论文总字数：19734字

摘 要

随着工业化社会加速发展，化石燃料的消耗量增长，排放了很多CO₂气体，引发了一连串的环境问题，从源头处捕集和封存CO₂是控制CO₂排放的最有效方法。石油是目前人类最主要的能源，高速的消耗让石油日益枯竭。储量丰富的天然气（主要成分为CH₄）是石油的良好替代品，天然气清洁燃烧的特性能减轻环境污染。解决天然气储存问题是实现天然气利用的关键。吸附法捕集CO₂和储存CH₄具有操作简单，能耗低，投资小等优点，高效稳定的吸附剂是实现吸附法利用的关键。

利用KOH活化酚醛树脂合成多孔碳材料，控制活化温度与KOH和前驱体的质量比制备不同孔隙结构的多孔碳材料，测量它们的CO₂、CH₄吸脱附等温线，研究其吸附量和孔隙结构之间的关系，寻找出较好的活化条件。

实验结果表明：活化温度为650 ^oC和KOH和前驱体质量比为2时为较好的活化条件，此时CO₂和CH₄吸附量分别为159.66 cm³ g^-1和79.28 cm³ g^-1。随着活化温度升高，多孔碳材料微孔孔隙结构先增加后减少，极微孔数量也先增加后减少。当活化剂用量增加后，活化剂刻蚀作用加剧，生成的孔隙结构越来越多，但同时也生成了越来越多的介孔，平均孔径越来越大，极微孔数量也先增加后减少。

总孔容和微孔孔容并不是影响CO₂和CH₄吸附性能的决定性因素，孔径较小的极微孔对CO₂和CH₄的吸附具有决定性作用。

关键词：化学活化法；多孔碳材料；KOH；CO₂吸附；CH₄吸附

Preparation of Porous Carbon Materials by Potassium Hydroxide Activation and Its Adsorption Properties

Abstract

With the acceleration of industrialization, the use of fossil fuels has increased dramatically, resulting in the emission of a large amount of CO₂ gas and a series of environmental problems. The capture and storage of CO₂ from the source is the most effective way to control CO₂ emissions. Petroleum is currently the most important energy source used by humannity, and high-speed consumption has made petroleum increasingly depleted. Rich reserves of natural gas (mainly composed of CH₄) are good substitutes for petroleum, and the clean combustion characteristics of natural gas can reduce environmental pollution. Solving the problem of natural gas storage is the key to realizing the utilization of natural gas. The method of adsorption to capture and storage CO₂ and CH₄ has the advantages of simple operation, low energy consumption, low investment, etc. The efficient and stable adsorbent is the key to realize the utilization of adsorption method.
KOH-activated phenolic resin was used to synthesize porous carbon materials, and porous carbon materials with different pore structures were made by controlling the temperature and the mass ratio of KOH and precursors. The adsorption and desorption isotherms of CO₂ and CH₄ were measured, and their adsorption capacity and pore structure were studied. The relationship between, find out the best activation conditions.
The experimental results show that the optimum activation conditions are activation temperature of 650 ^oC and the mass ratio of 2. The adsorption capacities of CO₂ and CH₄ are 159.66 cm³ g^-1 and 79.28 cm³ g^-1, respectively. With the increase of activation temperature, the pore structure of porous carbon materials increases first and then decreases, and the number of ultramicropores first increases and then decreases. When the amount of activator is increased, the etching effect of the activator is intensified and more and more pore structures are generated. However, more and more mesopores are generated, the average pore size is larger and larger, and the number of ultramicropores is increased first and then decreases.
The total pore volume and micropore volume are not the decisive factors affecting the adsorption performance of CO₂ and CH₄. The ultramicropores play a decisive role in the adsorption of CO₂ and CH₄.

Key Words: Chemical activation method; Porous carbon material; KOH; CO₂ adsorption; CH₄ adsorption

目 录

摘要 I

Abstract i

第一章 绪论 1

1.1 引言 1

1.2 CO₂的捕集技术 1

1.2.1 膜分离法 1

1.2.3 吸收法 2

1.2.4 吸附分离法 2

1.3天然气(甲烷)的储运技术 3

1.3.1液化天然气(LNG)技术 3

1.3.2压缩天然气(CNG)技术 3

1.3.3天然气水合物(NGH)技术 4

1.3.4吸附天然气(ANG)技术 4

1.4 多孔碳材料 5

1.5 多孔碳材料的制备方法 5

1.6 论文研究内容、目的和意义 6

第二章 实验部分 7

2.1 实验药品、气体和仪器 7

2.1.1 实验相关药品 7

2.1.2 实验仪器 7

2.1.3 实验气体 8

2.2 样品的表征 8

2.2.1 比表面积及孔结构测定 8

2.2.2 气体吸附性能测定 8

第三章 结果与讨论 10

3.1 实验内容 10

3.1.1 酚醛树脂的制备 10

3.1.2 多孔碳材料的制备 10

3.2 活化温度对多孔碳材料吸附性能的影响 10

3.2.1 N₂吸附表征 10

3.2.2 CO₂吸附等温线 12

3.2.3 CH₄吸附等温线 13

3.3 不同活化剂与前驱体质量比多孔碳材料吸附性能的影响 13

3.3.1 比表面积及孔径分析 14

3.3.2 CO₂吸附等温线 15

3.3.3 CH₄吸附等温线 16

第四章 结论与展望 17

4.1 结论 17

4.2 展望 17

参考文献 18

致谢 21

第一章 绪论

1.1 引言

过度使用化石能源致使大量的CO₂气体被排放，火力发电厂尾气中CO₂约占15%，N₂约占70%^[1-3]，这些CO₂气体是形成全球温室效应的主要原因^[4]。所以现在人们最关心的话题之一就是如何使CO₂的浓度降低。目前很多的环境问题大多数是由CO₂浓度太高导致的。这些问题不仅影响了人类生活，还威胁到了生态环境^[5]。

18世纪中期，CO₂被大量排放因为发电、石油加工等。2002年，全球化石燃料燃烧排放的CO₂量达到了250亿吨^[6]。天然气(85-95%为CH₄)作为煤油替换燃料在20世纪80年月就已引起了高度关注。天然气相比于其他汽车燃料占据非常多的上风:第一，天然气量大。据初步估算，全球天然气水合物资源量约为21×10¹⁵ m^3[7]，是化石燃料的两倍，足够让人们千年不愁能源。第二，天然气是较清洁的能源，对环境比较友好。目前由汽车燃油导致的空气污染日益严重，而天然气中含硫较少，且为易脱除的有机硫化物^[8]。天然气汽车比用燃油的汽车污染更少，因为其尾气中不包含的苯类毒素，而且氮氧化物和碳氧化物的排放量大大降低，颗粒物质也明显减少。第三，天然气汽车比使用汽油的汽车更易于保护也耐磨损。事实上，天然气作为汽车燃料，除了车载存储问题外，其它各方面都优于汽油、柴油以及诸如甲醇之类的代用燃料^[9]。

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