二氧化钛光催化氧化杀菌的研究及进展

本文概括了光催化氧化杀菌的发展历史，以及最新的研究进展，综合分析了其杀菌机理和影响反应的各相关因素，并为今后的发展提出了一些看法。     

带长链烷基季铵盐杀菌活性官能团树脂的合成

以强酸型阳离子交换树脂作载体 ,合成磺酰氯树脂后固载乙二胺并胺基叔胺化 ,最后加卤代烷合成带长链烷基季铵盐杀菌活性官能团树脂 ,确定了合成路线中的各步反应条件。对异养菌的杀菌性能测定结果表明 ,合成的杀菌树脂的杀菌率在测定条件下都达到了 90 %以上 ,有望用于工业和民用水的杀菌消毒     

二氧化钛载银抗菌剂的研究进展

介绍了二氧化钛系和银系无机抗菌剂在国内外的研究现状、杀菌机理以及存在的问题,论述了二氧化钛载银改性杀菌材料的最新进展,并就其研究开发亟需解决的关键问题提出了可行性建议。     

紫外联合过硫酸盐杀灭水中大肠杆菌

为提高UV杀菌效率并同时解决UV杀菌存在光复活现象的问题,以大肠杆菌为研究对象,采用UV-PS(紫外联合过硫酸盐)体系杀灭水中大肠杆菌,研究了各因素对UV-PS体系杀菌效果的影响,并考察复活光强度(0～42μW·cm~(-2))对不同体系处理后大肠杆菌复活的影响,最后分析其杀菌机理。结果表明:UV-PS体系杀菌效率高于单独UV及单独PS杀菌,15 mJ·cm~(-2)紫外剂量下,0.3 mmol·L-1 PS的加入较单独UV杀菌时大肠杆菌对数去除率增加1.0个对数级;且一定范围内大肠杆菌对数去除率随着PS初始浓度的增加而增加;中性条件更有利于大肠杆菌杀灭;Fe2+对大肠杆菌杀灭产生抑制效果;大肠杆菌经UV-PS体系处理后光复活能力明显下降,且仅在较强的复活光照下才会产生一定的光复活;UV-PS体系较单独UV杀菌时大肠杆菌细胞形态破坏更为严重,UV-PS体系产生的硫酸根自由基首先攻击细胞表面,使得细胞结构破损,细胞膜破裂,进而对其内容物进行氧化损伤,导致细胞死亡。UV-PS体系杀菌效率高且对大肠杆菌的光复活现象抑制明显,具有一定的应用前景。     

带长链烷基季铵盐杀菌活性官能团树脂的合成

以强酸型阳离子交换树脂作载体，合成磺酰氯树脂后固载乙二胺并胺基叔胺化，最后加卤代烷合成带长链烷基季铵盐杀菌活性官能团树脂，确定了合成路线中的各步反应条件。对异养菌的杀菌性能测定结果表明，合成的杀菌树脂的杀菌率在测定条件下都达到了90%以上，有望用于工业和民用水的杀菌消毒。     

气体二氧化氯对图书馆空间环境的消毒研究

选用高纯气体二氧化氯作为杀菌消毒剂,以中北大学图书馆阅览室作为研究对象,采用五点梅花法对空气中细菌进行采样,平板涂布法对采集到的细菌进行计数.通过研究不同气体二氧化氯浓度和杀菌时间条件下,气体二氧化氯对图书馆阅览室的杀菌效果,得出气体二氧化氯在低浓度下灭活细菌的最佳条件,即气体二氧化氯质量浓度为0.3 mg/m3、杀菌...     

原位电化学杀菌技术处理循环冷却水

分别以金属氧化电极和不锈钢为阳极和阴极,在恒电流模式下,考察了电流密度、停留时间、放置时间、极间距和稀释比等因素对电厂循环冷却水杀菌效果的影响。实际现场结果表明,针对电厂循环冷却水,电化学杀菌处理是行之有效的,电流密度、停留时间、极间距、稀释比对杀菌效果影响较大;在电流密度120 A/m2、停留时间10 s、极间距1.8 cm的条件下,杀菌效果可以达到97%;在一定实验条件下及一定放置时间内,经处理后的循环冷却水异氧菌总数能得到有效抑制。     

二氧化钛载银抗菌剂的研究进展

介绍了二氧化钛系和银系无机抗菌剂在国内外的研究现状、杀菌机理以及存在的问题，论述了二氧化钛载银改性杀菌材料的最新进展，并就其研究开发亟需解决的关键问题提出了可行性建议。     

低温等离子体杀菌的实验研究

由于传统的化学水处理方式有化学成分残留和环境污染问题，因而迫切需要开发新型的水处理技术。本研究针对现有杀菌消毒方法的不足之处，利用低温等离子体进行杀菌处理的实验研究，对电压、水层厚度、气体种类及电极形式的影响进行考察。结果表明，低温等离子体用于杀菌不仅效果显著，而且使用方便、快捷、安全并无残留，因而适于饮用水或者生活污水的杀菌处理。     

高压静电杀菌灭藻技术研究

高压静电场处理水伴随其电导率、溶解氧、pH值等物理化学参数的变化具有显著的杀菌灭藻效果。指出其杀菌灭藻机理，是超氧阴离子自由基、过氧化氢破坏了细胞的生存条件所致。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

