【作者】 周凌云；

【导师】 樊静；

【作者基本信息】 河南师范大学 ， 环境科学， 2014， 博士

【摘要】 CO2是导致温室效应的最主要成分，因此碳捕集技术的研究受到学术界和产业界的高度重视。以液体为主体的吸收技术和以固体为主体的吸附技术是碳捕集技术的主要组成部分。这其中，离子液体具有不挥发、不燃烧、热稳定性好、溶解能力强、结构和性质可调节并可循环使用等特性，在CO2的吸收/分离领域中展现了广阔的应用前景。除此之外，硅基介孔材料改性成的固态胺吸附剂由于具有高吸收性能和高选择性的特点，在捕集CO2领域也被广为关注。在本工作中，系统研究了功能化离子液体通过物理作用或化学作用对CO2的捕集行为，并通过扩大孔径缩短孔道进程，深入研究了载体形貌结构对硅基介孔材料胺化以后吸收CO2性能的影响，开发了具有高的CO2捕集能力、高选择性、高吸脱附动力学的碳捕集新材料。具体内容如下：1.合成了两种氟化咪唑离子液体1-丁基-3-甲基咪唑七氟丁酸[C4mim][CF3CF2CF2COO]和1-丁基-3-甲基咪唑九氟丁基磺酸离子液体[C4mim][CF3CF2CF2CF2SO3]，并进行了1H和13C NMR谱表征。在293.15至343.15K温度范围和高达8.9MPa的压力范围内测定了CO2、H2、N2和O2在这两种离子液体中的溶解度。利用这些数据，分别推导了这些气体在两种离子液体中的亨利常数标准吉布斯自由能，标准溶解焓，及标准熵，计算了对CO2/O2、CO2/N2和CO2/H2的溶解度选择性，分析了分子间的相互作用机理。将CO2在这两种离子液体中的溶解度与带有相同阳离子的其他含氟离子液体进行了比较。结果表明，CO2在这些离子液体中的溶解度大小顺序为：[C4mim][CF3CF2CF2CF2SO3]=[C4mim][Tf2N]>[C4mim][CF3CF2CF2COO]>[C4mim][CF3COO]>[C4mim][CF3SO3]>[C4mim][BF4]。此外，这些溶解度数据可以用Pitzer模型和Krichevsky-Kasarnovsky方程很好的关联。2.将三种氨基酸功能离子液体分散固载到介孔氧化硅材料SBA-15上用来吸收CO2。SBA-15的大比表面积和独特的孔道结构，大大提高了氨基酸离子液体对CO2的吸收能力。被充分分散的离子液体不再是堆积在一起而是被分别隔离至SBA-15独立的各个孔道表面，使得胺基基团与CO2按照1:1的摩尔当量比反应生成氨基甲酸，从而达到了0.91molCO2mol-1IL的吸收量。除此之外，CO2吸收能力可以通过调节氨基酸离子液体的负载量和吸收温度而得到优化。而且，吸收的CO2可以通过真空加热的解吸方式得到完全释放。分散到SBA-15上的氨基酸离子液体在五次吸收-解吸的循环过程中性能稳定。这项研究提供了一种与固体纳米多孔材料联用使得氨基功能化离子液体等摩尔吸收CO2的新方法，再加上它的稳定性和可再生性，使得它有可能大大促进离子液体碳捕集技术在工业上的实际应用。3.为了增强对CO2的吸附能力，制备了具有大孔径和短孔道行程的层状SBA-15，并用具有不同个数胺基基团的氨基硅烷试剂（mono-，di-和tri-氨基硅烷）与其进行硅烷化反应接枝胺基。深入分析了吸附剂载体的结构对胺负载量、CO2吸附能力和CO2/N2选择性的影响。结果表明，相比于传统的SBA-15，胺负载量和CO2吸附能力可分别增加66％和120％，对CO2/N2的选择性从37显著提高到169。这种新型吸附剂对CO2吸附焓达到67KJ mol-1，表明化学吸附起主要作用。此外，这种吸附剂可完全再生，并表现出良好的稳定性。这项研究提供了一种可以高效、可逆进行碳捕集的新材料。更多还原

