Ammonia capture from the gas phase by encapsulated ionic liquids (ENILs)

Abstract

Encapsulated ionic liquids (ENILs) based on carbonaceous submicrocapsuleswere designed, synthesized and applied to the sorption of NH 3 from gas stream. The ENILs were prepared using three different task-specific ILs with adequate properties for NH 3 capture: 1-2(-hydroxyethyl)-3-methylimadazolium tetrafluoroborate (EtOHmimBF 4 ), choline bis(trifluoromethylsulfonyl)imide (CholineNTf 2 ) and tris(2hydroxyethyl)-methylammoniummethylsulfate [(EtOH) 3 MeNMeSO 4 ]. The ENILs synthesized were analyzed by different techniques to assess their morphology, chemical composition, porous structure and thermal stability. The capture of NH 3 was tested in fixed-bed experiments under atmospheric pressure. The influence of the type and load of IL, temperature (30, 45 and 60 ºC) and NH 3 inlet concentration was analyzed.Desorption of NH 3 from the exhausted ENILs was also studied at atmospheric pressure and temperatures in the range of 150 to 200 ºC. The ENILs prepared with task-specific ILs were found to be suitable for NH 3 capture in the fixed-bed operation. These systems can be a promising alternative to conventional absorption or adsorption due to: i) high sorption capacity controlled by IL selection, ii) remarkable mass transfer rate, iii) low 2 sensitiveness to high temperatures of the gas stream, iv) fast and complete regeneration of the exhausted ENIL at mild conditions; and v) recovery of NH 3 .

Encapsulated Ionic Liquids for CO2 Capture: Using 1‐Butyl‐methylimidazolium Acetate for Quick and Reversible CO2 Chemical Absorption.

“…Therefore, the discretization of [bmim][acetate] through encapsulation into C cap barely affects its CO 2 absorption capacity. Similar results were achieved in a previous work, in which other ENILs prepared with task‐specific ILs were tested in NH 3 capture from gas effluents . As in the case of CO 2 absorption with [bmim][acetate], increasing the temperature reduced the retention of CO 2 by the ENIL, whereas the increase of the partial pressure of CO 2 implied a significant increase of the CO 2 uptake .…”

“…Nanocomposites of ILs confined in mesoporous silica gels were successfully applied to the selective sorption of CO 2 /N 2 streams . We recently presented ENIL materials consisting of hollow carbonaceous submicrocapsules (C cap , particle diameter >400 nm) able to confine high amounts of IL (70–85 % w/w). This ENIL material has been used previously in NH 3 gas sorption process, demonstrating that it preserves the solvent capacity of ILs but drastically enhances the rate of mass transfer by increasing the specific contact area, upon the discretization of the IL fluid by its encapsulation in submicrodrops.…”

Absorptive Desulfurization of Model Biogas Stream Using Choline Chloride-Based Deep Eutectic Solvents

“…Consequently, the absorption process can be performed at room temperature with minimal energy consumption. Similar results were obtained at work [55].…”

Encapsulated Amino‐Acid‐Based Ionic Liquids for CO2 Capture

“…The carbon submicrocapsules ( C c ap ) were synthesized following the template method described in detail in previous works , , , , , . A model of a silica sphere with a solid core and mesoporous shell were used as template.…”

“…Nonetheless, many have pursued different approaches aiming at minimizing these limitations, while maintaining the enhanced gas sorption capacity, such as using a solid phase to immobilize the solvents and the use of gas‐liquid membrane contactors for gas absorption processes , . Recently, the confinement of solvents in nano‐porous matrices has been proposed as a promising technique for gas separation, with improved mechanical integrity capable of overcoming the major drawbacks of the bulk solvents, such as high viscosity and slow gas diffusivity, and ultimately, requiring reduced quantities of solvent to achieve the separation , . The encapsulated ionic liquids (ENILs) have shown to impose no loss of the solvent absorbent capacity with a drastic enhancement of the CO 2 sorption rate, both for physical or chemical sorption driven solvents , , , …”