饮用水水质标准与水系传染病

介绍了世界卫生组织 ( WHO)、欧盟 ( EC)和美国环保局 ( USEPA)所制订的饮用水水质标准的特点 ,指出了我国饮用水水质标准与这三部标准的差距与不足 .着重对饮用水标准中微生物指标的确定进行了讨论 ,指出了病原微生物 (如沙门氏菌、霍乱弧菌、军团菌、脊髓灰质炎病毒、隐孢子虫及贾第虫等 )所引起的一些水系传染病 ,介绍了控制原生动物的几项有效措施 .     

水性环氧树脂对聚丙烯纤维混凝土性能影响的研究

以改性水性环氧树脂配置聚丙烯纤维混凝土,测试不同水性环氧树脂掺量的聚丙烯纤维混凝土的劈裂抗拉、抗折力学性能,进行了水性环氧树脂增强聚丙烯纤维的水泥附着性能试验和水性环氧树脂的不同掺量下增强聚丙烯纤维混凝土阻裂、抗渗性能效应试验,并对水性环氧树脂掺入聚丙烯纤维混凝土中后对各项性能的增强机理进行了探讨。以番禺大石大桥桥面铺装工程为例,介绍了水性环氧树脂掺入聚丙烯纤维混凝土的工程应用。     

低掺量水性环氧树脂对高性能混凝土抗冻耐久性的研究

用快冻法研究了低掺量水性环氧树脂乳液对高性能混凝土抗冻耐久性的影响。结果表明,水性环氧树脂乳液的加入可以显著提高混凝土的抗冻性。当乳液掺量为5%时,采用Ⅳ型养护制度养护得到的高性能混凝土的抗冻效果最好,在经历300次冻融循环后,相对动弹性模量可达94.1%;且水性环氧树脂能明显改善新拌混凝土的工作性,易于施工。     

双组分水性聚氨酯涂料的分散和成膜

研究了异氰酸酯低聚物在羟基组分中的分散、透明涂料和加颜填料涂料的成膜。由于异氰酸酯低聚物粘度高,必须有较高的剪切力才能保证其在羟基组分中的分散。透明涂料在混合后的反应是以异氰酸基与羟基的反应为主,而加颜填料涂料混合后的反应是以异氰酸基与水的反应为主。双组分水性聚氨酯涂料的成膜与溶剂型聚氨酯涂料及聚合物乳液涂料成膜机理不同,其可使用时间应以硬度或光泽度随时间变化来确定。     

聚丙烯酸酯共混改性水性聚氨酯乳液性能研究

自制水性聚氨酯乳液,并采用共混方法制备聚丙烯酸酯改性水性聚氨酯乳液。研究了共混改性涂膜的结构和性能,结果表明,聚丙烯酸酯共混改性水性聚氨酯乳液的涂膜性能比水性聚氨酯乳液涂膜性能有明显的提高。经过机械共混改性后,PU/PA膜的耐热性有了较大的提高,拉伸强度比PU膜大,而膜变硬、断裂伸长率大大降低。     

Microbiological Aspects of Water Quality and Health

Historically, typhoid and cholera are well-recognized waterborne infections. Advances in laboratory techniques over the past 20 years have enabled a wide range of other faccally-excreted bacteria, viruses and protozoa to be identified as causing gastrointestinal infections. Record outbreaks are referred to where some of these micro-organisms have been spread by the contamination of drinking water, either at source or during distribution. This has usually happened when the water was untreated, or where there have been failures of the disinfection process or breaches in the integrity of the distribution system. Recent waterborne outbreaks of cryptosporidiosis have underlined the importance of adequate filtration in the prevention of waterborne transmission of this protozoon, the oocysts of which are completely resistant to the levels of chlorine that can be attained in water treatment practice. An outline is given of the current processes by which pathogenic micro-organisms are excluded from drinking-water supplies; their potential deficiencies for dealing with some of the 'newer' waterborne pathogens are also discussed.     

阳离子型水性环氧树脂灌浆材料的研究

本文通过二烯丙基胺和二乙醇胺改性环氧树脂,分别在环氧树脂的一端引入双键,另一端引入亲水的羟基,再使用不饱和的有机酸中和,得到一种阳离子型的水性环氧树脂。以此水性环氧树脂为主剂,加入必要的辅剂制备的水性环氧树脂灌浆材料,使用水溶性氧化还原引发剂固化,得到性能良好的聚合物凝胶体。此种材料既有较好的强度,又有一定的韧性,且可在水中固化,避免使用大量的有机溶剂,是一种值得开发的多用途的新型水性环氧灌浆材料。     

I型水性环氧树脂固化剂及其涂料性能

采用低相对分子质量液体环氧树脂与非离子表面活性剂(BMJ)反应合成BMJ-环氧加成物,将表面活性链段引入到环氧树脂分子链中,然后经封端和成盐得到I型水性环氧固化剂.研究了影响I型水性环氧固化剂及其所配乳液涂料性能的因素,并对乳液的稳定性、固化速率和涂膜硬度等性能进行了评价.     

Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium hominis oocyst

Cryptosporidium parvum and Cryptosporidium hominis are obligate enteric protozoan parasites which infect the gastrointestinal tract of animals and humans. The mechanism(s) by which these parasites cause gastrointestinal distress in their hosts is not well understood. The risk of waterborne transmission of Cryptosporidium is a serious global issue in drinking water safety. Oocysts from these organisms are extremely robust, prevalent in source water supplies and capable of surviving in the environment for extended periods of time. Resistance to conventional water treatment by chlorination, lack of correlation with biological indicator microorganisms and the absence of adequate methods to detect the presence of infectious oocysts necessitates the development of consistent and effective means of parasite removal from the water supply. Additional research into improving water treatment and sewage treatment practices is needed, particularly in testing the efficiency of ozone in oocyst inactivation. Timely and efficient detection of infectious C. parvum and C. hominis oocysts in environmental samples requires the development of rapid and sensitive techniques for the concentration, purification and detection of these parasites. A major factor confounding proper detection remains the inability to adequately and efficiently concentrate oocysts from environmental samples, while limiting the presence of extraneous materials. Molecular-based techniques are the most promising methods for the sensitive and accurate detection of C. parvum and C. hominis. With the availability of numerous target sequences, RT-PCR will likely emerge as an important method to assess oocyst viability. In addition, a multiplex PCR for the simultaneous detection of C. parvum, C. hominis and other waterborne pathogens such as Giardia lamblia would greatly benefit the water industry and protect human health.     

水性聚氨酯树脂的合成和性质研究

通过对不同体系、不同配方下水性聚氨酯乳液及其涂膜的研究,发现了不同种类的二异氰酸酯、二元醇,不同含量的亲水单体、亲水基团以及改性单体、扩链剂、溶剂等对水性聚氨酯性能均有影响,得到适用于木器漆、皮革织物类涂层、防水涂料等的水性聚氨酯树脂。     

水性工业防腐涂料的制备研究

以水性环氧树脂为基料制备工业防腐涂料,分析讨论了水性环氧树脂乳液、水性环氧固化剂、颜填料以及各种助剂的选用对水性工业防腐涂料性能的影响,确定了水性环氧防腐涂料的配方和生产工艺。经工程应用表明,该产品防腐性能良好。     

水性环氧树脂在路面及桥面维修中的应用

介绍了水性环氧树脂的基本性能以及水性环氧树脂增强水泥混凝土各种性能指标的增强机理。以韶关翁源X347县道以及广东银盏至英德一级公路维修为工程实例,介绍了水性环氧树脂在路面及桥面铺装层维修中的应用,以供类似工程参考借鉴。     

水性环氧树脂纳米复合涂层材料制备与性能研究

水性环氧树脂涂层材料具有VOC含量低、气味小、施工安全等优势,且保留了环氧树脂对钢材和水泥附着力的优异。但目前水性环氧树脂涂层材料在耐侯性、耐磨性及耐水性等方面尚待提高。本工作采用纳米SiO2作为添加项,将超声波与高速分散机的物理作用与硅烷偶联剂的化学作用结合起来,使纳米粒子均匀分散于环氧树脂基体中,并通过溶液共混法制备出双组分水性环氧树脂纳米复合涂层材料。研究表明,纳米SiO2粒子的加入有效提高了水性环氧树脂的强度、韧性等综合力学性能以及耐候性和热稳定性,由此所制备的双组分水性环氧纳米复合涂层材料具有优良的耐水性、耐盐水、耐侯性且环保性能优异。该材料在水利水电工程中混凝土表面防水防护以及其他行业防水防腐蚀等领域都将具有良好的应用前景。     

Removal of Giardia and Cryptosporidium in drinking water treatment: a pilot-scale study

Giardia and Cryptosporidium have emerged as waterborne pathogens of concern for public health. The aim of this study is to examine both parasites in the water samples taken from three pilot-scale plant processes located in southern Taiwan, to upgrade the current facilities. Three processes include: conventional process without prechlorination (Process 1), conventional process plus ozonation and pellet softening (Process 2), and integrated membrane process (MF plus NF) followed conventional process (Process 3). The detection methods of both parasites are modified from USEPA Methods 1622 and 1623. Results indicated that coagulation, sedimentation and filtration removed the most percentage of both protozoan parasites. The pre-ozonation step can destruct both parasites, especially for Giardia cysts. The microfiltration systems can intercept Giardia cysts and Cryptosporidium oocysts completely. A significant correlation between water turbidity and Cryptosporidium oocysts was found in this study. The similar results were also found between three kinds of particles (phi=3-5,5-8 and 8-10 microm) and Cryptosporidium oocysts.     

