【作者】 张灿；

【导师】 孙洪良；

【作者基本信息】 浙江工商大学 ， 环境工程， 2010， 硕士

【摘要】 酚类化合物是水环境中主要的有机污染物,具有毒性大、难降解等特点,研究如何有效地控制和治理含酚废水具有十分重要的意义。有机膨润土对含酚废水的吸附研究已取得一定进展,但目前使用的有机改性剂主要为长、短碳链的烷基季铵盐表面活性剂,而对含苯环的季铵盐表面活性剂的改性研究鲜见报道。由于苯环之间π-π键的相互作用,能够增强对芳香类有机化合物的吸附,本文重点研究了使用含苯环的季铵盐阳离子表面活性剂改性的芳基有机膨润土对酚类化合物的吸附性能。实验选择短碳链的四甲基氯化铵(TMA)、苄基三甲基氯化铵(BTMA)、苄基三乙基氯化铵(BTEA)和长碳链的十六烷基三甲基溴化铵(CTMAB)、十六烷基二甲基苄基氯化铵(HDBAC)等5种结构不同的季铵盐阳离子表面活性剂分别对膨润土原土进行改性,系统研究了改性后有机膨润土的结构特征、对水中酚类化合物的吸附性能、机理以及影响因素,重点探讨了苯环结构对芳基有机膨润土吸附芳香类有机化合物性能的影响。研究结果表明：(1)长、短碳链的季铵盐阳离子通过离子交换作用进入到膨润土层间,改变了膨润土原土的层间距和层间域结构,其表面性质发生明显变化,吸附性能显著增强。(2)振荡时间、温度、用土量和pH等因素对有机膨润土吸附苯酚的性能有较大影响,且改性使用的季铵盐阳离子表面活性剂的结构不同(碳链长短、有无苯环),所得有机膨润土对苯酚的吸附量随单因素变化的规律也不相同。(3)比较芳基有机膨润土和烷基有机膨润土的吸附性能发现,在较低的有机物初始浓度(<400 mg／L)条件下,含苯环的BTMA和HDBAC 2种芳基有机膨润土对芳香化合物的吸附性能分别优于不含苯环的TMA和CTMAB烷基有机膨润土,而短碳链的40BTMA有机膨润土的吸附优势比长碳链的100HDBAC有机膨润土更明显。这主要是因为苯环之间的π-π键具有相互增强作用,能够促进含苯环结构的芳基有机膨润土吸附含有苯环结构的芳香化合物。(4)三参数的Redlich-Peterson模型能够克服传统的Langmuir模型、Freundlich模型和线性模型的缺陷和局限性,对不同结构的长、短碳链有机膨润土的等温吸附曲线都能很好地拟合,是一种比较理想的等温吸附模型。模型拟合结果表明,短碳链有机膨润土对酚类化合物的吸附以表面吸附为主,但膨润土表面孔隙分布不均匀,且对化合物的吸附并不是均匀的单层吸附；长碳链有机膨润土对酚类化合物的吸附以层间有机相的分配作用为主,但同时还存在膨润土的表面吸附作用,其等温吸附曲线也具有非线性特征。(5)膨润土的结构、吸附机理、有机物水溶性和辛醇-水分配系数(Kow)等因素都会影响有机膨润土对有机物的吸附性能,因此,长、短碳链芳基有机膨润土对各种酚类化合物吸附去除能力的大小顺序不同。短碳链的40BTMA适用于吸附辛醇-水分配系数较小、水溶性较大、亲水性较强的酚类化合物,而长碳链的100HDBAC更适合用于吸附处理辛醇-水分配系数较大、疏水性较强的酚类化合物。利用这个特点可以将芳基有机膨润土应用于新型、高效、环保的吸附材料的研发。更多还原

【Abstract】 Phenolic compounds are primary organic pollutants in waters, and they are greatly poisonous and hard to be degraded. So the study on how to effectively control and treat phenolic wastewater is extremely significant. It has been made some progresses in researches on adsorption of phenolic wastewater by organobentonites, but the organic modifiers currently used are mainly long and short carbon chain alkyl quaternary ammonium surfactants, while quaternary ammonium surfactants containing benzene rings are rarely applied. Because the mutual effects ofπ-πbonds between benzene rings can enhance the adsorption of aromatic compounds, in this experiment, the adsorption capability of phenolic compounds by organobentonites which were modified by aryl quaternary ammonium surfactants was specially studied.The original bentonite was modified respectively by five kinds of quaternary ammonium surfactants, such as TMA, BTMA, BTEA, CTMAB and HDBAC, which were in different structures. Structure characteristics of organobentonites, adsorption capability, adsorption mechanism and adsorption influencing factors of phenolic compounds by organobentonites were systematically studied. Meanwhile, the effects of benzene ring structure on adsorption capability of aromatic compounds by aryl organobentonites were specially discussed. The main results were as follows:(1)Both long and short carbon chain quaternary ammonium cations were able to insert into interlayer of original bentonite through ion exchanges, and change the layer spacing and structure, so surface properties of original bentonite were obviously changed and the adsorption capability was significantly enhanced.(2)Shaking time, temperature, sample dosage and pH all could greatly influence the adsorption of phenol by organobentonites. And if the structures of quaternary ammonium cations were different, for example, the lengths of organic cations carbon chain were different or the benzene ring structure existed or not, changing laws of adsorption capacity with the changing of single factors were also different.(3)Comparing the adsorption capability of aryl organobentonites with alkyl organobentonites, we could find that at a lower initial concentration (< 400 mg/L), BTMA and HDBAC aryl organobentonites with benzene rings respectively had higher adsorption capability than TMA and CTMAB alkyl organobentonites without benzene rings, and the adsorption superiority of 40BTMA-organobentonite was more obvious than 100HDBAC-organobentonite. This was mainly because theπ-πbonds between benzene rings had mutually reinforcing effects, which could accelerate the adsorption of aromatic compounds by aryl organobentonites.(4)Redlich-Peterson model with three parameters could overcome the limitations of traditional models, such as Langmuir model, Freundlich model and Linear model, and could fit adsorption isotherm curves of both long and short carbon chain organobentonites well. So Redlich-Peterson model was an ideal adsorption model. Results of model fitting showed that, the adsorption of phenolic compounds by short carbon chain organobentonites of different structures was mainly surface adsorption, but the pores of bentonite surface distributed unevenly and the adsorption of organic compounds was not the uniform monolayer adsorption; moreover, the adsorption of phenolic compounds by long carbon chain organobentonites of different structures was mainly based on the distribution of interlayer organic phases, but there was still surface adsorption, so the adsorption isotherm curves also showed non-linear characteristic.(5)The structure of bentonites, adsorption mechanism, water solubility and octanol-water partition coefficient (Kow) of organic compounds all had effects on adsorption of organic compounds by organobentonites. Therefore, the orders of adsorption capability of different phenolic compounds by long and short carbon chain aryl organicorganobentonites were different. In a word,40BTMA-organicorganobentonite of short carbon chain was suitable to adsorb the phenolic compounds which had smaller octanol-water partition coefficient, higher solubility and stronger hydrophilicity; while 100HDBAC-organicorganobentonite of long carbon chain was suitable to adsorb the phenolic compounds which had larger octanol-water partition coefficient and stronger hydrophobicity. According to this feature, we can apply aryl organobentonites to research and develop new, efficient and environmental adsorption materials.更多还原