Standeker Suzana, Novak Zoran, Knez Zeljko
Faculty of Chemistry and Chemical Engineering, University of Maribor, Maribor, Slovenia.
J Hazard Mater. 2009 Jun 15;165(1-3):1114-8. doi: 10.1016/j.jhazmat.2008.10.123. Epub 2008 Nov 11.
Silica aerogels are alternative adsorbents to activated carbon (AC) for the removal and the recovery of organic vapours from gas streams. The adsorption capacity measurements of different silica aerogels were done by mini-column method. Continuous adsorption measurements show that silica aerogels are excellent adsorbents of BTEX vapours from waste gas stream. Compared to the most used adsorbents, such as AC and silica gel, aerogels exhibit capacities which enormously exceed that of both commonly used adsorbents. By increasing the degree of hydrophobicity, aerogels become less effective, but they do not adsorb water vapour from gas stream. Silica monolith aerogels with different degrees of hydrophobicity by incorporating methyltrimethoxysilane (MTMS) or trimethylethoxysilane (TMES) in standard sol-gel synthesis were prepared. Excellent properties of aerogels, obtained with the sol-gel synthesis, were preserved with supercritical drying with CO(2). The degree of hydrophobicity of the aerogels was tested by measuring the contact angle (theta) of a water droplet with the aerogel surface. The aerogels were also characterised by FTIR, nitrogen sorption and DSC/TG measurements.
二氧化硅气凝胶是用于从气流中去除和回收有机蒸汽的活性炭（AC）替代吸附剂。通过微型柱法对不同二氧化硅气凝胶的吸附容量进行了测量。连续吸附测量表明，二氧化硅气凝胶是废气中BTEX蒸汽的优良吸附剂。与最常用的吸附剂（如AC和硅胶）相比，气凝胶的吸附容量大大超过了这两种常用吸附剂。通过增加疏水性程度，气凝胶的效果会变差，但它们不会从气流中吸附水蒸气。通过在标准溶胶 - 凝胶合成中加入甲基三甲氧基硅烷（MTMS）或三甲基乙氧基硅烷（TMES）制备了具有不同疏水性程度的二氧化硅整体气凝胶。溶胶 - 凝胶合成获得的气凝胶的优异性能通过用CO₂超临界干燥得以保留。通过测量水滴与气凝胶表面的接触角（θ）来测试气凝胶的疏水性程度。气凝胶还通过傅里叶变换红外光谱（FTIR）、氮吸附和差示扫描量热法/热重分析法（DSC/TG）进行了表征。
