CO2 History of engineering & technology 8 Technology: general issues 7 Research & information: general 5 adsorption 4 carbon dioxide 4 climate change 4 optimization 4 response surface methodology 4 CO2 emissions 3 biochar 3 biomass 3 carbonation 3 composite 3 energy consumption 3 energy efficiency 3 energy storage 3 modeling 3 nanofluids 3 photocatalysis 3 thermal energy storage 3 Al2O3 2 Biology, life sciences 2 CH4 2 CO2 sequestration 2 COVID-19 2 EOR 2 HVAC 2 IAQ 2 NSGA-II 2