Amidoxime-functionalized nanocrystalline cellulose-mesoporous silica composites for carbon dioxide sorption at ambient and elevated temperatures

A series of nanocrystalline cellulose (NCC)-mesoporous silica composites (NCC-AO) with attached double-amidoxime groups is synthesized and examined for CO2 sorption at both ambient (25 degrees C) and elevated temperatures (120 degrees C). NCC-AO composites showed high CO2 uptakes at ambient pressure, namely, 3.30 mmol g(-1) at 25 degrees C and 5.54 mmol g(-1) at 120 degrees C. The CO2 sorption capacity of NCC-AO at 1 atm and 120 degrees C is very high and exceeds the values reported so far for other sorbents under the same conditions. NCC-AO sorbents exhibited very good recyclability and were stable after ten successive adsorption/desorption cycles with negligible losses of the sorption capacity. Due to the high sorption capacity, reusability, thermal stability, relatively low cost and simple synthesis route, the NCC-AO composites show good potential as effective sorbents and catalysts, including CO2 sorption at elevated temperatures.