Rates of Adsorption on Hydrotalcite Pellets with Respect to Modifications of Area for Removal of CO2

Abstract

Hydrotalcite (HTC) has recently attracted the attention of researches in CO2 removal technology because of its ability to adsorb appreciable amounts of CO2 compared with many other adsorbents. It is known that pelletized forms of HTC could meet commercial applications which can be easily handled, transported and are of market appeal. The objective of this research is to study the rates of adsorption of CO2 which is an important aspect in the determination of the viability of the removal of CO2 with respect to the modifications of HTC’s surface area that have been encountered. Some modifications of HTC morphology and surface structures with adsorption of CO2 was observed based on Scanning Electron Microscopy, Thermal Gravimetric Analyzer, X-Ray Diffraction Analyzer and analysis of adsorption area of HTC towards CO2. The modifications of area could be contributed by the disintegration and/or agglomeration effects. A model based on the Langmuir rate model was developed in order to investigate the interesting behavior of HTC area towards the adsorption of CO2. Based on a cross sectional area of a mole of CO2, which is 136.4 m2/mmol as reported by Aylmore et al. [31], the monolayer areas of HTC after adsorption of CO2 is calculated to be 177.32 m2/g. This value when being compared with the Brunauer Emmett and Teller (BET) value of commercial HTC which is 110.98 m2/g, it was found that there is an increase in equivalent areas of HTC after the adsorption of CO2.