CO2 adsorption by coal fly ash zeolite and modified zeolite-templated carbon

Abstract

Coal fly ash (CFA), as the main by-product of coal-fired power plants, has a high content of silica-aluminium elements that can be used to prepare zeolite by the alkali fusion method with sound CO2 adsorption capacity. Among the four effect factors of Si/Al, NaOH/CFA, H2O/AFP(alkali fusion product), and crystallisation time, NaOH/CFA had the greatest effect on the CO2 adsorption performance of coal fly ash zeolite (CFAZ), followed by Si/Al and H2O/AFP, and crystallisation time had the least effect. The CO2 adsorption performance of the samples was tested and analysed using the thermal analysis method, the CO2 adsorption amount of CFAZ reached 4.23 mmol g–1 (30 °C, 101 kPa). In addition, the CFAZ and the zeolite-templated carbon (ZTC) adsorption performance is poor at high temperatures. The co-precipitation method modification of CFAZ and ZTC can produce layered double hydroxide derived material, which can adsorb CO2 at high temperatures reached at 3.35 mmol/g (650 °C, 101 kPa). Moreover, ZTC modified with polydivinylbenzene as the hydrophobic material has a sound CO2 adsorption effect in high-humidity environments. Thus, different adsorbents also could be produced using CFA to capture CO2 with a wide temperature range between 25 and 650 °C.