【作者】 朱倩；

【导师】 张岐；

【作者基本信息】 江苏大学 ， 化学工程， 2021， 硕士

【摘要】 随着社会的进步以及人民生活水平的不断提高,在工业生产和日常生活中,人类对化石燃料的需求日益增长。然而,化石燃料的燃烧会产生大量的含硫烟气,若含硫烟气不经过处理直接排放会对环境造成污染,甚至对人们的身体造成巨大的伤害。因此,实现烟气的深度脱硫对于保护人与自然有着十分重要的意义。传统的烟气脱硫方法主要包括石灰石法、石膏法和液氨吸收法等。但这些传统的脱硫方法存在一些明显的缺点,例如吸收剂挥发性强、循环性能差以及易产生二次污染等,这极大地限制了它们在工业生产中的应用。因此,为了积极响应国家大力发展“绿色化工”的号召,本文设计并制备了一系列“绿色”无污染、可再生的三元低共熔溶剂（DESs）,并将其用于二氧化硫（SO₂）的深度吸收脱除。首先,通过调变胺类物质组合以及多元醇的碳链长度,制备了一系列双胺类三元DESs用于吸收酸性SO₂气体。实验结果表明,随着多元醇碳链长度的增加,吸收性能随之下降。研究得出,在298.15 K,1.0 bar的条件下,当二乙烯三胺（DETA）:乙酰胺（AA）:乙二醇（EG）的摩尔比为1:1:2时,其对SO₂的吸收容量可达0.82 g SO₂/g DESs（g/g）。考察了双胺类三元DESs的循环再生性能,结果表明双胺类三元DESs在保持最高吸收容量（0.82 g/g）的基础上至少可以再生使用6次。根据傅立叶变换红外光谱（FT-IR）和核磁共振氢谱（¹H-NMR）表征结果提出了双胺类三元DESs与SO₂的主要作用方式为酸碱中和作用,EG和AA与SO₂形成的氢键为辅助吸收方式。选择碱性小、毒性低的氯化胆碱（ChCl）代替AA合成了一系列胆碱类三元DESs。探究了胆碱类三元DESs的密度、粘度、热失重等物理性质与温度之间的关系,并通过热力学计算分析循环实验所需温度范围。在298.15 K,1.0 bar的条件下,当DETA:ChCl:EG的摩尔比为1:1:2时,其对SO₂的吸收容量可达0.87g/g,且胆碱类三元DESs在50 s左右即可达到一次吸收平衡。吸收结束后,胆碱类三元DESs可以实现再生,并在循环使用5次后仍保持较高的吸收容量。FT-IR和¹H-NMR表征证明了胆碱类三元DESs中亲核的Cl^-与SO₂之间形成的强电荷相互作用促进了吸收。选择毒性更低的咪唑类物质合成了一系列不同烷基链长度的咪唑类三元DESs。考察了不同烷基链长度的咪唑类三元DESs对吸收SO₂性能的影响,实验发现烷基链长度越短,吸收性能越好,当DETA:EG:氯化1-乙基-3-甲基咪唑（[Emim]Cl）摩尔比为2:1:2时,吸收容量高达1.02 g/g。该DESs在343.15 K的条件下可以实现再生,且再生性能优异。FT-IR、¹H-NMR、核磁共振碳谱(¹³C-NMR)表征和密度泛函理论（DFT）计算表明咪唑类三元DESs吸收容量高的主要原因是其具有多个吸收位点。更多还原

【Abstract】 With the development of society and the continuous improvement of people’s living standards,human demand for fossil fuels in industrial production and daily life has been gradually increasing as well.However,the burning of fossil fuels would produce a large amount of sulfur-containing gas,and the direct emission of sulfur-containing flue gas without any treatment would pollute the environment and would even cause great harm to people’s health.Therefore,achieving deep desulfurization of harmful gases is in a great of significance,as it would help for the protection of human being and nature.Traditional desulfurization methods for flue gas mainly include limestone method,gypsum method and ammonia–water absorption method.However,these traditional desulfurization methods have some obvious shortcomings such as strong volatility of the absorbent,poor cycle performance,and secondary pollution.These problems greatly limit their application in industrial production.Thus,in order to actively respond to the country’s policy of"green chemical industry",green,pollution-free and renewable deep eutectic solvents（DESs）were designed and used for the deep removal of sulfur dioxide（SO₂）.Firstly,a series of diamine ternary DESs were prepared by regulating the combination of amine substances and the carbon chain length of polyols to test their absorption ability of acidic SO₂ gas.The experimental result demonstrate that as the length of the polyol carbon chain increases,the absorption performance of SO₂decreases accordingly.For the absorption environment of 298.15 K,1.0 bar,and the molar ratio of diethylenetriamine（DETA）:acetamide（AA）:ethylene glycol（EG）equals to 1:1:2,the absorption of SO₂ reaches to 0.82 g SO₂/g DESs（g/g）.Diamine ternary DESs can be regenerated at least 6 times while on the basis of maintaining the highest absorption capacity（0.82 g/g）.According to Fourier-transform infrared spectroscopy（FT-IR）and proton nuclear magnetic resonance（¹H-NMR）,the mainly interaction between diamine ternary DESs and SO₂ is acid-base neutralization.The hydrogen bond formed by ethylene glycol（EG）,acetamide（AA）and SO₂ plays as an auxiliary absorption method.Choline chloride（ChCl）with lower alkalinity and lower toxicity was selected to replace AA to synthesize a series of choline ternary DESs.The relationship between temperature and physical properties（such as density,viscosity,thermal weight loss）,were studied systematically.Then,the required temperature range of the cycle experiment were evaluated through thermodynamics analysis.Under the conditions of298.15 K,1.0 bar,absorption of 0.87 g/g would be achieved for DESs with mole ratio of DETA:ChCl:EG=1:1:2.The absorption balance of choline ternary DESs can be achieved around 50 s.After the absorption,the choline ternary DESs can be regenerated,and it can be reused for at least 5 times,maintaining a high absorption capacity.FT-IR and ¹H-NMR characterizations prove that the nucleophilic Cl^-and SO₂ in the choline ternary DESs forms a strong charge interaction,which would help to promote absorption capacity.Less toxic and soluble imidazole with different alkyl chain length were selected to synthesize imidazole based ternary DESs.The relationship between the alkyl chain length of imidazole ternary DESs and absorption performance for SO₂ was investigated,and it concludes that for DESs with shorter the alkyl chain length,higher absorption capacity would be received.When the molar ratio of DETA:EG:[Emim]Cl equals to2:1:2,the absorption capacity can overtake to 1.02 g/g.The DESs can be regenerated for at least 6 times under 343.15 K,indicating its excellent regeneration performance.FT-IR,¹H-NMR,¹³C-NMR characterization and density functional theory（DFT）calculation indicate that the main reason for the higher absorption capacity of imidazole-based ternary DESs might be ascribed to the existence of multiple absorption sites.更多还原