二次供水系统中亚氯酸盐生成的影响因素

根据二次供水系统水质和水力条件的特点,采用二次消毒方式对消毒剂进行补充,研究了二氧化氯投加量、水力停留时间、生活给水的水温(8/20℃)、COD_(Mn)以及pH对二氧化氯和亚氯酸盐的影响,考察了生活热水的二氧化氯和亚氯酸盐的变化规律。结果表明,投加0.2 mg/L二氧化氯作为补充消毒剂时,二次供水的微生物指标可以满足水质的要求;降低二氧化氯投量、减少生活给水水力停留时间和生活热水的加热时间、控制二次供水的COD_(Mn)含量和pH,可有效降低亚氯酸盐的生成量。研究结果为二次供水系统中消毒剂补充投加与含量变化规律提供了依据,为保障二次供水系统的生物安全性和化学安全性提供了技术支持。     

二氧化氯与次氯酸钠联用降低亚氯酸盐生成量的应用研究

针对水厂采用二氧化氯消毒产生的亚氯酸盐超标问题，开展了以次氯酸钠替代二氧化氯消毒，同时保留二氧化氯预氧化，以降低制水过程二氧化氯投加量和亚氯酸盐生成量的试验。研究结果表明，二氧化氯与次氯酸钠联用不仅确保了消毒效果，而且使亚氯酸盐副产物浓度大幅度降低并稳定达标。     

用二氧化氯消毒饮用水

本文探讨二氧化氯替代游离氯对饮用水进行预处理的有效性。有关研究集中在三个方面：(1)使用二氧化氯后总三卤甲烷生成量下降幅度；(2)二氧化氯作为消毒剂的杀菌效果：(3)亚铁离子对二氧化氯有害氧化副产物的生成抑制作用。文献资料和实际应用表明。二氧化氯具有足够的消毒能力并可降低输配水系统内THMs的生成最，而且使输配水系统内总残余氧化剂(亚氯酸盐、氯酸盐和二氧化氯)等维持在低水平。     

二氧化氯消毒中水实验研究

研究了二氧化氯消毒中水COD与二氧化氯最小投加量的定量关系及确保二氧化氯持续消毒能力的剩余剂量。结果表明:在室温,COD为15~50 mg/L,浊度为1.00~6.37 NTU,大肠菌群数10~6数量级的条件下,中水COD与二氧化氯最小投加量定量关系满足一元线性方程。为保证二氧化氯的持续消毒能力,消毒30 min水样的剩余二氧化氯质量浓度不能低于0.10 mg/L。二氧化氯浓度随时间的衰减规律符合一级反应动力学模型,且随二氧化氯浓度的减小,其衰减速率逐渐减小。     

饮用水供水系统应用二氧化氯的卫生学问题

列出近年来有关替代在饮用水处理中使用的消毒剂氯的产品二氧化氯的文献。指出了使用二氧化氯比使用氯的优点。给出了二氧化氯及其使用时产生的副产物（亚氯酸盐和氯酸盐）的毒理学特性。     

有效控制水中消毒副产物氯酸盐和亚氯酸盐

某水厂采用二氧化氯对饮用水消毒,当出厂水二氧化氯为0.12mg/L时,按照《生活饮用水卫生标准》(GB5749-2006)评价,其氯酸盐和亚氯酸盐均超标。为了查明氯酸盐、亚氯酸盐超标原因,本论文对水厂的消毒工艺进行调整,实现水厂出厂水和管网水二氧化氯、氯酸盐和亚氯酸盐达标。     

二氧化氯与氯分步联合消毒减少饮水中亚氯酸盐的研究

二氧化氯和氯可以与水中有机物反应生成亚氯酸盐(CIO^-2)和三卤甲烷(THMs)和三卤乙酸(HAAs)等对人体有害的有机副产物。本研究采用二氧化氯和氯分步联合投加消毒武汉汉江水源水，结果表明，分步投加二氧化氯和氯的间隔时间约为30min，水样的pH为6时，联合消毒后水中CIO^-2的含量随着加氯量的增加逐渐减少，CIO^-2反应生成CIO^-2的转化率逐渐增高。     

