【作者】 杨超；

【导师】 陆安慧；

【作者基本信息】 大连理工大学 ， 工业催化， 2016， 硕士

【摘要】 近年来,全球CO2的排放量越来越大,由其带来的温室效应也愈加严重。CO2是一个矛盾的统一体,它既是一种最主要的温室气体,又是一种重要的化工Cl资源,因此将其富集分离并进一步转化利用得到了科学工作者们的广泛关注。在众多的CO2捕集方法中,吸附法由于具有腐蚀性小,能耗低,操作简单,脱除深度大等优点而被广泛研究,其研究核心是高效吸附剂的设计与制备。多孔炭材料具有优良的疏水性,发达的孔隙结构,而且其循环稳定性优良,制备成本低,再生能耗小,是一种具有实际应用价值的高效固体吸附剂。通过化学合成的方法制备的聚合物基多孔炭材料的孔隙结构可控,表面化学官能团可调,也可依据吸附场合的需要,对吸附剂进行复合改性。本论文紧紧围绕整体式多孔炭的设计与制备,对样品的大孔孔隙进行调控以增强其对CO2的体积吸附量,之后又探索了氧化物复合的整体式多孔炭在烟道气温度条件下(50-150℃)的吸附行为,具体内容如下：(1)为了增强炭质吸附剂的CO2体积吸附量,本章基于苯并噁嗪化学反应体系,以间苯二酚和甲醛为炭前驱体,不同尺寸的氧化石墨烯为片状结构导向剂,通过改变不同片层尺寸氧化石墨烯的配比,制备了一系列整体式多孔炭材料。该类吸附剂具有可调的大孔结构,同时保持比表面积、微孔结构和表面官能团基本相同。样品的SBET均约为500 m2 g-1,微孔孔容约为0.23 cm3 g-1,微孔的峰值孔径约为0.5 nm。在0.6-1.8μm范围内,大孔孔径与构成其炭片中的大尺寸炭片所占比例呈线性关系。研究结果表明在273K,800 mmHg条件下,样品的CO2静态吸附量为3.8 mmol g-1,由小尺寸炭片组装样品的体积吸附量是由大尺寸炭片组装样品的2.5倍。对于CO2/N2和CO2/CH4混合气的分离比分别为15.9和3.3,而且其再生性能、循环稳定性能均优良,在室温条件下,用氩气吹扫置换即可完全脱附再生。(2)针对炭材料在烟道气温度条件下CO2吸附量较低的问题,本章将锂藻土(Laponite)原位地复合到整体式炭前驱体聚合物中,通过改变锂藻土的掺入量,制备了-系列氧化物复合的整体式多孔炭材料。代表性样品的SBET高达797 m2 g-1,微孔比表面积为353 m2 g-1。研究结果表明在298 K,800 mmHg条件下其CO2静态吸附量为2.64mmol g-1,在343 K,800 mmHg条件下仍具有较高的吸附量(1.24 mmol g-1),由克劳修斯-克拉佩龙方程计算知其等量吸附热为42 kJ mol-1,表明样品与CO2之间的相互作用力较强,利于气体吸附分离。在常温常压条件下,其对CO2/CH4混合气的分离比为4.0。更多还原

【Abstract】 In recently years, the greenhouse effect is becoming more and more serious with the incresing CO2 emission worldwide. As known, carbon dioxide (CO2) is a two-sided gas. It is a main kind of greenhouse gas, on the other hand, it is also an important chemical resource, so CO2 capture and conversion had attracted wide attention from scientific researchers. Among all of the techniques for CO2 capture, adsorption method had been investigated deeply because of its no corrosion, low power consumption, easy operation, and depth removal, the core in this method is the design and synthesis of the adsorbents. Porous carbons are a kind of efficient adsorbents due to their hydrophobicity, developed porousity, recycling stability, low cost and low renewable energy consumption. Polymer-based porous carbons are synthesized chemically, their pore structure and surface functional group can be controlled precisely. In addition, the doping method can be used to meet the needs of adsorption under different conditions.In this study, a series of carbon nanosheets monoliths were designed and prepared. The macropore structures of the samples were tuned in order to enhance the volumetric capacity. In addition, oxides doped carbon monoliths were synthesized and their adsorptive properties at varied temperatures(50-150℃) were studied. The specific content is as follows:(1) To enhance the CO2 capacity on a volumetric basis of carbonaceous adsorbents, a series of porous carbon monoliths were prepared by using resorcinol and formaldehyde as the carbon precursors and graphene oxides with varied sizes as the sheet-directing agents. We can realize the variation of the macropore volumes but retaining the micropore structure, surface groups identical of the obtained monoliths. The SBET was about 500 m2 g-1, micropore volume was about 0.23 cm3 g-1, and the pore size concentrated at ca.0.5 nm. The results indicated that the macropore diameter varied from 0.6μm to 1.8μm, and fitted linear correlation with the graphene oxides mixing proportion. The adsorption capacities at 273 K and 800 mmHg for all of the adsorbents were about 3.8 mmol g-1, and the CO2 capacity on a volumetric basis of the sample consist of small size carbon nanosheets was ～2.5 times higher than the sample consist of large size carbon nanosheets. The separation ratios of CO2/N2 and CO2/CH4 gas mixture were 15.9 and 3.3, respectively. In addition, all of the monoliths had excellent recycling stability, and can be regenerated easily through argon blow at ambient temperature.(2) In order to improve the adsorption property of porous carbons at elevated temperature other than room temperature, Laponite was doped into the carbon framework. A series of samples were prepared through changing the dosage of Laponite. SBET of the typical sample was 797 m2 g-1, micropore area was 353 m2 g-1, the adsorption capacities at 298 K and 343 K,800 mmHg were 2.64 mmol g-1 and 1.24 mmol g-1 respectively, and the separation ratio of CO2/CH4 gas mixture was 4.0. The isosteric heat of adsorption of the sample was 42 kJ mol-1, which indicated the strong interaction between CO2 and the adsorbent.更多还原