基于高纯二氧化氯消毒的水中无机副产物转化机制研究

发布时间：2018-03-17 18:12

本文选题：二氧化氯　切入点：消毒副产物　出处：《哈尔滨工业大学》2016年博士论文　论文类型：学位论文

【摘要】：我国《生活饮用水卫生标准》GB5749-2006规定二氧化氯可作为饮用水消毒剂,但其在消毒过程中所产生的无机消毒副产物,对人类健康存在潜在的危害。在二氧化氯消毒剂的使用过程中,确保其消毒效果,保证消毒副产物不超标是目前水厂关注的重点。而在饮用水输送过程中,管网对水质产生影响因素众多,系统分析饮用水流经管网过程中消毒副产物的浓度变化及相关影响因素与机制,进而帮助二氧化氯投加量的精确调控是本文的研究目的。通过评估水中含氯化合物的检测技术,阐明了显色剂DPD的动力学的区分效果最好,响应时间为30s,加标回收率98.5%;掩蔽剂EDTA的响应时间最短(50s),标准偏差0.02mg/L。采用上述检测方法,分析了实际水厂的二氧化氯及其消毒副产物分布特征。认为高纯二氧化氯消毒的供水管网中产生的主要副产物是亚氯酸盐,不同季节的管网中二氧化氯和亚氯酸盐的浓度都呈现转化趋势,且管网中的管垢存积会对亚氯酸盐产生影响。对实际管网水中消毒副产物浓度进行分析,得到亚氯酸盐转化率为22.6%。在此发现基础上,为了阐明基于高纯二氧化氯消毒的供水管网中亚氯酸盐转化的原因,通过研究二氧化氯衰减的影响因素,发现二氧化氯的衰减速率在铸铁管网中最高,PVC管最低;二氧化氯初始浓度与其衰减速率呈负相关趋势;温度和水流速度与二氧化氯衰减速率呈正相关趋势;二氧化氯的衰减符合一级反应动力学。通过分析供水管网中水相因素对消毒副产物转化的作用,表明二氧化氯的主要消毒副产物,亚氯酸盐的转化受游离二氧化氯浓度、管网材质、亚铁离子和零价铁浓度的影响。分析亚氯酸盐转化的关键影响因素,结果表明0.05mg/L Fe2+、0.3mg/L Fe0、0.5mg/L Cl O2、p H 7.0、20℃的条件最符合实际管网转化环境,转化率为1.2%。为了分析供水管网中固相因素对亚氯酸盐转化的作用,探讨了管垢吸附消毒副产物的影响因素。采用吸附动力学二级模型、颗粒内扩散模型和吸附热力学Freundlich模型拟合分析,说明管垢吸附是以化学吸附为主,其中颗粒内扩散是影响吸附速率的限速步骤之一。通过热力学平衡分析,阐明了管垢吸附Δ?00,是自发进行的吸附。同时,采用X荧光光谱分析(WDXRF)、X射线衍射分析(XRD)、X射线光电子能谱分析(XPS)等分析仪器对管垢吸附亚氯酸盐前后的组分进行分析,结果表明管垢吸附后增加的氯元素价态主要为-1价,从理论与实验两个水平上解释了管垢吸附消毒副产物的影响因素及吸附行为。最后在以上研究基础上,构建了消毒副产物的吸附模型,并运用响应曲面分析技术进行优化。建立了亚氯酸盐的管垢吸附模型为η=212.40+37.35C_o-48.23pH+2.75T-6.00C_opH~2-0.07T~2。运用模型及优化条件预测了管垢吸附亚氯酸盐的转化率,为16.8%。结合化学转化率1.2%,预测管网中亚氯酸盐的总转化率为18.0%,与管网调查中获得的转化率22.6%接近。参照我国《生活饮用水卫生标准》,按照理论转化率95-98%计算,二氧化氯的最大实际投加量为1.14-1.18 mg/L。基于高纯二氧化氯消毒的地下水中,按照国际上最严格的标准,亚氯酸盐允许浓度不超过0.2mg/L,计算得到二氧化氯的理论投加量增加0.04mg/L时仍然符合标准;按照我国的标准,亚氯酸盐允许浓度不超过0.7mg/L,计算得到二氧化氯的理论投加量增加0.18mg/L时仍然符合国家标准。综上所述,本论文通过研究高纯二氧化氯消毒的给水管网中消毒副产物亚氯酸盐的转化机制,对实际使用中二氧化氯投加量的精确调控提供了帮助与理论依据,有助于实现从安全用水到健康用水的新局面。
[Abstract]:>GB5749-2006 sanitary standard for drinking water in China "can be used as drinking water regulations of chlorine dioxide disinfectant, but inorganic disinfection by-products generated in the process of disinfection, the potential harm to human health. In the process of using chlorine dioxide disinfectant, ensure the disinfection effect, ensure the disinfection by-products does not exceed the standard is the focus of attention in current while drinking water. In the transport process, the pipeline network to quality factors, system factors and mechanism analysis of concentration of disinfection by-products in drinking water management process and related effects, precise control and help of chlorine dioxide dosage is the purpose of this study. By evaluating the water detection technology of chlorinated compounds that illustrates the dynamics of chromogenic agent DPD to distinguish the best effect, the response time is 30s, the recovery rate of 98.5%; the response time of the masking agent EDTA (50s), marking the shortest The standard deviation of the 0.02mg/L. detection method, analyzed the distribution characteristics of disinfection by-products of chlorine dioxide and its actual water. That the main by-product of high purity chlorine dioxide in the water supply network is chlorite, the concentration of network in different seasons of chlorine dioxide and chlorite are transformation trend, and pipe scale in the network storage product will have an impact on chlorite. The actual pipe network water disinfection by-products concentration analysis, get the chlorite conversion rate is 22.6%. on the basis of this, in order to clarify the reason of high purity chlorine dioxide disinfection of water supply network based on the transformation of the chlorite, factors according to the influence of chlorine dioxide decay, found the highest rate in the cast iron pipe in the decay of chlorine dioxide, PVC minimum; chlorine