顺序投加联合消毒剂二氧化氯-氯胺对饮用水中消毒副产物的控制

传统氯消毒工艺因易生成对人体有害的消毒副产物被广泛关注,采用替代氯消毒工艺控制消毒副产物是目前的研究重点。该文以天津市某自来水厂滤后水为试验对象,采用二氧化氯-氯胺顺序投加联合消毒工艺,分析了不同投加量组合对消毒副产物(THMs,HAAs和亚氯酸盐)产量的控制情况。结果表明当二氧化氯投加量为0.10~0.50 mg/L、氯胺投加量为0.50~1.50 mg/L时,消毒副产物的生成量均能得到有效控制,符合相关标准的要求。     

二氧化氯饮用水消毒剂的探讨

通过饮用水行业传统的氯系消毒剂的弊端和二氧化氯消毒剂在国内外的应用及其消毒原理和工艺过程的讨论 ,说明了二氧化氯消毒剂在净水消毒效果、使用的安全环保以及对人体的健康方面均优于氯系消毒剂。     

次氯酸钠与二氧化氯联用降低消毒副产物的应用探讨

为了解决自来水厂应用二氧化氯导致的消毒副产物亚氯酸盐、氯酸盐超标问题,对亚氯酸盐生成量与二氧化氯投加量相关性进行了测定分析,开展了以次氯酸钠替代二氧化氯消毒,同时保留二氧化氯预氧化生产性实验。结果表明,亚氯酸盐生成量与二氧化氯投加量显著相关,因此,采用二氧化氯预氧化与次氯酸盐消毒联用,既保证了水质消毒效果,又使水中亚氯酸盐的浓度大幅度降低并稳定达标。     

一种新的二氧化氯使用方法

通过加入一种水源性稳定剂 SI能使亚氯酸钠和固体酸在干燥状态下混合后不放出二氧化氯 ,将混合物加入水中又能迅速地产生二氧化氯 ,得到澄清透明的二氧化氯黄色水溶液 ,使用方便。     

Inorganic Reactions in Chlorine Dioxide Bleaching of Softwood Kraft Pulp

Abstract

A softwood kraft pulp (27 kappa) was bleached with chlorine dioxide to various end pH values. The formation of chlorite, chlorate, and chloride was measured to quantify the amount of chlorine dioxide wasted as a function of pH during a D_o (pre‐bleaching) stage. Chlorate formation increased with a decrease in final pH. Conversely, residual chlorite increased with an increase in the final pH. After 120 min of bleaching the total residual chlorite and chlorate showed that no substantial increase in residual oxidant occurs when bleaching to an end pH below 3.4. As a result, the brightness and permanganate numbers for low pH chlorine dioxide bleached pulps did not differ when bleaching to an end pH between 3.4 and 1.8. However, decreasing the pH below 3.4 did result in increased organic chloride formation. The results are contrary to previous studies where the maximum bleaching efficiency for a D₁ stage was reported to occur when the end pH was between 3 and 4.     

二氧化氯分析的研究进展

二氧化氯作为新一代杀菌消毒剂，在水处理中获得越来越广泛的应用。在应用中，二氧化氯会产生分解及歧化反应，产生副产物如Cl2、ClO^-、ClO2^-、ClO3^-，所以需要对残余ClO2及这些副产物进行分析，本文对二氧化氯现有的分析方法进行了讨论。     

二氧化氯分析的研究进展

二氧化氯作为新一代杀菌消毒剂，在水处理中应用日益广泛。在应用中，二氧化氯会发生分解及歧化反应，产生副产物如Cl2、ClO^-、ClO2^-、ClO3^-，所以需要对残余ClO2及副产物进行分析，该文对二氧化氯现有的分析方法进行了讨论。     

