Stable hydrogen,carbon and chlorine isotope measurements of selected chlorinated organic solvents

Stable hydrogen isotopes of two chlorinated solvents, trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA), provided by five different manufacturers, were determined and compared to their carbon and chlorine isotopic signatures. The isotope ratio for delta2H of different TCEs ranged between +466.9 per thousand and +681.9 per thousand, for delta13C between -31.57 per thousand and -27.37 per thousand, and for delta37Cl between -3.19 per thousand and +3.90 per thousand. In the case of the TCAs, the isotope ratio for delta2H ranged between -23.1 per thousand and +15.1 per thousand, for delta13C between -27.39 per thousand and -25.84 per thousand, and for delta37Cl between -3.54 per thousand and +1.39 per thousand. As well, a column experiment was carried out to dechlorinate tetrachloroethylene (PCE) to TCE using iron. The dechlorination products have completely different hydrogen isotope ratios than the manufactured TCEs. Compared to the positive values of delta2H in manufactured TCEs (between +466.9 per thousand and +681.9 per thousand), the dechlorinated products had a very depleted delta2H (less than -300 per thousand). This finding has strong implications for distinguishing dechlorination products (PCE to TCE) from manufactured TCE. In addition, the results of this study show the potential of combining 2H/1H analyses with 13C/12C and 37Cl/35Cl for isotopic fingerprinting applications in organic contaminant hydrogeology.     

一种三元复合型细水雾洗消氯气的性能及机理研究

采用由亚铁（Fe^2＋）盐、表面活性剂（OP）和清水组成的三元复合型洗消剂对液氯泄漏进行模拟洗消实验研究,其洗消效率比清水细水雾有显著提高。通过对比实验考察了添加剂的浓度和洗消时间对其洗消效率的影响,并对雾滴粒径进行了测量。研究结果表明洗消剂中各成分之间的物理化学耦合作用提高了含添加剂的细水雾的洗消效率,表面活性剂组分可以降低溶液的表面张力,减小雾滴粒径,增大细水雾与氯气的接触面积;而亚铁盐组分则可以与氯气发生化学反应,将强氧化性的Cl2完全转变为较稳定的Cl-,增强洗消剂的化学洗消作用,且洗消效果更加彻底。     

饮用水氯化消毒过程的动力学模型研究进展

饮用水氯化消毒的安全性问题一直是水处理领域的研究重点,其氯化消毒过程动力学过程模型的建立,对于饮用水含氯量监测、评价及生成消毒副产物的控制具有重要意义。本文概述了饮用水氯化消毒过程的有关动力学模型研究现状及进展,从模型依据的机理和表达形式等方面分析了饮用水氯化消毒过程的动力学模型研究进展,介绍了广泛应用的几种模型,如Clark自由氯衰减模型、Valentine氯胺衰减模型等,通过对相关模型的原理、异同点、优缺点、适用性的对比及对影响模型的因素分析,对氯化消毒过程中动力学模型的今后发展趋势作了展望。     

利用二氧化氯复合消毒剂处理医院污水

在实验研究基础上,成功利用二氧化氯复合消毒剂处理医院污水。处理结果证明该工艺具有处理效果好、运行稳定、费用低、可操作性强等优点。     

Effects of reductive inorganics and NOM on the formation of chlorite in the chlorine dioxide disinfection of drinking water

Chlorine dioxide (ClO₂) disinfection usually does not produce halogenated disinfection by-products, but the formation of the inorganic by-product chlorite (ClO₂^–) is a serious consideration. In this study, the ClO₂^– formation rule in the ClO₂ disinfection of drinking water was investigated in the presence of three representative reductive inorganics and four natural organic matters (NOMs), respectively. Fe²⁺ and S^2– mainly reduced ClO₂ to ClO₂^– at low concentrations. When ClO₂ was consumed, the ClO₂^– would be further reduced by Fe²⁺ and S^2–, leading to the decrease of ClO₂^–. The reaction efficiency of Mn²⁺ with ClO₂ was lower than that of Fe²⁺ and S^2–. It might be the case that MnO₂ generated by the reaction between Mn²⁺ and ClO₂ had adsorption and catalytic oxidation on Mn²⁺. However, Mn²⁺ would not reduce ClO₂^–. Among the four NOMs, humic acid and fulvic acid reacted with ClO₂ actively, followed by bovine serum albumin, while sodium alginate had almost no reaction with ClO₂. The maximum ClO₂^– yields of reductive inorganics (70%) was higher than that of NOM (around 60%). The lower the concentration of reductive substances, the more ClO₂^– could be produced by per unit concentration of reductive substances. The results of the actual water samples showed that both reductive inorganics and NOM played an important role in the formation of ClO₂^– in disinfection.     

长江口地区的盐水入侵灾害及变化趋势

本文在总结长江口地区现状盐水入侵时空变化规律的基础上,着重分析了在未来海平面上升、长江东线南水北调和三峡水利枢纽工程以及长江口北支综合整治等因素影响下,南支河段盐水入侵强度的变化趋势。     

二氧化氯在环境中的应用

本文在总结二氧化氯的各种特性的基础上,评细讨论了二氧化氯作为氧化剂,消毒杀菌剂,除臭剂在环境中的应用及其机理。指出了二氧化氯在环境中进一步应用的潜力。     

城市污水厂二级生物处理出水氯消毒影响因素研究

进行了城市污水厂二级生物处理出水氯消毒影响因素研究,结果表明:对次氯酸钠,二氧化氯消毒效果影响最大的是pH,其次是有机氮,COD,氨氮的影响相对较小。运用Selleck-Collins公式对数据进行分析。     

二氧化氯的稳定和活化方法研究

采用 Na2 CO3和 H2 O2 作为 Cl O2 的稳定剂并得出最佳配比为 2∶ 3 (摩尔比 ) ,以醋酸、盐酸和柠檬酸作为活化剂进行活化试验 ,得到活化剂用量和活化时间对活化浓度的关系。     

高氯离子废水COD的吸收测定方法探讨

本法基于可定量测定K2Cr2O7和Cl-的反应产物Cl2这一原理,在用吸收装置吸收Cl2后,用碘量法测定余氯,从而消除氯离子的干扰.本法具有较高的准确度和精密度.