Ⅱ型水性环氧树脂乳液及其固化过程的研究

先合成了含有环氧树脂基团和表面活性基团的反应性环氧树脂乳化剂,再用该乳化剂并借助于相反转技术制备Ⅱ型水性环氧树脂乳液,研究了乳化剂对水性环氧树脂乳液的稳定性,分散相粒径和固化性能的影响;研究了水性环氧树脂系统的成膜机理及其适有期。研究发现,乳化剂浓度合适时,所制得的乳液稳定性较好,分散相粒子的平均粒径较小,因而相应形成的兴膜是均匀,完全固化的硬膜,其硬度较高,水性环氧树脂体系的成膜机理与溶剂环氧树脂体系的成膜机理不同,其适用期应用涂膜光泽度随时间的变化来确定。     

水性丙烯酸胶黏剂中消泡剂消泡机理的研究

通过分析有机和分子级消泡剂在起泡液和水性丙烯酸胶黏剂乳液中的性能,考察了添加工艺和测试方法对消泡剂消泡性能的影响,探讨了消泡剂的消泡机理,综合选出了最适合水性丙烯酸胶黏剂乳液的消泡剂.结果表明:消泡剂的相容性和消泡能力成反比;在极短时间范围内,0.2%用量的消泡剂在起泡液中的动态吸附过程由扩散控制;分子级消泡剂适用于"架桥-铺展"机理,而有机消泡剂适用于"架桥-铺展"和"架桥-脱湿"机理;消泡剂的加入对水性丙烯酸胶黏剂乳液的黏度、粒径和存储稳定性无显著影响.     

水性涂料浅述

介绍了水性涂料的发展,指出水性涂料目前存在的主要问题。     

WEP改性泡沫沥青冷再生混合料的强度特性及耐久性

为提高泡沫沥青冷再生混合料的早期强度、抗松散性能、水稳定性和耐久性能,将水性环氧树脂(WEP)应用于泡沫沥青冷再生混合料,研究了WEP掺量对泡沫沥青冷再生混合料性能的影响,通过SEM分析了影响机理。结果表明,掺加WEP能显著提高泡沫沥青冷再生混合料的力学性能、水稳定性和抗疲劳耐久性能,同时降低疲劳寿命对应变水平的敏感性。WEP对泡沫沥青冷再生混合料的改性机理在于其界面增强作用、加箍锁作用及加筋阻裂作用。推荐泡沫沥青冷再生混合料中WEP的适宜掺量为2%~3%。     

Multi-scale Cryptosporidium/sand interactions in water treatment

Owing to its widespread occurrence in drinking water supplies and its significant resistance to environmental stresses, Cryptosporidium parvum is regarded as one of the most important waterborne microbial parasites. Accordingly, a substantial research effort has been aimed at elucidating the physical, chemical and biological factors controlling the transport and removal of Cryptosporidium oocysts in natural subsurface environments and drinking water treatment facilities. In this review, a multi-scale approach is taken to discuss the current state-of-knowledge on Cryptosporidium-sand interactions at a nano-scale, bench-scale and field-scale relevant to water treatment operations. Studies conducted at the nano-scale and bench-scale illustrate how techniques based on the principles of colloid and surface chemistry are providing new insights about oocyst-sand interactions during transport of Cryptosporidium oocysts in granular porous media. Specifically, atomic force microscopy and impinging jet experiments reveal the importance of oocyst surface biomolecules in controlling Cryptosporidium/sand interactions by a mechanism of steric hindrance. Traditional bench-scale column transport studies conducted over a broad range of experimental conditions highlight the role of physicochemical filtration and physical straining in the removal of oocysts from the pore fluid. Such experiments have also been used to evaluate the influence of biofilms formed on grain surfaces and the presence of natural organic matter on oocyst-sand interactions. Whilst filtration studies conducted at the plant-scale have been useful for evaluating the effectiveness of various materials as surrogates for Cryptosporidium oocysts, at this macro-scale, little could be learnt about the fundamental mechanisms controlling oocyst-sand interactions. This review of the literature on Cryptosporidium-sand interactions at different length scales points to the importance of combining studies at the plant-scale with well-controlled investigations conducted at the nano- and bench-scales. Furthermore, because oocyst surface properties play an important role in controlling the extent of interaction with sand surfaces, a thorough discussion of Cryptosporidium oocyst characteristics and electrical properties is presented.     

水性涂料中主要VOC成分研究

阐述了目前涂料中有害物质可能引发的健康危害。采用气相色谱质谱联用法测定了水性涂料中的VOC成分,主要包括乙二醇、2-氨基-2-甲基-1-丙醇和1,2-丙二醇等。介绍了这三种化学物质的性质、用途及健康毒性,提出了开展涂料中VOC健康危害研究的必要性。