Protic Ionic-Liquid-Supported Activated Carbon with Hierarchical Pores for Efficient NH₃ Adsorption

Abstract

Ionic liquids (ILs) provide a new way for efficient separation and recovery of NH3 because of low vapor pressure and adjustable properties. However, high viscosity or solid state of functionalized ILs at ambient temperature makes them impossible to use in traditional scrubbing processes. Therefore, combining ILs with porous solid materials to form novel IL-supported materials for NH3 adsorption is an effective method to solve the above problem. In this work, three protic ILs (PILs) including imidazolium bis­(trifluoromethylsulfonyl)­imide ([Im]­[NTf2]), 1-methylimidazolium bis­(trifluoromethylsulfonyl)­imide ([1-Mim]­[NTf2]), and 2-methylimidazolium bis­(trifluoromethylsulfonyl)­imide ([2-Mim]­[NTf2]) were supported onto activated carbon (AC) to prepare PIL-supported materials. The effects of PILs and AC types, PIL loadings, temperatures, and partial pressures on NH3 adsorption, as well as the recyclability of the PIL-supported materials, were investigated in detail. Among the investigated PIL-supported materials, 20 wt % [2-Mim]­[NTf2]-supported AC-980 exhibits the higher capacity of 68.61 mg of NH3/g of adsorbent at 303.15 K and 0.10 MPa with good NH3 selectivity and fast adsorption rate because of the synergistic interaction of hydrogen bonding between the PIL and NH3 and hierarchical pores, which is 30% higher than that of pure AC. Meanwhile, the PIL-supported material shows good recyclability after five cycles, implying great potentials for NH3 separation industrial processes.

Highly Dispersed Ionic Liquids in Mesoporous Molecular Sieves Enable a Record NH3 Absorption

“…The high dispersion of ILs in stable porous adsorbents prepared by impregnation is a simple and efficient approach to construct high-efficiency hybrid adsorbents with more exposed active sites. , In this context, IL hybrid carbon- − and silicon-based , adsorbents have been reported for NH 3 uptake. Because of the pore blockage of the parent porous materials by the large volume of IL and weak interaction between IL and NH 3 , the adsorption performance of these IL hybrid adsorbents needs to be further improved.…”

Control of Functionalized Pore Environment in Robust Ionic Ultramicroporous Polymers for Efficient Removal of Trace Propyne from Propylene

“…Traditional cryogenic distillation suffers from intensive consumption of energy and high cost . Highly efficient and energy-saving adsorptive separation based on porous materials is very attractive for industrial gas separation and purification. − However, similar molecular dimensions (C 3 H 4 : 4.52 × 4.02 × 6.61 Å 3 ; C 3 H 6 : 5.25 × 4.16 × 6.44 Å 3 ) and physicochemical properties of C 3 H 4 and C 3 H 6 make their separation a great challenge, especially for high deep removal of low C 3 H 4 content. , …”

Protic ionic liquid‐based deep eutectic solvents with multiple hydrogen bonding sites for efficient absorption of NH3

“…Ammonia (NH 3 ) is an important chemical raw material, especially in nitrogenous fertilizers and nitric acid 1,2 . However, NH 3 -containing gases released to air by fertilizer industries, fossil fuel combustion, refrigeration processes and so on [3][4][5] , also cause serious environmental issues by combining with NO x or SO x in atmosphere to form ammonium salts, a main component of PM2.5 (Particulate Matter 2.5) [6][7][8][9] .…”