Development of a low temperature adsorbent from karanja seed cake for CO sub(2) capture

The applicability of karanja (Pongamia pinnata) seed cake as a low temperature CO sub(2) adsorbent was examined. The processing of the cake was done by extraction and hydrothermal treatments, followed by calcination. The physico-chemical characteristics of sorbent materials were determined by nitrogen adsorption, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy-electron diffraction X-ray analysis (SEM-EDXA) and C super(13) solid state nuclear magnetic resonance (C super(13)-NMR) spectroscopy techniques. CO sub(2) uptake capacities of the sorbents were obtained by generating their breakthrough curves, in a fixed bed reactor connected to an on-line gas chromatograph. Hydrothermal treatment improved the surface area and afforded exposure of more sites for CO sub(2) adsorption. The hydrothermally treated cake showed higher adsorption capacity, easy thermal desorption and also good recyclability up to five consecutive cycles, as compared to its extracted analogue, proving it to be a promising adsorbent. The Yoon-Nelson rate constant values also supported the superior adsorption capacity of hydrothermally treated sample.