饮用水处理工艺中消毒副产物的变化特征研究

为阐明饮用水厂运行中主要消毒副产物的形成特征及转化规律,提出有效的控制措施,以北方某饮用水厂为研究对象,对采用预加氯的不同处理单元出水中3类消毒副产物,即8种卤乙酸(HAAs)、亚硝基二甲胺(NDMA)和4种三卤甲烷(THMs)的变化特征进行了研究。结果表明,经预氯化后3类副产物显著增加,HAAs、NDMA和THMs和质量浓度合计分别为33.1μg/L、9.0 ng/L和55.1μg/L;经双层滤料过滤后得到不同程度去除,5种可去除HAAs的去除率为15.7%～60.8%,NDMA去除率为48.1%,4种THMs的去除率为26.1%～49.2%。氯胺消毒下总出水中3类副产物含量也未明显增加,表明预氯化及氯胺消毒是进一步削减消毒副产物产生、降低饮用水健康安全风险的重要控制措施。     

饮用水氯化消毒产生三氯甲烷影响因素的研究

现代化学工业的迅速发展,尤其是合成化学工业的迅猛发展,使人类饮用水水源受到日益严重的污染.在饮用水处理工艺中,普遍采用的是混凝、沉淀、过滤和氯化消毒工艺,其主要功能是去除水中的悬浮固体和胶体以及杀灭菌类,但对水中大量的溶解性有机物无明显去除效果,而且在氯化消毒过程中,由于水中有机物质的氯化而形成了对人体健康危害更大的有机氯化物.1974年美国发现饮用水氯化消毒造成有致癌、致畸、致突变性三卤甲烷(THM)类物质,并将THM 类物质列入水中优先控     

高锰酸盐复合剂对三卤甲烷生成形态的影响

加氯消毒会产生具有致癌作用的三卤甲烷、卤乙酸等消毒副产物，环境化学和环境医学的近期研究证实大部分消毒副产物都具有致癌作用。为了提供安全放心的饮用水，人们开发了各种技术来实现对消毒副产物的控制，投加氧化剂就是一种非常有效的手段。在常用的氧化剂中，高锰酸盐复合剂（PPC）具有优良除污染效能，在强化混凝、强化除浊、去除有机污染物、去除铁锰、去除藻类及臭味等方面具有非常良好效果，高锰酸盐复合剂预氧化取代预氯化可以明显降低出水中三卤甲烷（THMs）的生成量。     

氯化消毒副产物及二氧化氯消毒剂的应用

介绍了水中微量有机污染物种类，包括饮用水中有机污染物、大分子天然有机物、氯化消毒副产物和藻类及其代谢产物。常规给水处理工艺消毒副产物及对饮用水水质影响。并介绍了二氧化氯作为消毒剂的研究现状及其消毒副产物的去除。     

饮用水消毒副产物生物毒性与调控策略的研究

饮用水消毒可以有效除去病毒、细菌等有害微生物,但消毒剂会与水中的有机物反应生成多种消毒副产物(DBPs),危害人类健康。基于对消毒副产物种类、生成及污染现状的探讨,归纳总结了DBPs的典型生物毒性及其毒性作用机制。为有效防控DBPs环境风险,深入探讨了针对去除DBPs前体物、优化消毒剂及消毒过程、DBPs毒性的调控策略。最后对DBPs生物毒性作用机制及调控策略的研究进行了展望,为DBPs污染防治提供理论与技术支持。     

水厂预臭氧化处理过程中消毒副产物的变化研究

以滦河水为处理对象,对天津市某水厂预臭氧化-紫外+氯联合消毒工艺处理过程中的氯化消毒副产物和臭氧副产物的变化情况进行了分析研究。分别对各处理单元出水中的三卤甲烷生成势(THMFP)、卤乙酸生成势(HAAFP)、甲醛、溴酸盐的含量进行检测。结果表明,原水经过预臭氧化处理后,THMFP和HAAFP的质量浓度均有降低,预臭氧处理单元对THMFP和HAAFP的平均去除率分别为22.76%和22.38%;整套工艺对THMFP和HAAFP的平均去除率分别可达46.23%和55.38%。经预臭氧化处理后,甲醛的浓度上升,但后续工艺对甲醛的去除效果较好,未出现溴酸盐超标。     

水处理组合消毒方式分析

消毒的主要目的是为了灭活水中的致病微生物。水厂中主要被使用的消毒剂有氯、氯胺、臭氧、二氧化氯和紫外线。综合分析其消毒效巢和优缺点。重点介绍了多种组合消毒方式,以及分析其在水厂消毒中改善消毒效果和控制消毒副产物方面的应用。     

高锰酸钾预氧化—O3/BAC组合工艺处理长江陈行水库原水

以长江陈行水库原水为研究对象,探讨高锰酸钾预氧化-O3/BAC组合工艺对水中有机物、消毒副产物前驱物的去除效果,并评价该工艺出水生物稳定性。结果表明,生物活性炭出水CODMn均值为0.63 mg.L-1,平均去除率68.9%,UV254均值为0.005 cm-1,平均去除率89.0%;高锰酸钾预氧化-O3/BAC组合工艺可以有效去除水中氯化消毒副产物前驱物,对THMFP和HAAFP的去除率分别为66.2%和84.2%;该工艺出水AOC质量浓度为47μg.L-1,,生物稳性较好。     

饮用水中消毒副产物的形成机理与控制技术研究

饮用水中消毒副产物主要存在形式为三卤甲烷类和卤乙酸类有机物。对饮用水中消毒副产物的形成机理及目前控制饮用水中消毒副产物的方法和特点进行了论述     

家庭常用处理方法控制氯化消毒饮用水中消毒副产物的研究进展

饮用水消毒可有效去除水中病原微生物,但氯消毒剂可与水中的有机物、溴碘离子反应,在水处理厂和输水管网系统中持续生成对人体健康具有潜在危害的消毒副产物(DBPs).家庭水处理方法是饮用水进入人体前的最后一道防线,可减少水中DBPs的含量及其对人体健康带来的不良影响,进一步确保饮水安全.文中对家庭常用的饮用水处理方法(烹煮操...     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。