硅藻土—分子筛复合材料的制备及其吸附性能研究

发布时间：2018-04-14 08:07

本文选题：硅藻土 + 分子筛　；参考：《吉林大学》2015年硕士论文

【摘要】：随着我国水资源短缺矛盾日益加剧，开发新型吸附剂对污水、废水进行处理和回用越发紧迫。硅藻土在我国储量十分丰富，并且具有轻质、孔容大、化学稳定性好、耐酸、耐磨、耐热等特点，成为一种具有潜在前景的环境吸附材料。分子筛具有孔径规则均匀、结构多样、极性可调控、选择吸附性强、稳定性好、容易再生等优势，适用于处理组成复杂、有毒、难降解的低浓度有机废水。但是硅藻土存在着孔径过大、吸附效率较低等不足；分子筛也存在着制备成本高昂，难以回收、存在团聚效应等缺点。将硅藻土与分子筛复合，制备功能性吸附材料应用于污染物处理具有重大的应用研究价值。本文主要研究结果如下：（1）研究了三种硅藻土和十三种分子筛对模拟苯酚废水的吸附性能。硅藻土对苯酚吸附性能较差，其中硅藻土3#最优，去除率为14%。分子筛对苯酚吸附能力随分子筛种类变化，MFI晶型的ZSM-5系列分子筛附性能较好，其中silicalite-1最优，去除率可达82%以上。选择硅藻土3#和silicalite-1分子筛作为后续复合材料制备的原材料。并且对硅藻土3#和silicalite-1分子筛进行XRD图谱和SEM表面形貌分析。（2）分别采用复配法、原位法、二次法以及微介孔法制备硅藻土-分子筛复合材料，研究了复合材料的XRD图谱和SEM形貌。结果表明，复配法、二次法和微介孔法复合材料的XRD图谱分别包含硅藻土3#和silicalite-1分子筛的特征峰，原位法复合材料XRD图谱中不存在无定形SiO2特征峰；复配法复合材料SEM显示，，硅藻土分子筛不均匀结合，原位法、二次法和微介孔法复合材料SEM显示，分子筛均在硅藻土3#表面进行生长，其中二次法生长优于原位法。（3）对所制备的复合材料进行吸附时间、吸附剂用量、吸附pH等一系列研究，得出在酸性条件下投加20g/L复合吸附材料，可对50mg/L苯酚有效吸附77%。与硅藻土3#的14%去除率相比，复合材料的吸附能力明显提升。
[Abstract]:With the increasing shortage of water resources in China, it is more and more urgent to develop new adsorbents to treat and reuse sewage and wastewater.Diatomite is rich in reserves in China, and has the characteristics of light weight, large pore volume, good chemical stability, acid resistance, wear resistance, heat resistance and so on. It has become a potential environmental adsorption material.Molecular sieve has the advantages of regular pore size, diverse structure, adjustable polarity, strong selective adsorption, good stability and easy regeneration. It is suitable for the treatment of low concentration organic wastewater with complex composition, toxic and difficult to degrade.However, diatomite has many disadvantages, such as too large pore size and low adsorption efficiency, and molecular sieve has some disadvantages such as high cost, difficult to recover and agglomeration effect.The preparation of functional adsorption materials by combining diatomite with molecular sieve has great application value in pollutant treatment.The main results of this paper are as follows:The adsorption properties of three kinds of diatomite and thirteen molecular sieves for simulated phenol wastewater were studied.The adsorption performance of diatomite to phenol was poor, among which diatomite was the best and the removal rate was 14%.The adsorption ability of molecular sieve for phenol varies with the type of molecular sieve. The ZSM-5 series molecular sieves with crystal form of MFI have better adsorbability, among which silicalite-1 is the best, and the removal rate is more than 82%.Diatomite and silicalite-1 molecular sieves were selected as raw materials for the subsequent composite materials.The XRD spectra and SEM surface morphology of diatomite and silicalite-1 molecular sieve were analyzed.(2) diatomite molecular sieve composites were prepared by combination method, in-situ method, secondary method and micromesoporous method, respectively. The XRD spectra and SEM morphology of the composites were studied.The results showed that the XRD spectra of composite materials by compounding method, quadratic method and micromesoporous method contained the characteristic peaks of diatomite and silicalite-1 molecular sieve, respectively, and there were no amorphous SiO2 characteristic peaks in XRD atlas of in-situ composite materials, and the SEM spectra of composite materials by compound method showed that,SEM showed that the molecular sieve grew on the surface of diatomite by in-situ method, secondary method and micromesoporous method, and the secondary method was superior to the in-situ method.(3) A series of studies were carried out on the adsorption time, adsorbent dosage and adsorption pH of the prepared composite materials. It was concluded that the 50mg/L phenol could be effectively adsorbed by adding 20g/L composite adsorption materials under acidic conditions.Compared with the 14% removal rate of diatomite, the adsorption capacity of the composite was obviously improved.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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