【Abstract】 Since CO2is one of the most important greenhouse gases, the research and development in thecarbon capture technology have long been the focus of many academic and industrial studies. Solventabsorption and solid sorbent adsorption technology have been implemented and modified for the carboncapture. Ionic liquids have a number of unique properties, such as no-volatility, non-flammation,recyclability, high thermal stability, strong solubility capacity, and the tunability of molecularstructures andphysicochemical properties, and therefore have broad prospect in the absorption and separation of CO2. Inaddition, silicon modified mesoporous materials have also been widely concerned in the field of CO2capture due to its high absorption performance and high selectivity. The morphology of silicon-basedmesoporous materials were redesigned to adjust pore structure, morphology and structure in order to studythe impact on the adsorption properties and optimize CO2diffusion in the pore. In this work, functionalionic liquids were applied to capture CO2by physical or chemical action. In addition, by expanding thepore size and shorten the mosochannels, we developed the new mesoporous materials with high CO2capture capacity, high selectivity, high adsorption-desorption dynamics. Details are as follows:1. Ionic liquids1-n-butyl-3-methylimidazolium heptafluorobutyrate [C4mim][CF3CF2CF2COO]and1-n-butyl-3-methylimidazolium nonafluorobutyl sulfonate [C4mim][CF3CF2CF2CF2SO3] have beensynthesized and characterized by1H and13C NMR spectra. Solubilities of CO2, H2, N2and O2in these ILshave been determined at the temperature range from (293.15to343.15) K and the pressure up to8.9MPa.From these data, the Henry’s constant, the standard state solution Gibbs energy, standard state solutionenthalpy and standard state solution entropy of these gases in [C4mim][CF3CF2CF2COO] and[C4mim][CF3CF2CF2CF2SO3] were derived and analyzed from molecular interactions. And the solubilityselectivites for CO2relative to O2, N2and H2in both of ILs were calculated. The CO2solubility in these ILwas compared to other ILs sharing the same cation. This comparison shows that the solubility of CO2inthese ILs follows the sequence:[C4mim][CF3CF2CF2CF2SO3]=[C4mim][Tf2N]>[C4mim][CF3CF2CF2COO]>[C4mim][CF3COO]>[C4mim][CF3SO3]>[C4mim][BF4]. It is indicated thatthis kind of ILs would be a promising absorbents for CO2viewing from the absorption capacity andselectivity performance. Furthermore, these solubility data were well correlated by Pitzer model and Krichevsky-Kasarnovsky equation.2. The adsorption capacities of AAILs have been greatly enhanced by dispersed on themesoporous silica material SBA-15with special pore structures and large specific surface area. The CO2capture capacity reached up to0.91mol CO2per mol IL by forming carbamic acid in a ratio of one CO2perone amine (1:1stoichiometry) since SBA-15can disperse AAILs molecules from the bulk of the liquidphase to the surface of the support and separate them fully. In addition, CO2capture capacity can be finelytuned via AAIL loading and sorption temperature. Furthermore, the captured CO2can be released byheating under vacuum, and the adsorbent is quite stable after five adsorption-desorption cycles. The presentstudy provides a new approach for equimolar CO2capture of amine-functional ILs by the combination of asolid nanoporous material, which may provide an industrially attractive alternative for CO2capture of ILs.3. To enhance CO2adsorption capacity, a kind of platelet SBA-15with short channels and largepore diameter has been prepared and then grafted with various aminosilanes (mono-, di-, andtri-aminosilanes). Thorough analysis of the support structure and sorbent performance was estimatedthrough a combination of amine loading and CO2adsorption capacity and CO2/N2selectivity. It was shownthat compared to traditional SBA-15, the increase in amine loading CO2adsorption capacity can be up to66%and120%, respectively, for these novel sorbents, and the selectivity of CO2/N2was remarkablyenhanced from37to169. The CO2adsorption enthalpy reached67kJ mol1which suggests thatchemisorption was the predominant process. Moreover, these sorbents are regenerable and exhibit goodstabilities. Thus, this approach offers an alternative for the development of technological innovationtowards efficient and reversible processes for carbon capture.更多还原