TMCS/PTES改性制备疏水硅胶及其正戊烷/正己烷吸附性能研究

doi:10.15541/jim20260129

摘要/Abstract

摘要： 水汽在硅胶(SG)中引发的竞争吸附严重制约了其在高湿度条件下的应用。本研究利用三甲基氯硅烷(TMCS)和苯基三乙氧基硅烷(PTES)对SG进行改性, 通过一系列表征手段探究材料的物理和化学特性, 结合动态吸附平衡实验和原位红外光谱实验探究吸附材料对正戊烷和正己烷的吸附性能。结果表明：改性后的硅胶抗湿性明显增强, TMCS改性时, 其达到阈值浓度后, 改性硅胶的孔结构参数不再发生变化, 17%(体积分数)TMCS的改性硅胶(SG-17%-TMCS)接触角达130.8°, 总孔容保持率高达96.6%; PTES改性受多方面因素的共同影响, 其中pH和温度影响较大, 100%(体积分数)TMCS的改性硅胶(SG-100%-PTES)接触角达137.4°, 但比表面积和孔容显著下降至153 m²/g和0.061 cm³/g。吸附结果表明：TMCS改性硅胶在高湿条件下仍能保持较好的正戊烷和正己烷吸附能力, 且其相对优势随湿度升高进一步凸显, 5次高湿条件下吸脱附循环后对正戊烷和正己烷的容量保持率分别维持在约90%和92%; PTES改性硅胶由于自身孔道结构的限制和分子空间位阻效应, 吸附性能下降。本研究阐明了改性条件对TMCS和PTES改性硅胶疏水性能的影响及改性后材料对正戊烷和正己烷的吸附作用, 为高湿废气中正戊烷和正己烷的高效脱除与回收提供了理论参考。

关键词: 疏水改性, 孔结构调控, 空间位阻, 竞争吸附

Abstract: Competitive adsorption induced by water vapor severely restricts the application of silica gel under high-humidity conditions. In this study, silica gel was hydrophobically modified using trimethylchlorosilane (TMCS) and phenyltriethoxysilane (PTES). Physicochemical properties of the synthesized materials were evaluated by various characterization techniques. Additionally, adsorption performance towards n-pentane and n-hexane was assessed by dynamic adsorption equilibrium experiments coupled with in-situ infrared spectroscopy. Results indicate that the modified silica gels exhibit significantly enhanced moisture resistance. TMCS modification is highly concentration-dependent, and pore structural parameters of the modified silica gel remain constant after reaching the threshold concentration. The optimal sample modified by 17% (in volume) TMCS (SG-17%-TMCS) achieves a contact angle of 130.8° and retains 96.6% of its total pore volume. Conversely, PTES modification depends on multiple interacting factors, with pH and temperature exerting the most significant impacts. The optimal PTES-modified (100%, in volume) sample exhibits a contact angle of 137.4°, but its specific surface area and pore volume decrease markedly to 153 m²/g and 0.061 cm³/g. Adsorption tests reveal that the TMCS-modified silica gel maintains high adsorption selectivity for n‑pentane and n‑hexane even under high-humidity conditions, and its performance advantage expands further as humidity increases. After five adsorption-desorption cycles under high humidity, the capacity retention rates for n-pentane and n-hexane remain at approximately 90% and 92%. In contrast, adsorption capacity of the PTES-modified silica gel decreases due to severe limitations imposed by its altered pore structure and pronounced molecular steric hindrance. This study elucidates how modification conditions affect the hydrophobicity of TMCS- and PTES-modified silica gels, alongside their consequent adsorption behaviors towards n‑pentane and n‑hexane. These findings provide a solid theoretical reference for the efficient removal and recovery of n‑pentane and n‑hexane from high-humidity exhaust gases.

Key words: hydrophobic modification, pore structure regulation, steric hindrance, competitive adsorption

中图分类号:

TQ424

罗宇浩, 冯廷雪, 杨立辉, 董彦超, 刘娜, 黄雪莉, 黄河. TMCS/PTES改性制备疏水硅胶及其正戊烷/正己烷吸附性能研究[J]. 无机材料学报, DOI: 10.15541/jim20260129.

LUO Yuhao, FENG Tingxue, YANG Lihui, DONG Yanchao, LIU Na, HUANG Xueli, HUANG He. Hydrophobic Silica Gel Modified by TMCS/PTES: Preparation and Its n‑Pentane/n‑Hexane Adsorption Performance[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260129.

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