【作者】 张立珠；

【导师】 马军；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2008， 博士

【摘要】 我国饮用水源污染严重,特别是有机污染物,如果不能在混凝过程中去除,在后续的消毒过程中可能会与氯作用生成毒害更强的消毒副产物,对人体健康构成威胁。因此,混凝过程是保障饮用水安全的一个重要过程。但常规混凝剂及混凝方法对有机污染物去除效果有限,难以达到新颁布的生活饮用水卫生标准的要求。因此,开发高效、廉价、使用方便及不存在二次污染的多功能混凝剂具有重要意义。本文通过对新生态二氧化锰与有机物间的作用特性及机理研究,旨在为饮用水处理提供一种经济简便的除污染方法。在中性pH条件下,采用硫酸锰与高锰酸钾在线投加的方式制备新生态二氧化锰,通过原子力显微镜、红外光谱及比表面积等分析手段对新生态二氧化锰的微观结构形态进行了表征。结果表明,新生态二氧化锰颗粒呈现不规则的球形,粒径小于100nm,颗粒产生瞬间即发生凝聚。新生态二氧化锰表面富含羟基,比表面积大。通过研究新生态二氧化锰与苯酚的反应规律,发现溶液pH影响新生态二氧化锰与还原性有机物的作用。在中性pH条件下新生态二氧化锰与苯酚间主要发生吸附作用,而在强酸性条件新生态二氧化锰与苯酚发生氧化还原反应,苯酚的去除率也明显提高,但新生态二氧化锰不能将苯酚彻底氧化,会生成苯醌和联苯酚等中间产物。以新生态二氧化锰为吸附剂,以苯胺、苯酚、硝基苯和苯甲酸四种有机物为目标物,研究新生态二氧化锰对这些有机物的吸附性能和作用机理。结果表明,新生态二氧化锰对所选择的四种有机物的吸附能力为:苯胺>苯酚>硝基苯>苯甲酸。通过对有机物分子结构的比较,正负离子对新生态二氧化锰吸附效能的影响分析,发现新生态二氧化锰的比表面积及静电作用对其吸附作用有重要影响。一般情况下,新生态二氧化锰的比表面积越大,其对有机物的吸附能力越强,新生态二氧化锰更易于吸附带正电荷的有机物;有机物的疏水作用次之,有机物的疏水性越强,有利于其在新生态二氧化锰表面吸附。新生态二氧化锰对有机物的吸附更符合Langmuir吸附等温模型。以新生态二氧化锰作为混凝剂和助凝剂,考察新生态二氧化锰对微污染水中有机物的去除效能,并考察混凝条件对其混凝效果的影响。结果表明,新生态二氧化锰具有较好的有机物去除能力,如投加10mg·L-1二氧化锰,UV254的去除率约为40%以上,TOC的去除率接近20%。新生态二氧化锰混凝去除有机物的速率非常快,有机物的去除主要发生在混凝过程的快速搅拌阶段。而将新生态二氧化锰作为助凝剂投加(投量0.3 mg·L-1),强化硫酸铝混凝作用,UV254和TOC的去除率能够提高20%以上。以单宁酸作为天然有机物的代表,研究新生态二氧化锰对大分子有机酸的去除效能及新生态二氧化锰在高锰酸钾强化混凝去除天然有机物中的作用规律。结果表明,与苯甲酸不同,新生态二氧化锰对单宁酸具有较好的吸附去除效能,而且钙离子能够促进新生态二氧化锰对单宁酸的吸附作用,说明有机酸的分子量对新生态二氧化锰的吸附作用有影响。高锰酸钾对单宁酸的氧化作用不是单宁酸去除的主要因素,新生态二氧化锰吸附才是单宁酸去除的主要作用。新生态二氧化锰对松花江微污染水的混凝试验结果表明,新生态二氧化锰对实际微污染水具有很强的除有机物能力,如投加10mg·L-1的新生态二氧化锰,UV254的去除率最高达到40%以上,TOC的去除率最高也可以达到20%以上,但是混凝后水的浊度、溶解锰的含量都稍高于生活饮用水的标准。若将其作为助凝剂投加(1.37mg·L-1),强化硫酸铝的混凝作用,硫酸铝投量为10mg·L-1时,UV254的去除率可以提高20%以上,TOC的去除率可以提高10%左右,处理后水样的浊度、溶解锰和溶解铝含量都能够达到生活饮用水的标准。实际水加标实验表明,新生态二氧化锰混凝对松花江水中的苯酚、硝基苯和苯胺都有一定的去除,去除率能够达到20%以上,但是对苯甲酸的去除效果较差。实际水体中的钙离子对新生态二氧化锰混凝作用的影响弱于其在蒸馏水中。新生态二氧化锰对实际水中TOC的饱和吸附量明显大于其在蒸馏水中对小分子有机物的饱和吸附量。更多还原

