Polyethyleneimine functionalised nanocarbons for the efficient adsorption ofcarbon dioxide with a low temperature of regeneration

Abstract

Polyethyleneimine (PEI) conjugates with a range of nanocarbons (NCs) have been prepared, and their performances with regard to carbon dioxide absorption and liberation are compared. PEI-functionalised multi-walled carbon nanotubes (PEI-MWNTs) prepared by the reaction of branched PEI (25,000 Da) with F-MWNTs in the presence of pyridine, showed a lower CO 2 capacity at 25 C (5 wt%, 1.1 mmol CO 2 /g adsorbent) as compared to PEI-SWNTs (9.2 wt%, 2.1 mmol CO 2 /g adsorbent), consistent with the interior layers of the MWNTs adding weight to the base NC without adding functionality. PEI-functionalised graphite/graphene was prepared by three routes: fluorinated graphite intercalation compounds, prepared from natural graphite powder, were reacted with PEI in EtOH with pyridine; exfoliated natural graphite powder was reacted with Boc-Phe(4-N 3 )-OH, and subsequently PEI to give PEI-Phe(4-N-G); graphite oxide (GO) was reacted with PEI in the presence of NEt 3 to give PEI-GO. The CO 2 capacity of PEI-GO at 25 C (8 wt%, 1.8 mmol CO 2 /g adsorbent) was comparable to that of PEI-SWNTs making GO a valid and cheaper alternative to the SWNT scaffold. The temperature of CO 2 desorption of the PEINCs was 75 C, providing a lower energy load for regeneration compared to current amine-based scrubbing units. The rate of CO 2 uptake is seen to depend on the curvature of the NC substrate.

Improvement of CO2 capture by graphite oxide in presence of polyethylenimine

“…A peak associated with CeN is observed at 399.38 eV; this corresponds to nitrogen atoms in the amine groups of polyethylenimine. Through the XPS results, this is confirmative of the modification of GO with polyethylenimine [43,44]. Fig.…”

“…When the carrier gases were changed back to N 2 at 75 C, the mass of PEI-GO decreased. Because temperature and pressure affect the equilibrium adsorption capacity [44], and the amine groups doesn't react the acid-base reaction with N 2 gases. A pair of amino groups interacts with a single CO 2 molecule at the carbon surface.…”

Carbon Dioxide Absorption by Polyethylenimine-Functionalized Nanocarbons: A Kinetic Study

“…In our previous work, 12 we established that the curvature of the nanocarbon substrate has an immediate effect on the rate of absorption of CO 2 with increased rates for higher curvatures. The present work supports this observation confirming that PEI-SWNT (high curvature) is faster than PEI-GO in absorbing CO 2 .…”

Pentaethylenehexamine-C60 for Temperature Consistent Carbon Capture

“…Within this research effort, our group has focused its attention on the development of new materials made from the immobilization of amine compounds on different types of carbon nanomaterials. Building upon the work of Barron et al, on the covalent functionalisation of nanocarbons with amines [12,13], we have developed fullerene-cross-linked polyethyleneimine (PEI)-based sorbents and characterized their CO2 capture performance [14][15][16][17][18]. In particular, PEI-C60 achieved very high CO2 capture selectivity and a maximum sorption capacity of 200 mg/g (mg CO2/g sorbent) [14].…”