Evaluation of the presence of drugs of abuse in tap waters

A total of seventy samples of drinking water were tested for non-controlled and illicit drugs. Of these, 43 were from Spanish cities, 15 from seven other European countries, three from Japan and nine from seven different Latin American countries. The most frequently detected compounds were caffeine, nicotine, cotinine, cocaine and its metabolite benzoylecgonine, methadone and its metabolite EDDP. The mean concentrations of non-controlled drugs were: for caffeine 50 and 19 ng L⁻¹, in Spanish and worldwide drinking water respectively and for nicotine 13 and 19 ng L⁻¹. Illicit drugs were sparsely present and usually at ultratrace level (<1 ng L⁻¹). For example, cocaine has mean values of 0.4 (Spain) and 0.3 ng L⁻¹ (worldwide), whereas for benzoylecgonine, these mean values were 0.4 and 1.8 ng L⁻¹, respectively. Higher concentrations of benzoylecgonine were found in Latin American samples (up to 15 ng L⁻¹). No opiates were identified in any sample but the presence of methadone and EDDP was frequently detected. Total mean values for EDDP were 0.4 ng L⁻¹ (Spain) and 0.3 ng L⁻¹ (worldwide). Very few samples tested positive for amphetamines, in line with the reactivity of chlorine with these compounds. No cannabinoids, LSD, ketamine, fentanyl and PCP were detected.     

Mechanisms of biodegradation of dibenzoate plasticizers

Biodegradation mechanisms were elucidated for three dibenzoate plasticizers: diethylene glycol dibenzoate (D(EG)DB), dipropylene glycol dibenzoate (D(PG)DB), both of which are commercially available, and 1,6-hexanediol dibenzoate, a potential green plasticizer. Degradation studies were done using Rhodococcus rhodochrous in the presence of pure alkanes as a co-substrate. As expected, the first degradation step for all of these systems was the hydrolysis of one ester bond with the release of benzoic acid and a monoester. Subsequent biodegradation of the monobenzoates of diethylene glycol (D(EG)MB) and dipropylene glycol (D(PG)MB) was very slow, leading to significant accumulation of these monoesters. In contrast, 1,6-hexanediol monobenzoate was quickly degraded and characterization of the metabolites indicated that the biodegradation proceeded by way of the oxidation of the alcohol group to generate 6-(benzoyloxy) hexanoic acid followed by β-oxidation steps. This pathway was blocked for D(EG)MB and D(PG)MB by the presence of an ether function.The use of a pure hydrocarbon as a co-substrate resulted in the formation of another class of metabolites; namely the esters of the alcohols formed by the oxidation of the alkanes and the benzoic acid released by hydrolysis of the original diesters. These metabolites were biodegraded without the accumulation of any intermediates.     

混凝试验搅拌器的研制

影响混凝效果的因素众多,混凝沉淀烧杯试验是进行水的混合、絮凝、沉淀工艺研究、设计和生产指导的最有效方法之一,阐述了智能型混凝试验搅拌器的设计原理和技术性能.     

不同泥源对厌氧氨氧化反应器启动的影响

采用2套上流式生物膜反应器,分别接种少量厌氧氨氧化污泥和大量硝化污泥,考察其对厌氧氨氧化反应器启动的影响。污泥接种入反应器后,测得接种厌氧氨氧化污泥的反应器(R1)内MLSS为0.22 g/L,另一个反应器(R2)MLSS为2.7 g/L。与直接接种厌氧氨氧化污泥相比,R1经过72 d的运行才显现出厌氧氨氧化特性。经过114 d的培养,前者氮去除速率由0.23 kg/(m3.d)提升到5.29 kg/(m3.d),总氮去除率大于89%;R2的氮去除速率由0.01 kg/(m3.d)提升到1.1 kg/(m3.d),总氮去除率大于84.6%。说明普通污泥启动需要一个较长的筛选过程,直接接种少量的厌氧氨氧化污泥比接种普通的污泥能够更快启动厌氧氨氧化反应器。     

生物质快速热裂解主要参数对生物油产率的影响

以松木木屑为原料,在自制的小型流化床上,开展了生物质热裂解温度、生物质粒径和进料速率对生物油产率的影响实验研究.结果表明,在热裂解温度分别为450、475、500、525和550℃条件下,当热裂解温度为500℃时,生物油产率最高,平均产率达到53.33%（质量百分比）.反应温度越高,炭产量越低,不可冷凝气体产量越高,气体发热值越高;粒径＜1 mm的生物质其粒径对生物油产率影响不大;生物质进料速率增加时,生物油产率增加.本研究为生物能的利用提供了新的途径.     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

造纸废水混凝处理中SFT助凝替代性研究

中小造纸厂废水处理常用PAC作混凝剂 ,PAM作助凝剂。由于PAM成本很高 ,影响了处理设备的投运率。用超细滑石粉 (SFT)替代PAM助凝 ,与混凝剂PAC配合 ,其混凝处理效果基本相当 ,但是处理成本降低 0 .10元 /m3 。由于SFT属环境无害材料 ,不会给排泥带来二次污染     

产油微藻培养与回收的关键技术研究进展

寻找廉价而高效的替代原料是实现生物柴油产业化的关键所在.微藻以含油量高、生长周期短、环境适应能力强、生物产量高等优点,有望成为一种极具潜力的生物柴油生产原料.然而,目前尚存在微藻培养低效成本高和微藻回收效率低两大难题.综述了微藻培养与回收过程中的关键技术,并对存在的两大难题及其改进技术进行了详细的探讨.最后,总结并展望了微藻培养、回收技术未来的发展趋势.