Biochar (BC) obtained from durian shell carbonization was mixed with silicium-calcium slag particles as adsorbent carrier material. The mixture of BC and silicium-calcium slag particles was impregnated with pentaethylenehexamine (PEHA) liquid and then mixed with wet flue gas desulfurized gypsum (FGDG) slags to prepare wet amine functionalized CO2 solid adsorbents
which significantly improved adsorption activity than FGDG-free adsorbents. The adsorbents were characterized by FT-IR
TGA
SEM and N2 adsorption-desorption. Effect of FGDG slag content
adsorption temperature and CO2 concentration in flue gas on adsorption performance were studied in a fixed bed reactor. The results showed that moisture presence in FGDG slags changed reaction mechanisms between amino groups and CO2. Adsorbent with 30% FGDG had a maximum adsorption capacity of 2.33 mmol/g at temperature of 85℃ and its adsorption capacity decreased slightly by only 4.2% after 12 cycles of regeneration and reuse
showing a favorable adsorption stability. The isosteric heat of CO2 adsorption calculated with Clausius-Clapeyron equation was found between heats of physical and chemical adsorption
suggesting simultaneous occurrence of physical and chemical interactions in adsorption process. Fitting experimental data with kinetic models showed that pseudo-first-order and pseudo-second-order models did not fit accurately but Avrami model fitted well
which further indicated that CO2 adsorption process on BC/SCS-PEHA-30%FGDG is not a simple physical or chemical adsorption process
but a combination of these two adsorption processes.