Alkane Adsorption on Microporous SiO₂ Substrata. 1. Textural Characterization and Equilibrium

Abstract

Microporous silica solids of SiO 2 and Ag/SiO 2 (a microporous SiO 2 substrate containing 5 wt % Ag) are synthesized by the sol-gel method and analyzed through several characterization techniques. The type I shapes of N 2 sorption isotherms at 76 K on these materials indicate large micropore contents as well as important cohesive interactions between adsorbed N 2 molecules, i.e., a gradual cooperative filling process becomes more and more evident as the concentration of adsorbate within the porous structure increases. In addition, negative values of the BET constant are found thus indicating that the adsorption mechanism on these solids can be better described in terms of a volume filling process rather than in terms of a multilayer formation phenomenon. The microporosity existing in these substrata is studied through Sing's R s -plots. The adsorption capacities of n-alkanes (i.e. n-hexane, n-heptane, n-octane, and n-nonane) on SiO 2 and Ag/SiO 2 substrata are measured by gas chromatography (GC) at different temperatures. The uptake of every hydrocarbon sorptive, on both SiO 2 and Ag/SiO 2 substrata, is found to be temperaturedependent. Additionally, the intensities of attractive interactions between hydrocarbon ad molecules and the surfaces of the above solids are evaluated for each adsorbate type from determinations of the isosteric heats of adsorption.

Adsorption of benzene, cyclohexane and hexane on ordered mesoporous carbon

“…Volatile organic compounds (VOCs) are a class of air pollutants in industrial processes and daily human consumption Parmar and Rao, 2009;He et al, 2012;Hernandez et al, 2003;Ghoshal and Manjare, 2002;Reguer et al, 2011;Gonzalez-Miquel et al, 2013). Because of their high vapor pressure and low boiling point, they are prone to be emitted into the atmosphere, causing great environmental problems because of their intrinsically hazardous properties.…”

“…Because of their high vapor pressure and low boiling point, they are prone to be emitted into the atmosphere, causing great environmental problems because of their intrinsically hazardous properties. Not only they are the main precursors of photochemical reaction in the atmosphere, inducing ozone destruction and photochemical smog, but they are also toxic toward human health, and may cause pathogenic, mutagenic and even fatal diseases (Wang et al, 2007;Parmar and Rao, 2009;He et al, 2012;Hernandez et al, 2003). Unfortunately, with the continuous development of industrialization in recent years, the emissions of VOCs have gradually increased to a new high level (Ghoshal and Manjare, 2002;Wu et al, 2011).…”

“…Various kinds of methods, such as catalytic oxidation, adsorption, absorption, photocatalytic processes, and biological methods are employed for the abatement of VOCs (Wang et al, 2007;Parmar and Rao, 2009;He et al, 2012;Hernandez et al, 2003;Ghoshal and Manjare, 2002;Reguer et al, 2011;Gonzalez-Miquel et al, 2013). Among them, adsorption technology seems to be the preferred choice due to its great advantages of convenience and high efficiency (Hernandez et al, 2003;Ghoshal and Manjare, 2002;Reguer et al, 2011).…”

Adsorption and separation of linear and branched alkanes on carbon nanotube bundles from configurational-bias Monte Carlo simulation

“…Yun et al 12 reported the adsorption of the C 1 and C 2 alkanes, and their binary mixtures on hexagonally ordered MCM-41, and validated methods for the prediction of adsorption equilibrium. Hernandez et al 13 measured the adsorption capacities of the linear C 6 ,C 7 ,C 8 , and C 9 alkanes on microporous silica solids at different temperatures, and found the limiting adsorption energy to be more attractive for a longer alkane.…”

Study of the Influence of Pore Width on the Disposal of Benzene Employing Tunable OMCs

“…Recently, Yuan et al 20 studied the adsorption and separation properties of CO 2 , N 2 , and CH 4 on OMC. The results revealed that OMC has high adsorption capacities for CO 2 and CH 4 and high selectivities for CO 2 /CH 4 , CH 4 /N 2 , and CO 2 /N 2 mixtures simultaneously. All of the relevant research results confirm the superior adsorption properties of OMCs.…”