Adsorption and desorption performance of benzene over hierarchically structured carbon–silica aerogel composites

Abstract

a b s t r a c tHierarchically structured carbon-silica aerogel (CSA) composites were synthesized from cheap water glass precursors and granulated activated carbon via a post-synthesis surface modification with trimethylchlorosilane (TMCS) and a low-cost ambient pressure drying procedure. The resultant CSA composites possess micro/mesoporous structure and hydrophobic surface. The adsorption and desorption performance of benzene on carbon-silica aerogel composite (CSA-2) under static and dynamic conditions were investigated, comparing with pure silica aerogel (CSA-0) and microporous activated carbon (AC). It was found that CSA-2 has high affinity towards aromatic molecules and fast adsorption kinetics. Excellent performance of dynamic adsorption and desorption observed on CSA-2 is related to its higher adsorption capacity than CSA-0 and less mass transfer resistance than AC, arising from the well-developed microporosity and open foam mesostructure in the CSA composites.

Benzene and Methane Adsorption on Ultrahigh Surface Area Carbons Prepared from Sulphonated Styrene Divinylbenzene Resin by KOH Activation

“…Ramirez et al (2005) investigated adsorption of benzene vapour on activated carbons and activated carbon fibres and reported gas uptakes of approximately 400 mg g -1 and approximately 600 mg g -1 , respectively. Dou et al (2011) reported similar data for an activated carbon BN-09 < 60 mesh manufactured by Ningxia Benniu Activated Carbon Works, which adsorbed approximately 400 mg g -1 of benzene at 25 °C and 120 mbar. Taba (2009) compared benzene adsorption on an activated carbon Norit SX22 and a mesoporous carbon CMK-1 and found that the latter adsorbs approximately 800 mg g -1 , whereas the former only approximately 400 mg g -1 .…”

A hierarchically porous diatomite/silicalite-1 composite for benzene adsorption/desorption fabricated via a facile pre-modification in situ synthesis route

“…However, its poor thermal stability and limited modification flexibility prevent its industrial application in VOC adsorption. In addition, it is difficult to regenerate the active material because the organic gas molecules adsorbed in the slit-like micropores of activated carbon are difficult to desorb [12]. Silicalite-1, the most well-known aluminum-free MFI-type zeolite, exhibits a significant adsorption capacity for VOCs because of its abundance of microporous structures with high specific surface areas and well-developed hydrophobicity [13,14]; in particular, silicalite-1 nanoparticles, are characterized as having high thermal and chemical stabilities and favorable reusability.…”

“…Fletcher et al [39,40] investigated the adsorption-desorption kinetics for vapors on activated carbon. Dou et al [12] reported the mass transfer efficiency of benzene over carbon-silica composites. However, to date, few reports have systematically investigated the mass transfer efficiency of diatomite/zeolite composites, and there are no related reports regarding their reusability.…”

Fast Detection and Chemical Characterization of Gunshot Residues by CMV-GC-MS and LIBS

“…The detection of volatile organic compounds (VOCs) present in ambient air is of great concern because of the potential hazards to human health and the environment [Dou et al, 2011;Wong et al, 2013]. The Environmental Protection Agency (EPA) has created an extensive list of compounds that have been reportedly detected in areas where air pollution is suspected such as, industrial sites [EPA .…”

“…The Environmental Protection Agency (EPA) has created an extensive list of compounds that have been reportedly detected in areas where air pollution is suspected, such as industrial sites . Many of the compounds present in ambient air have the potential to act as mutagens and carcinogens [Wong et al, 2013;Dou et al, 2011]. Therefore, there is the need for the detection, monitoring, and quantitation of VOCs in ambient air.…”