改性膨润土的制备表征及其应用研究

发布时间：2019-02-23 13:26

【摘要】：膨润土(Bent)是一种以蒙脱石为主要成分的天然矿物材料,因其独特的化学组成和特殊的结构而具有较高的热稳定性和较大的比表面积,常用作各种环境友好型催化剂的载体。为了使载体具有更大的比表面积和更高的热稳定性,往往需要对天然膨润土进行纯化以去掉杂质得到高含量的蒙脱石,然后通过负载等手段制得不同类型的改性膨润土,然后将其用作催化剂,应用到催化、吸附等方向。这种以膨润土作为载体的催化剂,具有制备成本低、催化活性高、易分离和可多次循环使用的优点,是一种有广泛应用前景的绿色催化剂。本文以提纯纯化的膨润土为载体,制备出负载硫酸高铈、负载三氯化铝、羟基铁铝柱撑三种催化剂,并通过FTIR、XRD、SEM、TG、BET等手段对其结构与形貌加以表征,研究了三种催化剂分别对酯化反应,酰化反应,吸附作用的性能。主要内容如下:1.以河南信阳钠基膨润土为原料,经过提纯、纯化、酸化处理,制备成载体,采取浸渍蒸发法制备蒙脱石负载硫酸高铈固体酸催化剂。通过FTIR、XRD、SEM、TG、BET等手段对蒙脱石负载硫酸铈固体酸催化剂进行了表征。利用合成乙酸异丁酯的反应为催化性能的评价体系。结果表明:负载型催化剂具有良好的催化性能,在反应温度为100℃,醇酸比为1.12:1时,硫酸高铈负载量为20%,催化剂用量为1.5g,反应2 h时,催化效率最佳产率达到了88.9%。同时,反应后的催化剂容易分离。六次重复使用后的催化效率依然保持83.1%。2.采用浸渍蒸发法制备酸化蒙脱石负载AlCl3催化剂,通过FTIR、XRD、SEM、TG、BET等对催化剂进行结构表征分析,利用合成乙酸异戊酯的酰化反应,评定体系性能。结果显示,对乙酸异戊酯的催化性能研究表明,在反应温度为95℃,醇酐比为1.1:1时,催化剂用量为0.4g,反应40min时,催化效率最佳产率达到了85.38%。同时,反应后的催化剂容易分离。五次重复使用后的催化效率依然保持84.12%,说明这类负载型固体酸催化剂稳定性好。3.本章利用提纯和纯化后膨润土进行铁铝柱撑改性,通过FTIR、XRD、TG、BET等分析手段对铁铝柱撑膨润土进行表征,并以典型的有机染料酸性大红3R作为研究对象,探究铁铝柱撑膨润土对染料废水的吸附性能。结果表明:处理模拟废水酸性大红3R浓度为250mg/L,改性膨润土投加量为1.0g,反应温度为30℃,反应时间为40min时,反应的pH值为3,其色度去除率和COD的去除率分别达到91.26%、86.67%,浓度去除率达到98.8%。
[Abstract]:Bentonite (Bent) is a kind of natural mineral material with montmorillonite as its main component. Because of its unique chemical composition and special structure, bentonite has high thermal stability and large specific surface area. It is often used as the carrier of various environmentally friendly catalysts. In order to make the carrier have larger specific surface area and higher thermal stability, it is often necessary to purify the natural bentonite to get high content of montmorillonite, and then to prepare different types of modified bentonite by means of loading and so on. Then it is used as catalyst, applied to the direction of catalysis, adsorption and so on. This kind of catalyst with bentonite as the carrier has the advantages of low preparation cost, high catalytic activity, easy separation and can be reused for many times. It is a green catalyst with wide application prospect. In this paper, three kinds of catalysts supported on cerium sulfate, aluminum trichloride and hydroxy-ferric aluminum pillared were prepared by using purified bentonite as carrier, and their structure and morphology were characterized by FTIR,XRD,SEM,TG,BET. The properties of three catalysts for esterification, acylation and adsorption were studied. The main contents are as follows: 1. The solid acid catalyst of montmorillonite supported on cerium sulfate was prepared from Xinyang sodium bentonite from Henan Province by purification acidification and preparation of solid acid catalyst by impregnation evaporation. Montmorillonite supported cerium sulfate solid acid catalyst was characterized by FTIR,XRD,SEM,TG,BET. The synthesis of isobutyl acetate was used as a catalytic evaluation system. The results show that the supported catalyst has good catalytic performance. When the reaction temperature is 100 鈩，

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