Characterization of Mixed Amine Functionalized Carbon Nanotube from Nigerian Sub Bituminous Coal

Abstract

It is a known fact that the behaviour and performance of any sorbent material such as functionalized CNTs is dependent on its inherent or modified micro structural property. Carbon nanotubes (CNTs) adsorbent was produced and characterized from Nigerian Sub-bituminous coal obtained in Udi, Enugu state. This is to determine the suitability of the mixed amine functionalized CNT adsorbent for CO2 adsorption, inorder to help in the mitigation of global warming. A mixture of two amines (Mono ethanol Amine (MEA) and Tri ethanol amine (TEA)) of different proportion was immobilized into the pores of the Carbon nanotube by wet impregnation method. The prepared adsorbent was characterized before and after amine modification with X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), Transition Electron Microspore (TEM) Scanned Electron Microscope (SEM), and thermogravimetric analysis (TGA) technique. Results from the XRD analysis shows that there is a drastic decrease in the height of the peaks at 2θ = 27, which correspond to 100 for CNT-MEA x-TEA y composites. This can be attributed to the filling of the pores by the amine in the Carbon nanotube. Similarly, there is a dominating appearance of amine functional group at different peaks of the FTIR spectrum.  Furthermore, the internal morphology of the adsorbent as revealed by the TEM image shows that the dominant product is a twisted multi-walled CNT, which is partly filled with metal-like particles from the catalyst. The SEM image depicts a clear variation in the surface chemistry of the various CNTs initiated by differences in the mixed amine formulation. Finally, observation from the BET analysis shows a decrease in the surface area, total pore volume and pore size of the CNTs adsorbent after it was modified with Amine. All of these result shows that combination of the two different amines, can further improve the adsorption capacity of functionalized CNT sorbents for CO2 adsorption, in mitigating global warming.