ZSM-5X分子筛吸附分离木质素基芳香醛的研究

摘要：木质素是自然界中含量仅次于纤维素的天然高分子生物质，可以说这是一种取之不尽用之不竭的天然资源。将木质纤维素类物质通过有效分解途径转变为生物能源或生物质基化学品是解决能源危机及实现化学品原料绿色化的有效途径。采用催化氧化降解法制备高附加值的芳香醛化合物，虽具有降解产物种类相对较少且产率较高的优点，但也存在着三种主要芳香醛化合物难于分离的缺点。分子筛因其较好的催化、吸附等性能，广泛地应用于化工生产的各种领域。本论文选用具有高比表面积的ZSM-5X型分子筛作吸附剂，用不同初始浓度的芳香醛溶液与分子筛进行反应以及在溶液浓度相同的情况下让其在不同的温度条件下进行反应作为吸附条件，以获得最佳的吸附效果。实验结果表明：溶液的初始浓度越高，吸附效果越好，且30℃为最佳的吸附温度。在最佳吸附条件下，ZSM-5X分子筛对对羟基苯甲醛、香草醛及丁香醛的吸附量分别为0.03431g/g、0.02716g/g及0.0257g/g。67110

毕业论文关键词：木质素，芳香醛化合物，分子筛，吸附分离

Abstract: The content of lignin ranks only second to cellulose in biomass and it is a kind of inexhaustible natural resources. With the depleting of fossil resources together with the increasing concern about global warming and environmental pollution, biomass is considered as ideal and promising alternatives for the production of fuels and chemicals. The oxidative degradation products of lignin are extremely complex. Separation and purification of p-hydroxybenzaldehyde, vanillaldehyde and syringaldehyde from degradation products are technological difficulties in higher-added value application of lignin. Zeolites are crystalline, microporous materials with large surface areas and molecular size pore structure. ZSM-5X is one of the most frequently studied, investigated in numerous catalytic, adsorption and diffusion studies. In this study, the adsorption of p-hydroxybenzaldehyde, vanillaldehyde and syringaldehyde was investigated by ZSM-5X in order to find the optimized conditions of the process. The experimental results showed that the higher of the initial concentrations of the aromatic aldehydes, the greater of the adsorption capacities. The kinetic experimental results demonstrated that the zeolite showed different adsorption capacities for p-hydroxybenzaldehyde, vanillaldehyde and syringaldehyde with the adsorption capacities of 0.03431 g/g, 0.02716 g/g and 0.0257 g/g at the optimized temperature of 30 ℃, respectively.

Keywords: lignin, aromatic aldehyde compounds, molecular sieves, adsorption separation

1 绪论 4

1.1 生物质资源利用的意义 4

1.2 木质素的综合利用 4

1.3 分子筛的吸附分离应用 5

2 分子筛ZSX-5X对木质素基芳香醛的吸附动力学分析 5

2.1 实验材料 5

2.2 实验方法与步骤 6

2.2.1 对羟基苯甲醛、香草醛、丁香醛标准曲线的绘制 6

2.2.2 HPLC检测条件 8

2.2.3 最大吸附量计算 8

2.2.4 动力学实验步骤 8

2.3 结果与讨论 9

2.3.1 分析动力学 9

结论 24

参考文献 25

致谢 ZSM-5X分子筛吸附分离木质素基芳香醛的研究:http://www.751com.cn/huaxue/lunwen_75198.html