High performance CO2 capture at elevated temperatures by using cenospheres prepared from solid waste, fly ash

Cenospheres (CS) are spherical shaped inorganic frameworks present in with fly ash which is generated from coal-fired thermal power plants. These spherical structures were functionalized with imidazole and amine moieties to capture CO2 selectively from flue gases at elevated temperature. The functionalized CS have shown a high selectivity for CO2 adsorption (4.68 mmol g-1) over N2 (0.46 mmol g-1) at 333 K/1 bar from a simulated flue gas (0.15 CO2 and 0.85 N2, v%) composition of thermal power plants. When the moisture content reached to 30 vol% the adsorption capacity of CS materials was reduced to 20 vol% as compared to dry flue gas. The functionalized CS can be used repeatedly for 50 cycles without losing its adsorption capacity. The cost estimate for CO2 capture by using the proposed adsorption system would be $12.01/ton of CO2 which is lower as compared to amine absorption system and zeolite-based adsorption system reported in the literature. The CS materials are prepared from solid wastes reduce the cost of production and their large scale manufacturing is technically feasible to capture CO2 from industrial flue gases efficiently in near future.

Automated summary

Cenospheres functionalized with imidazole and amine moieties have been found to have high selectivity for CO2 adsorption over N2 in simulated flue gas conditions. Despite a reduction in adsorption capacity with increased moisture content, the functionalized CS can be used repeatedly without loss of effectiveness. The estimated cost for CO2 capture using this system is lower than other existing absorption systems, making large scale manufacturing of CS materials a potential cost-effective solution for efficient CO2 capture from industrial flue gases.