Carbon Dioxide Capture Using Functionalized Multi-Wall Carbon Nanotubes by Oxygen Rich Groups

Greenhouse gas (GHG) emissions and synthesis are a worldwide concern because they contribute to climate change and global warming. This work describes the attachment of oxygen-rich surface functional groups to MWCNTs through ultrasonication with a mixture of H2SO4/HNO3 and studying Adsorption behavior, temperature effects, isotherm analysis, and mechanism study. The MWCNTs surface had a few defects, according to the SEM study. After attachment of oxygen functional groups through ultrasonication, the surface roughness of MWCNTs was observed. Results of BET indicated decrease surface area and pore volume after functionalization Because of the presence of transport pores and the pore filling by acid molecules, the mass transfer properties were efficient. Using a volumetric method, the CO2 adsorption capacity was determined between 309 and 333 °K and pressures as high as 7 bar. The functionalization has made enhancement in CO2 capture capacity from 0.3428 to 0.5235 mmole/g. The breakthrough curves study variable flow rates (0.5, 1 and 1.5 l/m) and bed weights (1, 1.5, 2 g). Isotherms analysis shaw that the CO2 uptake decrease with temperature rises. Surface functionality groups and morphology of MWCNTs and Physical properties were analyzed by X-ray diffraction (XRD), Fourier Transforms Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), surface area Brunauer Emmett and Teller (BET). The results of the study showed that the creation of carbon dioxide-adsorption sites on multi-walled CNTs during the functionalization process is caused by functional groups connected to carbon nanotubes surfaces, which raises the adsorption capacity of MWCNTs.