Removal of Hydrogen Sulfide and Sulfur Dioxide by Carbons Impregnated with Triethylenediamine

Abstract

Activated carbon (AC) adsorption has long been considered to be a readily available technology for providing protection against exposure to acutely toxic gases. However, ACs without chemical impregnation have proven to be much less efficient than impregnated ACs in terms of gas removal. The impregnated ACs in current use are usually modified with metalloid impregnation agents (ASC-carbons; copper, chromium, or silver) to simultaneously enhance the chemical and physical properties of the ACs in removing specific poisonous gases. These metalloid agents, however, can cause acute poisoning to both humans and the environment, thereby necessitating the search for organic impregnation agents that present a much lower risk. The aim of the study reported here was to assess AC or ASC-carbon impregnated with triethylenediamine (TEDA) in terms of its adsorption capability for simulated hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) gases. The investigation was undergone in a properly designed laboratory-scale and industrial fume hood evaluation. Using the system reported here, we obtained a significant adsorption: the removal capability for H 2 S and SO 2 was 375 and 229 mg/g-C, respectively. BET measurements, element analysis, scanning electron microscopy, and energy dispersive spectrometry identified the removal mechanism for TEDA-impregnated AC to be both chemical and physical adsorption. Chemical adsorption and oxidation were the primary means by which TEDA-impregnated ASC-carbons removed the simulated gases.

Impregnated Activated Carbon Materials for Respiratory Purpose. Chemisorption of Sulfur Dioxide

“…According to [102], increasing the potassium iodide content of AC-KI to 16% improves its protective properties against SO 2 (τ pa (SO 2 )) according to equation (5); then when ωKI increases to 22%, this characteristic approaches an almost horizontal asymptote, after which it sharply decreases. This indicates that at high contents, KI (like K 2 CO 3 [5], 1,8-diazobicyclooctane (DABCO) [106], triethanolammonium citrate (1:3) [107]) aggregates and/or blocks AC pores, which limits the accessibility of I 2 for SO 2 . Along with this, increasing the KI content lowers the sorption capacity of KI with respect to C 6 H 6 according to equation (6): where τ pa (SO 2 ) is the time of the protective action against SO 2 (min) at СSO 2 = 150 mg/m 3 , a relative humidity of the GAM of 90-95%, a flow rate of the GAM of 2.0 cm/s; τ pa (C 6 H 6 ) is the time of protective action against C 6 H 6 (min) at С 6 H 6 = 500 mg/m 3 , a relative humidity of the GAM of 90-95%, a flow rate of the GAM of 2.0 cm/s); ωKI is the mass fraction of KI, %.…”

“…To remove acidic gaseous pollutants, IAC materials based on impregnating solutions of N-containing organic bases are used: monoethanolamine (MEA) [108][109][110][111], diethanolamine (DEA) [109,110,112], triethanolamine (TEA) [113], DABCO [14,106,112,[114][115][116], N-methyldiethanolamine (MDEA) [118], pipe razine [111], etc., similarly to [119,120]. IACs based on N-containing organic bases are also widely used for the sanitary removal of formaldehyde from the air [121].…”

Selective capture of trace sulfur gas by porous covalent-organic materials

“…Aqueous solutions of alkanolamines are commonly used to remove H 2 S, but they cannot reduce the sulfur content to the low levels required (Xu et al, 2005). Among the methods used to remove low concentration H 2 S/SO 2 from mixture gases, adsorption by porous materials such as activated carbons (AC) (Bagreev and Bandosz, 2001;Bandosz, 1999;Guo and Lua, 2002), ammonia-treated activated carbon fibers (Mangun et al, 2001), impregnated activated carbon (Bandosz et al, 2000;Wu et al, 2007;Xiao et al, 2008), zeolites (Cosoli et al, 2008;Melo et al, 2006), metal organic frameworks (MOFs) (Hamon et al, 2009;Xiang et al, 2011), is an efficient and economical approach. For example, Cosoli et al (2008) simulated H 2 S removal from biogas by zeolites and confirmed that hydrophilic zeolites are more suitable for H 2 S adsorption.…”