Adsorption and desorption of gaseous methyl iodide in a triethylenediamine-impregnated activated carbon bed

Sorption Properties of Activated Carbons for the Capture of Methyl Iodide in the Context of Nuclear Industry

“…Taking into ac count only the computed adsorption capacities values, the non impregnated activated carbon (AC1 -G) seems to display the best adsorption performance towards CH3 I in the first set of conditions. This behavior is in line with literature studies [36,48,49] considering similar conditions in terms of temperature, relative humidity and concentrations. Indeed, it has been reported that adsorp tion is mainly governed by physisorption at low temperatures, dry atmosphere and at high adsorbate concentrations [9,36,4 8,49].…”

“…More precisely, it was reported [56] that the adsorbed water molecules formed clusters interacting through hydrogen bonds with activated carbon porous network, making therefore the ac tive sites less accessible for iodine species. On the other hand, the global adsorption capacities decrease is reported by several studies for increasing temperature owing to the reduction of physisorption phenomena, which are promoted preferentially at low temperatures [36,49]. More particularly, the study of Park et al [49] have reported a progressive decrease in the fraction of physisorbed CH3 I by an impregnated AC (6.5 wt% of TEDA) from 58% to 34% for temperatures ranging from 35 to 75 °C.…”

“…before KI and TEDA impregnation). Nevertheless, pore blockage phenomena are known to occur upon impregnation due to the presence of the incorporated agents within or at the micropores openings [9,12,16,36,37].…”

Porous sorbents for the capture of radioactive iodine compounds: a review

“…However, non-impregnated activated carbon loses adsorption efficiency when the temperature rises (weak physisorption interaction). Moreover, it can be noted that at low temperatures (30 °C) non-impregnated activated carbon possesses adsorption capacities that are as good as, if not even better than, those when impregnated with TEDA (Park et al 67,73 and González-García et al 147 ). TEDA was able to counterbalance the detrimental effect of humidity on the adsorption capacities of activated carbons by freeing the active sites of the support (water has a stronger affinity for TEDA than for the active sites).…”

Universal Scaling Relationship To Screen an Efficient Metallic Adsorbent for Adsorptive Removal of Iodine Gas under Humid Conditions: First-Principles Study

“…For instance, activated carbons with a tertiary amine and various kinds of metals as impregnants are commercialized adsorbents to capture radioactive organic iodine gases. It was known that the tertiary amines undergo chemical reactions with methyl iodide to form a quaternary ammonium salt under humid conditions. ,− The activated carbons, however, have low ignition temperatures and risks to explode. Li et al reported a tunable crystalline porous material, a metal–organic framework (MOF), by introducing amine functional groups to overcome the limitations of the activated carbon adsorbents. , Moreover, functionalized solid adsorbents such as cation-exchanged mordenites or MOFs with open metal sites that have high affinity toward iodine species have been extensively studied because of their excellent performance for removing iodine gases. − Most of the technologies rely on selective stronger interactions of the impregnants, such as triethylenediamine (TEDA) or silver, with iodine than other gases (such as hydrogen or CO 2 ). , High material cost of silver impregnants, however, remains problematic in wider applications of the materials…”