dioxide concentration and initial decay rate was negatively correlated; temperature and flow rate and two The oxidation of chlorine decay rate was positively correlated; the decay of chlorine dioxide followed first-order kinetics. Through the analysis of water supply networks of water phase factors on Transformation of disinfection by-products of chlorine dioxide disinfection, showed that the main by-products, conversion of chlorite by free chlorine dioxide, pipeline material, effects of ferrous ion and zero valent iron concentration. Analysis of key factors influencing chlorite conversion, the results show that 0.05mg/L Fe2+, 0.3mg/L Fe0,0.5mg/L Cl O2, P H 7.0,20 DEG C is the most realistic network environment for the transformation, the conversion rate of 1.2%. in order to analyze the factors of water supply network in solid phase transformation of chlorite, and discusses the factors affecting the adsorption pipe scale disinfection by-products. The adsorption kinetics of two level model, analysis model and the adsorption thermodynamics of Freundlich particle diffusion model fitting, illustrate the pipe scale adsorption is mainly chemical adsorption, the In the intra particle diffusion is one of the rate limiting step of the adsorption rate. The thermodynamic equilibrium analysis, the pipe scale is 00, the adsorption was spontaneous? Adsorption. At the same time, the analysis of fluorescence spectra of X (WDXRF), X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) analysis instrument the pipe scale before and after adsorption of chlorite were analyzed, results showed that chlorine pipe scale after adsorption increased valence is mainly -1 price, explains the factors and influence the adsorption behavior of pipe scale adsorption disinfection by-products from the two levels of theory and experiment. Finally based on the above research, the construction of adsorption the model of disinfection by-products, and the use of response surface analysis techniques were optimized. A pipe scale adsorption model of chlorite as the model and the optimization conditions of =212.40+37.35C_o-48.23pH+2.75T-6.00C_opH~2-0.07T~2. by ETA predicted chlorite adsorption pipe scale Salt conversion rate, 16.8%. combined with chemical conversion rate of 1.2%, the total conversion prediction network chlorite rate was 18%, 22.6% and close to the conversion rate of the network investigation. According to "our drinking water health standards", in accordance with the theory of computing the conversion rate of 95-98%, the actual chlorine dioxide dosage is 1.14-1.18 mg/L. underground water of high purity chlorine dioxide disinfection based on in accordance with the most stringent standards, chlorite allowable concentration is less than 0.2mg/L, calculated by the theory of chlorine dioxide dosage still conforms to the standard of 0.04mg/L increase; in accordance with the standard of our country, the chlorite allowable concentration does not exceed 0.7mg/L, calculated by the theory of adding chlorine dioxide increase the amount of 0.18mg/L is still in line with national standards. In summary, this paper through the transformation mechanism of water supply pipe network of high purity chlorine dioxide disinfection disinfection by-products in the chlorite, on The accurate control of the dosage of chlorine dioxide in actual use provides a help and theoretical basis, and helps to realize a new situation from safe water to healthy water.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R123.6

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