CO
2 absorption by liquid-containing amines to form carbamate and bicarbonates is an effective method of CO
2 mitigation from industrial exhausts, but this process is expensive and requires large quantities of amines. Here we modified chitosan, a naturally occurring biopolymer containing NH
2 functions, to use it for CO
2 absorption in aqueous media. Chitosan was dispersed in 40% aqueous NaOH solution then treated with monochloroacetic acid dissolved in isopropanol, to yield
O-carboxymethylchitosan. Results show that the CO
2 absorption capacity of
O-carboxymethylchitosan is 0.508 g/g, which is higher than the capacity of conventional amines such as 1-aminoamine, 2-methylpropanolamine and methyldiethanol amine, but lower than the capacity of monoethanolamine. A cyclic study showed that
O-carboxymethylchitosan is a stable component for CO
2 absorption and regeneration.
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