考察了正常污泥和膨胀污泥的膜污染速率.结果表明,膨胀污泥膜污染速率远高于正常污泥,膨胀污泥EPS(Bulking sludge-EPS,BS-EPS)浓度((172.9±10.4) mg·g-1)明显高于正常污泥EPS(Normal sludge-EPS,NS-EPS)浓度((95.9±6 6) mg·g-1),且膨胀污泥的蛋白质/多糖(Protein/Carbohydrate,P/C)值(2.26)高于正常污泥的P/C值(1 97)此外,通过序批式吸附实验研究了正常污泥和膨胀污泥的EPS膜污染差异,并基于Derjaguine-Landaue-Verweye-Overbeek (XDLVO)理论计算了EPS与PVDF膜表面之间的作用能结果表明,EPS-膜系统的总界面能为负值,即EPS-膜系统之间会发生自吸附行为,而膜与BS-EPS的总界面能(-63.943mJ.m2)较膜与NS-EPS(-56.366 mJ·m2)具有较高的能量,因此,BS-EPS与膜的吸附力较强;NS-EPS和BS-EPS主要能量壁垒分别为8.89 kT和7.51 kT,表明NS-EPS与膜之间的排斥力更强,因而BS-EPS更容易造成膜污染     

放射性废水的膜处理技术研究进展

核燃料的生产、核电厂的运行、同位素的生产和使用等过程都会产生着大量的放射性废水,为了保护环境和人类健康,这些废水必须经过安全、经济和有效的处理处置.放射性废水传统的处理方法主要包括过滤法、离子交换法、蒸发法或这几种工艺的组合.近年来,膜分离技术在放射性废水处理中得到了广泛的研究,发达国家已有应用膜分离技术处理放射性废水的实例,而我国规模化应用的实例还很少见.本文首先介绍了放射性废水的来源及组成,分析了各种放射性废水处理方法的优势和不足,包括化学沉淀法、过滤法、离子交换法、蒸发浓缩法、吸附法、生物还原/吸附法和膜分离法等.在此基础上,重点介绍了各种膜分离技术,包括微滤、超滤、纳滤、反渗透、膜蒸馏等在放射性废水处理中研究与应用现状,对已有的文献资料进行了较系统全面的分析、归纳和总结,对各种方法的优缺点及适用范围进行了比较,对膜技术在放射性废水处理中的应用前景及问题进行了讨论.最后,简要介绍了放射性废水处理产生的浓缩产物的最终处理处置,对放射性废水处理技术未来的研究和发展方向给出了建议.     

沉积物中雌激素及壬基酚、辛基酚、双酚A的测定

近些年来雌激素及烷基酚类化合物由于其对水生生物的内分泌干扰作用越来越受到广泛关注.沉积物作为环境中有机污染物的重要储存库,研究目标物在其中的浓度分布对于探明此类物质在环境中的迁移转化具有重要意义.但沉积物中基质组成复杂而雌激素又痕量存在,这增加了前处理的难度.本研究从雌激素及烷基酚类化合物的理化性质入手,采用碱液提取、液液萃取和LC-MS/MS分析测定沉积物样品中的雌激素及壬基酚、辛基酚、双酚A.结果表明,经过优化的方法对7种目标物的回收率介于61.9%～93.7%之间.该方法能有效去除沉积物中那些不溶于强碱和既溶于酸又溶于碱的有机污染物,同时操作简单、成本低,但回收率高、检出限低,可广泛适用于河流沉积物样品及土壤样品的前处理.     

天然有机物的相对分子质量分布及亲疏水性对微滤膜组合工艺中膜污染的影响

研究采用混凝沉淀+粉末活性炭吸附+高锰酸钾+浸没式微滤膜的组合工艺对太湖水进行中试试验,通过高效凝胶色谱(HPSEC-UV-TOC)和三维荧光(3DEEM)的测定方法,着重考察有机物的相对分子质量(Mr)分布和亲疏水性对膜不可逆污染的影响.凝胶色谱分析表明:预处理可几乎完全去除大分子有机物(Mr>10×103),但仅能去除部分的中等分子(10×103>Mr>1×103)和小分子(Mr<1×103)有机物.研究发现化学清洗水中的有机物相对分子质量多为中等分子和小分子,说明导致膜不可逆污染的主要是中等分子和小分子有机物.此外,洗膜水中强疏和中性亲水组分含量远高于弱疏和极性亲水,说明强疏和中性亲水组分是不可逆污染的主要物质.三维荧光分析表明,芳香族蛋白质和溶解性微生物产物是造成膜不可逆污染的主要污染物.     

