Low Pressure CO2 Capture with Amide-Based Imprinted Polymers

Abstract

Bulk polymerization was used to fabricate molecularly imprinted polymer (MIP) adsorbents inherent with amine-functionality for post combustion CO2 capture. Polymerization was performed at 333 K for 24 hours using methacrylamide and ethylene glycol dimethacrylate (EGDMA) as the functional monomer and cross linker respectively, oxalic acid as the template azobisisobutyronitrile (AIBN) as the initiator and 4:1 (v/v) mixture of acetonitrile and dimethylformamide (DMF) as the porogenic solvent. The monolithic polymers were crushed and ground, followed by screening to 75-215 μm and the template was then removed from the polymeric particles by extraction using methanol and hydrochloric acid (90/10 v/v). A fixed bed adsorption column was used to investigate the performance of the dynamic CO2 uptake capacities. The X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared spectroscopy (FT-IR) spectra showed a huge number of -NH2 functionality distributed on the surface of the adsorbents, which thus enhanced the CO2 adsorption uptake. The maximum CO2 capture capacity was found in the MIP with the maximum template concentration (0.40 mmol/g, SBET 258 m2/g at 0.15 bar partial pressure and temperature of 313 K). The MIPs were stable thermally up to 518 K and the isotherms displayed type II revealing a non-uniform distribution of the pore size.