Synthesis of β-cyclodextrin grafted itaconic acid and its selective adsorption to ammonia in mainstream cigarette smoke

To develop adsorptive materials that can selectively reduce the release of ammonia in cigarette smoke, β-cyclodextrin grafted poly (itaconic acid) (β-CD-g-IA) was synthesized via copolymerization of β-cyclodextrin with itaconic acid by using ammonium peroxydisulfate as evocating agent. The obtained materials were characterized by means of FT-IR, ¹H NMR, SEM, N₂ adsorption-desorption and TG-DTG. β-CD-g-IA was added into cigarette filters to investigate its adsorption effect to ammonia in mainstream cigarette smoke. The results showed that:1) Under the optimized condition of IA/β-CD ratio 3:0.17 (mol/mol), reaction temperature 70℃, the amount of ammonium peroxydisulfate 3.0%, and reaction time 3 h, the grafting percent (GP) of IA was the highest and reached 38.0%. 2) The characterization results confirmed that IA was effectively grafted on β-CD, and β-CD-g-IA had typical mesoporous structure (pore size 20 nm, specific surface area 309 m²/g). 3). When β-CD-g-IA was added into cigarette filters at a rate of 20 mg/cig, the release of ammonia in mainstream cigarette smoke was reduced by 54.0%. The adsorption effect of β-CD-g-IA was much better than that of the raw material added alone or a mixture of the individual materials. The β-CD-g-IA only selectively absorbs the ammonia, it had no measurable adsorption to the other components in mainstream cigarette smoke.