稳定性二氧化氯的制备与其稳定性的研究

稳定性二氧化氯是国际上公认的高效安全低毒消毒剂,有广泛的发展前景。本文主要研究了以亚氯酸钠为原料制备稳定性二氧化氯,探讨了加水量与稳定性二氧化氯浓度之间的关系,同时对稳定性二氧化氯的稳定性也进行了初步探讨,这对推广应用稳定性二氧化氯很有实用价值     

Mechanism and kinetics of chlorine dioxide reaction with hydrogen peroxide under acidic conditions

The reaction of chlorine dioxide with hydrogen peroxide was studied in a well stirred batch reactor in a pH range of 3.60 to 5.07, which is of interest for commercial chlorine dioxide bleaching of chemical pulp. The reaction rate was determined by following the consumption of chlorine dioxide and hydrogen peroxide and the formation of chlorite. The rate equation was established. It was found that the concentration dependencies of chlorine dioxide, hydrogen peroxide and hydroxide ion were all first-order. A reaction mechanism compatible with the rate equation was proposed. Since it was found in previous work that chlorite in chlorine dioxide solution by the addition of small amount of hydrogen peroxide potentially led to a decrease in the formation of organically bound chlorine during chlorine dioxide bleaching, two methods were suggested to implement this technique in a bleach plant.     

二氧化氯杀菌实验研究

以硫酸盐还原菌,铁细菌以及异养菌数为指标,考察了二氧化氯投加量,杀菌时间,温度及pH值几种影响因素以及余氯量随时间的变化。结果表明,在投加浓度为3mg/L,处理时间为90min时,杀菌率达98.33％,2h内余氯大于0．6mg/L。     

高稳定性二氧化氯片剂的研究

目前国内市场上固态二氧化氯释放剂技术不成熟,产品多为二元包装或伪一元包装,给使用和储存带来很多不便。为了解决这个问题,采取亚氯酸钠为释放剂主成分,辅以复合无机盐活化剂,借助小丸包衣技术和片剂工艺,制备了一元化、高纯、高稳定性二氧化氯片剂,具有较高的实际应用价值。     

Effects of the Preferential Oxidation of Phenolic Lignin Using Chlorine Dioxide on Pulp Bleaching Efficiency

Chlorine dioxide is widely used for pulp bleaching because of its high delignification selectivity. However, efficient and clean chlorine dioxide bleaching is limited by the complexity of the lignin structure. Herein, the oxidation reactions of phenolic (vanillyl alcohol) and non-phenolic (veratryl alcohol) lignin model species were modulated using chlorine dioxide. The effects of chlorine dioxide concentration, reaction temperature, and reaction time on the consumption rate of the model species were also investigated. The optimal consumption rate for the phenolic species was obtained at a chlorine dioxide concentration of 30 mmol·L⁻¹, a reaction temperature of 40 °C, and a reaction time of 10 min, resulting in the consumption of 96.3% of vanillyl alcohol. Its consumption remained essentially unchanged compared with that of traditional chlorine dioxide oxidation. However, the consumption rate of veratryl alcohol was significantly reduced from 78.0% to 17.3%. Additionally, the production of chlorobenzene via the chlorine dioxide oxidation of veratryl alcohol was inhibited. The structural changes in lignin before and after different treatments were analyzed. The overall structure of lignin remained stable during the optimization of the chlorine dioxide oxidation treatment. The signal intensities of several phenolic units were reduced. The effects of the selective oxidation of lignin by chlorine dioxide on the pulp properties were analyzed. Pulp viscosity significantly increased owing to the preferential oxidation of phenolic lignin by chlorine dioxide. The pollution load of bleached effluent was considerably reduced at similar pulp brightness levels. This study provides a new approach to chlorine dioxide bleaching. An efficient and clean bleaching process of the pulp was developed.