多孔材料表面改性及其吸附CO和香味物质缓释性能

发布时间：2018-07-02 13:44

本文选题：吸附 + 脱附　；参考：《华南理工大学》2015年博士论文

【摘要】：降焦减害是我国卷烟工业未来技术发展的重点工作。本文以研究降低烟气CO浓度和运用多孔材料实现致香成分缓释增香为潜在的应用背景,研究新型固体多孔材料及其吸附CO性能和香料化合物的吸附和缓释性能,主要涉及研制及改性活性炭、分子筛和MOFs等三类材料及研究其对CO的吸附性能;研究改性活性炭和无机多孔材料及其对不同官能团香料化合物的吸附和缓释性能。本课题属于化学工程、材料工程和表面科学交叉的研究领域,具有重要的科学研究价值和实际意义。本文系统地研究了活性炭、分子筛和MOFs等三类材料对CO的动态吸附性能。采用固定床吸附技术测定了CO在不同种类吸附材料上的吸附透过曲线,分析了吸附材料孔隙结构和表面性质对CO吸附性能的影响。结果表明:在模拟烟气CO浓度的动态条件下,传统活性炭分子筛材料对CO的吸附容量较低,均低于3 mL/g;而三种MOFs材料对CO吸附性能明显优于传统吸附材料,特别是MOF-74(Ni)对CO的动态吸附容量可达45.6 mL/g,远远高于其他材料。这是由于MOF-74(Ni)具有较高的不饱和金属活性位密度,其骨架上的Ni能与CO分子形成π键络合,能极大提高其对CO的吸附能力。本文应用Cu(I)盐和Ag(I)盐对β分子筛进行改性,并研究了它们对CO的吸附性能。结果表明:负载量为0.1 g/g的Ag(I)@β分子筛对CO的最大的工作吸附量可达9.5mL/g;负载量为0.4 g/g的Cu(I)@β分子筛对CO的最大工作吸附容量可达27.1 mL/g,是相同条件下原始β分子筛吸附容量的14倍。同时,本文也采用了IAST模型对材料CO选择性吸附性能进行模拟,计算结果显示:0.4Cu(I)@β分子筛对CO/CO2和CO/N2均具有良好的吸附选择性;在10 KPa以内,该材料对CO/N2和CO/CO2的吸附选择性分别高达到1600-5200和120-270;在20-100 KPa条件下,对CO/N2和CO/CO2的吸附选择性仍能达到500-1200和8-31。本文采用分子自发单层分散技术制备了CuCl@AC吸附剂,并进行了表征和CO吸附性能测定。结果表明:1.2CuCl@AC对CO的动态吸附量能达到14.4 m L/g,约是原始活性炭6.7倍;CO在1.2CuCl@AC和原始活性炭上的等量吸附热分别为43.4-56.7kJ/mol和约22.0 kJ/mol左右,说明活性炭改性后对CO的吸附结合力大大增强;1.2CuCl@AC对CO/CO2/N2混合体系均具有良好的选择吸附性;应用试验结果表明:将两种CuCl@ACs样品运用于实际卷烟产品中,能大幅度地降低卷烟主流烟气中的CO、HCN、NNK、NH3、B[a]P、苯酚、巴豆醛等七种关键有害成分,其中烟气中HCN含量的降幅分别高达79.72%和85.64%,能使卷烟危害性指数H值降低了57.42%-61.72%,具有广泛的应用前景。本文提出应用程序升温脱附(TPD)技术研究不同官能团香料化合物与多孔材料表面之间的相互作用力,分别测定了γ-壬内酯、大马酮、乙基香兰素、乙基麦芽酚、和乙酸乙酯以及β-苯乙醇等香料化合物在多种吸附材料上的TPD曲线并估算脱附活化能,讨论了香料化合物性质与多孔材料之间吸附力强弱的关系。研究表明:五种香料化合物在活性炭上的脱附活化能随着分子动力学直径的增大而增大,表明来自孔壁吸附势力场对香料化合物吸附结合力起主导作用;五种香料化合物在MCM-41上的脱附活化能大小顺序为:大马酮乙基香兰素乙基麦芽酚乙酸乙酯γ-壬内酯;β苯乙醇在五种材料上的脱附活化能的大小顺序依次为:XF活性炭MCM-41A型硅胶SBA-15B型硅胶,β苯乙醇在其中的四种非碳多孔材料上的脱附活化能是随着它们表面的酸性基团浓度增加而增大。由于活性炭表面存在共扼大?键可与β-苯乙醇的苯环发生?-?强吸附作用,因此β-苯乙醇在XF活性炭上的脱附活化能最大。本文提出一种采用碳化改性活性炭的方法,在不同的温度下对YK和SY1活性炭进碳化改性,研究了改性条件对材料的孔隙结构和表面化学的影响以及对香料物质吸附和脱附的影响。结果表明:碳化改性可有效改变活性炭表面酸性基团含量以及组成,它既能够不影响活性炭对两种香料化合物的吸附储存量,又能削弱活性炭表面对两种香料化合物的吸附结合力。例如,两种香料化合物在YK-300上的脱附活化能,分别比改性前下降了38.16%和30.75%,这对于指导香料缓释材料的研制和应用具有重要意义。
[Abstract]:In order to study the potential application background of reducing the concentration of CO and using porous materials to realize the sustained release of incense by using porous materials, this paper studies the absorption and release properties of new solid porous materials and their adsorbed CO properties and perfumery compounds, mainly involving the development and modification. Three kinds of materials, such as activated carbon, molecular sieve and MOFs, and their adsorption properties to CO, and the adsorption and release properties of modified activated carbon and inorganic porous materials and their functional group perfume compounds. This subject belongs to the research field of chemical engineering, material engineering and surface science, which has important scientific research value and practice. The dynamic adsorption properties of three kinds of materials, such as activated carbon, molecular sieve and MOFs, were systematically studied in this paper. The adsorption transmission curves of CO on different kinds of adsorbents were measured by fixed bed adsorption technology. The effects of pore structure and surface properties of the adsorbents on the adsorption energy of CO were analyzed. The results showed that the CO concentration of CO in the flue gas was simulated. Under the dynamic conditions, the adsorption capacity of the traditional activated carbon molecular sieve material to CO is lower than 3 mL/g, and the adsorption properties of the three MOFs materials are obviously superior to the traditional adsorbents, especially the dynamic adsorption capacity of MOF-74 (Ni) to CO is up to 45.6 mL/g, which is much higher than that of the other materials. This is due to the high unsaturated gold of MOF-74 (Ni). At the active site density, the Ni on the skeleton can form a pion bond with the CO molecule, which can greatly improve its adsorption capacity to CO. In this paper, Cu (I) salt and Ag (I) salt were used to modify the beta molecular sieve, and their adsorption properties to CO were studied. The results showed that the maximum working adsorption capacity of Ag (I) @ beta molecular sieve with a load of 0.1 g/g can reach the maximum capacity of the CO. /g; the maximum working adsorption capacity