MgO/CaO-loaded porous carbons for carbon dioxide capture

Abstract

Nanoporous carbons loaded with both MgO and CaO were prepared by a simple heating of mixtures consisting of poly(ethylene terephthalate) and natural dolomite. Preparations were carried out at temperatures ranging from 850 to 1,000 °C that ensured complete thermal decomposition of the dolomite contained in the mixtures to the oxides. An influence of the PET/dolomite weight ratio and temperature of the preparation process on the porosity of the obtained composite products and on CaO and MgO crystallite sizes are discussed using the results of nitrogen adsorption/desorption at 77 K and X-ray diffraction analyses, respectively. Performances of the hybrid materials as sorbents for carbon dioxide were examined using thermogravimetric analyses. Finally, possibility of regeneration of the spent sorbent materials together with a side—effect accompanying this process are discussed on the basis of thermogravimetric measurements. As found, a part of CO2 captured by the hybrid sorbents gets adsorbed weakly and another portion is fixed strongly. During thermal regeneration, the strongly fixed CO2 reacts with carbon material. In this way small fraction of a sorbent is lost.