Modified fibrous silica for enhanced carbon dioxide adsorption: Role of metal oxides on physicochemical properties and adsorption performance

This work investigates the effectiveness of FS loaded with CaO, MgO, and CeO2 for CO2 adsorption. Different techniques such as XRD, ATR-FTIR, Raman, CO2-TPD, in situ FTIR, FESEM, and TEM were employed. Upon the metal oxides loading, the alteration of textural properties, increases in the weak and moderate basic strength and quantity of basic active sites as well as disappearance of the dendritic structures in CaO/FS were observed. The in situ FTIR studies confirmed the formation of different carbonates species upon the interaction with CO2. The greatest CO2 physisorption capacity was demonstrated by CaO-FS (0.76 mmol/g), while the highest CO 2 chemisorption uptake was shown by MgO-FS (9.77 mmol/g). The CO2 physisorption activity depends mainly on the porosity and basic strength of the adsorbents. On the contrary, the CO2 chemisorption performance is determined by the basic strength and basic sites as well as CO2 affinity of the adsorbents.

Automated summary

The study investigated the effectiveness of FS loaded with CaO, MgO, and CeO2 for CO2 adsorption, observing changes in textural properties and basic strength upon metal oxides loading. Different carbonate species were confirmed by in situ FTIR studies. CaO-FS showed the highest CO2 physisorption capacity, while MgO-FS exhibited the highest CO2 chemisorption uptake. The physisorption activity depends on porosity and basic strength, while chemisorption performance is determined by basic strength and CO2 affinity.