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地球环境中普遍存在的纳米孔与有机质的相互作用对资源和环境领域许多重要科学问题(如有机质的吸附与保存、油气的赋存与采收以及二氧化碳的地质封存等)起着关键作用。然而,目前关于纳米孔特别是微孔(<2 nm)与有机质作用的系统研究还比较少。本文选择实验室合成的Stber二氧化硅作为模拟矿物微孔,采用热红联用技术(TG/DSC-FTIR)来研究其与系列有机溶剂(乙醇、正丙醇、正丁醇、正庚醇)作用后的热化学性质。结果表明,乙醇和正丙醇较易进入Stber二氧化硅微孔(孔径0.8 nm)。在NH_3催化作用下,醇与孔内外硅羟基发生烷氧基化作用,孔外烷氧基的脱除温度随着溶剂碳链增加而降低,放热效应逐渐增强;相反,孔内烷氧基的脱除温度随碳链增加而增加,放热效应逐渐减弱。在无NH_3存在条件下,由于烷氧基化作用减弱,乙醇与正丙醇能在孔内游离存在,孔内烷氧基的脱除温度随溶剂碳链增加呈下降趋势。Stber二氧化硅的微孔结构直接影响了醇类有机质在不同气氛下的热解行为,甲烷、乙烯、丙醛等分子的逸出也为纳米孔隙结构束缚下的有机质的深部热行为提供了参考。
The ubiquitous interaction between nanopores and organic matter in the Earth’s environment plays a key role in many important scientific issues in the area of resources and the environment, such as the adsorption and preservation of organic matter, the occurrence and recovery of hydrocarbons and the geological storage of carbon dioxide. However, there are still few systematic studies on the interaction between nanopores, especially micropores (<2 nm) and organic matter. In this paper, the Stöber silica synthesized in laboratory was chosen as the simulated microwell. The thermal red combination technique (TG / DSC-FTIR) was used to study the interaction between organic solvents (ethanol, n-propanol, n-butanol, Heptanol) after the thermochemical properties. The results show that Ethanol and n-propanol are more accessible to Stber silica micropores (pore size 0.8 nm). Under the NH_3 catalysis, the alkoxylation of silanols with the inside and outside of the hole occurred. The removal temperature of the alkoxy groups outside the hole decreased with the increase of the solvent carbon chain, and the exothermic effect gradually increased. On the contrary, Removal temperature increases with increasing carbon chain, the exothermic effect gradually weakened. In the absence of NH 3, ethanol and n-propanol can exist in the pores due to the weakening of alkoxylation, and the removal temperature of alkoxy in the pores decreases with the increase of solvent carbon chain. The microporous structure of Stber silica directly affects the pyrolysis behavior of alcohols in different atmospheres. The escape of molecules such as methane, ethylene and propionaldehyde is also provided by the deep thermal behavior of the organic matter bound by the nanoporous structure For reference.