Development of Ionic Liquids Tethered to Coconut Shell Activated Carbon for Biogas Upgrading in a Packed Bed

Abstract

Ionic liquids (ILs) were prepared in situ successfully on coconut shell activated carbon (AC) granules for biogas upgrading in a packed bed. In biogas upgrading, the saturated CO2 capture capacities of AC‐tethered 1‐butyl‐3‐propylimidazolium bis(trifluoromethylsulfonyl)imide (AC‐[BPIM][Tf2N]) and AC‐tethered 1‐aminoethyl‐3‐propylimidazolium bis(trifluoromethylsulfonyl)imide (AC‐[EPIM‐NH2][Tf2N]) were 2.58 and 2.95 mmol g−1 at 20 °C and 0.5 MPa, respectively. The heat of adsorption was 23–28 kJ mol−1 for AC‐[BPIM]‐based adsorbents and 65–71 kJ mol−1 for AC‐[EPIM‐NH2]‐based ones. As a CO2 concentration of less than 3 % is required for biogas to be used in a vehicle, an adsorption capacity at which 3 % of CO2 is reached in the upgraded gas could be more important. If the flow rate of the inlet gas was 50 mL min−1, the adsorption capacity at which 3 % of CO2 is reached in the upgraded gas was 1.44 mmol g−1 for AC‐[BPIM][Tf2N] and 1.95 mmol g−1 for AC‐[EPIM‐NH2][Tf2N] at 20 °C and 0.2 MPa. The adsorption selectivities of CO2 over CH4 were ∼92 and 95 % for AC‐[BPIM][Tf2N] and AC‐[EPIM‐NH2][Tf2N], respectively. The immobilized ILs exhibited a relatively stable cyclability in a packed bed.

Synthesis of polyamino styrene from post-consumption expanded polystyrene and analysis of its CO2 scavenger capacity

“…Other wastes as coffee ground biochar (Liu and Huang 2018), petroleum coke (Shin et al 2017), coconut shell (Wang et al 2015) and plastics like PVC (Sneddon et al 2017), highly porous PS (Zainab et al 2018) and polyurethane (Ge et al 2016) have been employed as CO 2 adsorbents as well.…”