微介孔硅藻土—分子筛复合吸附材料的制备及其性能与应用研究

发布时间：2018-02-14 03:40

  本文关键词： 硅藻土 分子筛 微介孔复合吸附材料　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：在环境问题日益突出的今天,环境保护成为当今社会的主题。我国的缺水问题严重,废水回用成为人们的共识。分子筛晶体结构规范有序、孔道分布丰富均匀、表面性质可根据研究与应用需要设计调节,且其对多种物质有良好吸附作用,在水处理领域,有着巨大潜在的应用价值。硅藻土作为一种多孔材料表面结构独特,吸附性能良好,具备孔容量大、物理化学稳定性好等优势,资源丰富,价格便宜,已经作为吸附剂应用于各种工业废水处理过程中。但是硅藻土存在孔径过大、吸附效率不高等缺点;分子筛易团聚、成本高、难回收。因此,将分子筛与硅藻土复合,制备微介孔功能性吸附材料应用于水处理领域,具有重大研究与应用价值。本论文主要研究结果如下:(1)分别采用前处理法(在改性前驱体液中添加致孔剂CTAB(十六烷基三甲基溴化铵))与后处理法(用NaOH溶液碱浴刻蚀)在硅藻土-分子筛复合吸附材料中引入微介孔,研究并对比了所得微介孔复合吸附材料的吸附性能。结果表明,前处理法制备的微介孔硅藻土-分子筛复合吸附材料(配置前驱体液时n(CTAB(十六烷基三甲基溴化铵)):n(TEOS(正硅酸乙酯))=0.20)大孔-介孔-微孔数量比例合理、分布均匀,为最优化方法。丰富的多层次多级孔道充分物理吸附模型有机污染物分子,对酚类模型有机污染物(苯酚)有非常好的吸附效果。(2)使用最优化方法制备的微介孔硅藻土-分子筛复合吸附材料进行酚类模型有机污染物吸附实验,并对吸附条件与吸附效果进行一系列分析。结果表明,pH为在6-7(对于实际应用最为合理)时,溶液中酚类模型有机污染物主要呈分子形态,有利于具有丰富多级孔道结构的优选微介孔硅藻土-分子筛复合吸附材料对其进行吸附,且吸附效果非常显著,对酚类模型有机污染物(苯酚、邻苯二酚、间苯二酚、对苯二酚)的去除率均在90%以上。(3)研究将微介孔硅藻土-分子筛复合吸附材料与电化学方法组合在一起构成空气吹脱法-电化学氧化法-优选微介孔硅藻土-分子筛复合吸附材料吸附法组合工艺,应用于废水处理中。结果表明,在空气流速为140ml/min,吹脱温度为55℃,电流密度为30mA/cm2,吸附材料为优选硅藻土-分子筛复合吸附材料吸附时,此组合工艺对酚类模型有机污染物有最好的去除效果,在98%以上,要优于单纯使用优选微介孔硅藻土-分子筛复合吸附材料进行吸附的吸附效果。
[Abstract]:Nowadays, environmental protection has become the main theme of our society. The water shortage is serious in our country, and the reuse of wastewater has become a common understanding. The crystal structure of molecular sieve is orderly and the pore distribution is rich and uniform. The surface properties can be designed and adjusted according to the needs of research and application, and it has good adsorption to many substances, which has great potential application value in the field of water treatment. As a porous material, diatomite has a unique surface structure. It has many advantages such as good adsorption property, large pore capacity, good physical and chemical stability, abundant resources and low price. It has been used as adsorbent in various industrial wastewater treatment processes, but diatomite has too large pore size. The adsorption efficiency is not high, the molecular sieve is easy to agglomerate, the cost is high, the recovery is difficult. Therefore, the molecular sieve and diatomite are combined to prepare the micromesoporous functional adsorption material in the field of water treatment. The main results of this thesis are as follows: (1) the pretreatment method (adding the pore-causing agent CTAB (cetyltrimethylammonium bromide) in the modified precursor solution) and the post-treatment method (using NaOH solution in alkali bath) are adopted. Etching) introduction of micromesoporous pores into diatomite-molecular sieve composite adsorption materials, The adsorption properties of the micromesoporous composite adsorption materials were studied and compared. The micromesoporous diatomite-molecular sieve composite adsorbents prepared by the pretreatment method (when the precursor body fluid is configured, the ratio of macropore to mesoporous micropore is reasonable, the distribution is even, the proportion of macroporous, mesoporous and microporous is reasonable, the proportion of macroporous, mesoporous and microporous is reasonable, the distribution is even, the proportion of macroporous, mesoporous and microporous is reasonable, Rich multilevel and multilevel pore full physical adsorption model for organic pollutant molecules, The adsorption of phenolic model organic pollutants (Phenol) was studied by using the micromesoporous diatomite-molecular sieve composite adsorbed materials prepared by optimization method. A series of analysis was made on adsorption conditions and adsorption effects. The results showed that when pH was 6-7 (the most reasonable for practical application), the phenolic model organic pollutants in the solution were mainly in molecular form. It is favorable for the adsorption of micromesoporous diatomite and molecular sieve composite materials with rich multilevel pore structure, and the adsorption effect is very remarkable, for phenolic model organic pollutants (phenol, catechol, resorcinol, resorcinol, resorcinol, catechol, resorcinol). The removal efficiency of hydroquinone is above 90%. 3) study on the combination of micromesoporous diatomite and molecular sieve composite adsorption materials with electrochemical methods to form air blowing desorption-electrochemical oxidation method-selective micromesoporous diatomite-fractionation. Composite adsorption material adsorption process for sub-sieve, The results show that when the air flow rate is 140 ml / min, the blowing temperature is 55 鈩，

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