Abstract
Carbon-silica composites with nanoporous structures were synthesized for the adsorption of volatile organic compounds (VOCs), taking tetraethyl orthosilicate (TEOS) as the silicon source and activated carbon powder as the carbon source. The preparation conditions were as follows: the pH of the reaction system was 5.5, the hydrophobic modification time was 50 h, and the dosage of activated carbon was 2 wt%. Infrared spectrum analysis showed that the activated carbon was dispersed in the pores of aerogel to form the carbon-silica composites material. The static adsorption experiments, dynamic adsorption-desorption experiments, and regeneration experiments show that the prepared carbon-silica composites have microporous and mesoporous structures, the adsorption capacity for n-hexane is better than that of conventional hydrophobic silica gel, and the desorption performance is better than that of activated carbon. It still has a high retention rate of adsorption capacity after multiple adsorption-desorption cycles. The prepared carbon-silica composites material has good industrial application prospects in oil vapor recovery, providing a new alternative for solving organic waste gas pollution.
Highlights
The volatile organic compounds (VOCs) refer to organic compounds with the saturated vapor pressure of more than 70 Pa at room temperature, the boiling point of less than 260 ◦ C at normal pressure, and they are usually present in the form of vapor in the air at normal temperature [1]
Motivated by the conclusion that carbon-silica composites have good adsorption property and excellent regeneration performance from the above discussions, we reported the preparation of carbon-silica composites by the traditional sol-gel method, taking tetraethyl orthosilicate (TEOS) as the silicon source and activated carbon powder as the carbon source [25]
The preparation scheme of the carbon-silica composites material is as follows: adding activated carbon powder during the preparation of the aerogel though sol-gel method, giving hydrophobic properties to the composites materials by methylation reaction and thereby obtaining nano-porous carbon-silica composites adsorbent for VOCs adsorptions
Summary
The volatile organic compounds (VOCs) refer to organic compounds with the saturated vapor pressure of more than 70 Pa at room temperature, the boiling point of less than 260 ◦ C at normal pressure, and they are usually present in the form of vapor in the air at normal temperature [1]. The advantages (such as the noncombustibility and the high regeneration rate of the hydrophobic silica gel and the large adsorption capacity of the activated carbon) can be comprehensively utilized, while the disadvantages (such as the limited adsorption capacity of the hydrophobic silica gel and the poor regeneration property of the activated carbon) can be overcame [20,21] This adsorbent composite system based on the adsorption bed filling technology enables many chemical enterprises to meet the previous requirement that the total emission of non-methane hydrocarbon should be less than 0.5 g per liter of gasoline, which was issued earlier by the Ministry of Environment Protection of the People’s Republic of China. Due to the complex composition of oil vapor and the different volatility of each component, n-hexane, which accounts for a large proportion of oil vapor and has moderate volatility, was selected as the adsorbent for oil vapor adsorption capacity evaluation tests [26]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