of Cu (I) @ beta molecular sieve with a load of 0.4 g/g to CO is up to 27.1 mL/g, which is 14 times the adsorption capacity of the original beta molecular sieve under the same condition. At the same time, the IAST model is used to simulate the selective adsorption performance of the material CO. The results show that 0.4Cu (I) @ beta molecular sieve is good for CO/CO2 and CO/N2. Under 10 KPa, the adsorption selectivity of the material to CO/N2 and CO/CO2 is up to 1600-5200 and 120-270, respectively, and the adsorption selectivity for CO/N2 and CO/CO2 can still reach 500-1200 and 8-31. under 20-100 KPa conditions and CuCl@AC adsorbents are prepared by molecular spontaneous monolayer dispersion technique, and the characterization and CO adsorption are carried out. The results show that the dynamic adsorption capacity of 1.2CuCl@AC to CO can reach 14.4 m L/g, about 6.7 times the original activated carbon, and the equal adsorption heat of CO on 1.2CuCl@AC and original activated carbon is 43.4-56.7kJ/mol and about 22 kJ/mol respectively, indicating that the adsorption binding force of activated carbon on CO is greatly enhanced; 1.2CuCl@AC to CO/CO2/N2 mixing. The experimental results show that the application of the two CuCl@ACs samples to the actual cigarette products can greatly reduce the seven key harmful components, such as CO, HCN, NNK, NH3, B[a]P, phenol, and croton aldehyde in the mainstream cigarette smoke, of which the decrease of HCN content in the smoke is up to 79.72% and 85.64% respectively. The H value of the smoke hazard index has been reduced by 57.42%-61.72% and has a wide application prospect. In this paper, the application of temperature programmed desorption (TPD) technology to study the interaction between different functional groups of aromatic compounds and the surface of porous materials was studied, and the determination of gamma nonylolide, damazone, ethyl vanillin, ethyl maltol, ethyl acetate and beta benzene respectively. The relationship between the properties of the aromatic compounds and the strong and weak adsorbability between the porous materials and the TPD curves on various adsorbents is discussed. The study shows that the activation energy of the five compounds on the activated carbon increases with the increase of the molecular dynamic diameter, indicating the adsorption of the pore wall. The power field plays a leading role in the adsorption and binding of aromatic compounds; the order of activation energy of the five kinds of spice compounds on MCM-41 is: the order of the desorption activation energy of the ethyl vanillin ethyl maltol acetate gamma nonylate, and the sequence of the activation energy of the desorption activation energy of the beta benzol on the five materials in sequence is the XF activated carbon MCM-41A type silica gel SBA-15B type The desorption activation energy of silica gel and beta benzol on four kinds of non carbon porous materials increases with the increase of the acid group concentration on their surface. The activation energy of the desorption activation energy of beta benzol on XF activated carbon is the greatest. A carbonated modified activated carbon was used to modify the carbonization of YK and SY1 activated carbon at different temperatures. The effects of the modification conditions on the pore structure and surface chemistry of the materials and the effect on the adsorption and desorption of the material were studied. The results showed that the carbonation modification could effectively change the content of the acid group on the surface of the activated carbon and the group. As a result, it can not affect the adsorption storage of activated carbon to two kinds of perfume compounds, but also weaken the adsorption binding force of the activated carbon surface to two kinds of perfume compounds. For example, the activation energy of the two spice compounds on YK-300 decreased by 38.16% and 30.75% before the modification, which should be developed for the development of spice sustained-release materials. It is of great significance to use.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ424

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