【Abstract】 Organic contamination of the drinking source water is a serious problem in water supply. The organics may form more toxic byproducts in the disinfection process with chlorine if they can not be removed in the process of coagulation. But the regular coagulants and coagulation process can not satisfy the new standard of drinking water for orgnanic micropollutants. New type of coagulant which has the advantage of high efficiency, convenience and no side effect should be developed.Manganese dioxide formed in situ was prepared by manganese sulfate and potassium permanganate online added under neutral pH condition. The mictopography of manganese dioxide formed in situ was characterized by AFM, FT-IR and BET. Results showed that the particles of manganese dioxide formed in situ are un-regularly spherical form and have small particle size less than 100nm. With the higher specific surface area, the particles of the manganese dioxide formed in situ will coagulate instantly as they are formed in aqueous solution.The pH of the aqueous solution affects the type of the reaction of manganese dioxide formed in situ with organics, as seen from the results of phenol reacting with manganese dioxide formed in situ. The adsorptive reaction was happened for manganese dioxide formed in situ with phenol under neutral pH condition, while the oxidation-reduction reaction was observed under strongly acidic condition and the phenol removal efficiency was very high. The oxidative products of phenol were p-benzoquinone and coupled phenol.Four kinds of organic compounds with different functional groups on aromatic, that are aniline, phenol, nitrobenzene and benzonic acid were chosen for adsorption experiments. In these four organics, the adsorption capacity increased in the order aniline>phenol>nitrobenzene>benzoic acid. According to the analysis on organics structure and the surface characteristics of manganese dioxide formed in situ, conclusion may be obtained that the surface area of oxide and electrostatic are important for adsorption and the hydrophobicity is the minor effect. The adsorption of organics by manganese dioxide formed in situ was more conform to the Langmuir adsorption mode.Manganese dioxide formed in situ was selected as coagulant and coagulant aid to investigate the organic removal in micro-polluted water and the technical parameters were fixed. Results showed that UV254 and TOC were removed as high as 40% and 20% respectively. Organics were mainly removed in the process of fast mixing. While UV254 and TOC can be improved more than 20% as the manganese dioxide formed in situ enhanced the coagulation of aluminum sulfate.Tannic acid was selected as a reproducible surrogate for NOM because it is present in natural waters and it resembles humic substances in some properties such as adsorption, color, and complex formation. Tannic acid also contains both saccharide and aromatic acid components that are significant in surface waters. The adsorption results showed that the removal efficiency for tannic acid adsorbed by manganese dioxide formed in situ is higher than benzoic acid. Calcium can accelerate tannic acid removed by manganese dioxide formed in situ. This means that the adsorption of organic acid by manganese dioxide formed in situ is correlated with the value of its molecule weight. The dose of KMnO4 is not the essential factor for tannic acid removal, while the adsorption of newly formed MnO2 is the most important factor for tannic acid removal.UV254 and TOC removal percentage were 40% and 20% respectively as 10mg·L-1 manganese dioxide formed in situ was added to treat micro-polluted Songhua River. But the residual turbidity and soluble manganese of disposed water are higher than the standard of drinking water. As manganese dioxide formed in situ was added with a dose of 1.37mg·L-1 to enhance the coagulation by aluminum sulfate (10mg·L-1), UV254 and TOC can be increased more than 20% and 10% respectively. The turbidity, soluble manganese and soluble aluminum of treated water were all satisfied the standard of drinking water. Results of coagulation on the water of Songhua River with standard materials showed that manganese dioxide can remove nitrobenzene, phenol and aniline in the Songhua River and the organic removal efficiency is more than 20%. Benzonic acid can not adsorb by manganese dioxide formed in situ no matter in distilled water or in Songhua River. Ca2+ existed in Songhua River has less effect on the adsorption of manganese dioxide formed in situ than in distlled water. Manganese dioxide formed in situ has higher TOC adsorption capacity for natural water than distilled water.更多还原