Application of comprehensive two-dimensional gas chromatography with mass spectrometric detection for the analysis of selected drug residues in wastewater and surface water

Pharmaceutical residues have become tightly controlled environmental contaminants in recent years, due to their increasing concentration in environmental components. This is mainly caused by their high level of production and everyday consumption. Therefore there is a need to apply new and sufficiently sensitive analytical methods, which can detect the presence of these contaminants even in very low concentrations. This study is focused on the application of a reliable analytical method for the analysis of 10 selected drug residues, mainly from the group of non-steroidal anti-inflammatory drugs (salicylic acid, acetylsalicylic acid, clofibric acid, ibuprofen, acetaminophen, caffeine, naproxen, mefenamic acid, ketoprofen, and dicofenac), in wastewaters and surface waters. This analytical method is based on solid phase extraction, derivatization by N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) and finally analysis by comprehensive two-dimensional gas chromatography with Time-of-Flight mass spectrometric detection (GC×GC- TOF MS). Detection limits ranged from 0.18 to 5 ng/L depending on the compound and selected matrix. The method was successfully applied for detection of the presence of selected pharmaceuticals in the Svratka River and in wastewater from the wastewater treatment plant in Brno-Modrice, Czech Republic. The concentration of pharmaceuticals varied from one to several hundreds of ng/L in surface water and from one to several tens of μg/L in wastewater.     

漆酶的逆胶束萃取条件优化的研究

研究了生物表面活性剂逆胶束体系萃取纯化漆酶的后萃的过程.在此逆胶束体系中,表面活性剂采用一种阴离子生物表面活性剂鼠李糖脂(rhamnolipid, RL),溶剂采用异辛烷.分别考察了4种不同离子种类(NaCl, NaBr, KCl和KBr)与不同浓度、4种不同助溶剂种类(正丁醇,正己醇,正庚醇及正辛醇)与不同比例、乙醇的含量以及温度对漆酶的后萃过程的影响.结果表明,0.25mol/L KCl或0.20mol/L KBr能够得到较好的萃取效果;在四种助溶剂中,正己醇(比例为0.5)和正庚醇(比例为0.5)效果比较好;乙醇加入量为9%效果最优;最适宜温度为35℃.在上述条件下,漆酶的酶活回收率和纯化倍数分别高达90%,4.7倍.电泳分析结果进一步证实了漆酶的纯化效果较好.研究证明鼠李糖脂逆胶束萃取酶类具有广阔的应用前景.     

Determination of 4-tert-octylphenol in surface water samples of Jinan in China by solid phase extraction coupled with GC-MS

Octylphenols, considered as xenoestrogens, mainly exist as 4-tert-octylphenol (OP) in aquatic environments. The high stability and accumulation of OP in aquatic systems have caused endocrine disruption. The OP in surface water in Jinan, China was analyzed by gas chromatography-mass spectrometry (GC-MS) coupled with solid phase extraction (SPE). Water samples were extracted by SPE on a cartridge system containing C-18 as sorbent. To increase sensitivity and selectivity, OP was derivatized to 4-tert-octyl-phenoxy silane. With the use of phenanthrene-d10 as internal standard, the detection limit based on signal-to-noise ratio (S/N = 3) was 0.06 ng/mL. The average recovery was from 84.67% to 109.7%. The precision of the method given as the relative standard deviations (RSD) was within the range 6.24%-12.96%. In the target water samples, the concentrations of OP were as follows: 15.88-71.24 ng/L for Jinxiuchuan Reservoir, 3.850-26.68 ng/L for the city moat, 6.930-41.56 ng/L for Daming Lake, 66.03-474.2 ng/L for Xiaoqing River, 14.66-17.72 ng/L for the Yellow River, and 10.60-26.43 ng/L for Queshan Reservoir. The Xiaoqing River was seriously polluted due to the discharge of wastewater from Jinan. Jinxiuchuan Reservoir had a higher concentration of OP compared with the Yellow River and Queshan Reservoir, which is ascribed to the surrounding human activities. These data are reported for the first time, providing strong support for the control of OP pollution in Jinan.     

预富集技术在原子吸收光谱环境分析中的应用

原子吸收光谱法是分析环境水样中金属离子含量的有效方法之一。在测定时往往需要对样品进行前处理,然后再进行测定。文章介绍了近些年较新的一些分离富集技术在原子吸收光谱分析环境中金属离子时的应用,分析了离子交换树脂在样品中金属离子富集分离过程中的研究近况,评述了固相萃取、析相微萃取、单滴液滴微萃取、分散液液微萃取、离子液体萃取、浊点萃取等多种萃取方式在样品预富集中的应用进展,综述了活性炭、纳米粒子、淀粉、分子筛等吸附剂在富集环境水样中金属元素的应用现状,同时还对在线富集技术与流动注射分析技术联用在金属元素分析中的应用进展进行了评述。