Activated Carbon Fiber Felts Engineered with Tailored Surface Chemical Properties for Efficient Adsorption of Gaseous Methyl Iodine in Air Condition

Abstract

Gaseous methyl iodine (CH3I) released from nuclear facilities poses a significant threat to human health and the environment. It has been demonstrated that activated carbon materials are effective for the adsorption of gaseous CH3I. However, the conventional granular activated carbons still suffer from some bottleneck problems, including a relative low adsorption rate, inadequate mechanical strength, and limited application flexibility. Alternatively, activated carbon fibers (ACFs) with thinner diameters and high aspect ratio showing high adsorption efficiency to various small molecule pollutants and easy textile processability, are good candidates for the adsorption remove of gaseous CH3I from air, but seldom related works had been carried out. Herein, a functionalized ACF felt with an adsorption capacity of 1331.16 mg/g for gaseous CH3I in air condition was prepared via facilely treating the commercial ACF felt using a vapor deposition method. Polydimethylsiloxane and triethylenediamine (TEDA) were utilized as the hydrophobic modifier and functional impregnating agent. Adsorption kinetics analysis was systematically carried out and the results revealed that the adsorption of gaseous CH3I by the functionalized ACF felt was a complex process that involves not only the physical adsorption of ACFs but also the alkylation reaction (chemisorption) between CH3I and TEDA. With the synergies of functional groups and the developed porous structures, the obtained functionalized ACF felt exhibited a superior CH3I adsorption properties, including comparable adsorption quantities, fast kinetics, and stable fibrous structures, showing good potential for the purification of CH3I-polluted air.

Keywords: activated carbon fiber felts, Hydrophobic treatment, Impregnation modification, Gaseous methyl iodide, adsorption