Synthesis of CH3I-quaternized polypropylene nonwoven fiber grafted with imidazole (PP-g-Vim) to adsorb vapor phase ammonia.

Ammonia in gas phase has an unpleasant smell and is hazardous to human health. Though activated carbon has been widely used as a representative adsorbent, it is significantly vulnerable to humidity. In the study, a nonwoven fibrous polypropylene polymer was synthesized using a photo-graft reaction with imidazole followed by quaternization with CH3I. The time of each reaction was optimized for the maximum adsorption. The FT-IR confirmed that 1-vinyl imidazole (Vim) and methyl group (-CH3) were successfully introduced into PP fibers. The Langmuir isotherm characterized that the adsorption capacity was 44.84 mg NO3-N g-1. The adsorption intensity, 1/n, by Freundlich adsorption isotherm was 0.41 indicating that the adsorption of NO3-N onto PP-g-Vim-CH3I was favorable at the studied conditions. In the gas phase, maximum adsorption of was calculated to be 40 ±â€¯0.69 mg NH3 g-1 by BET model. Though the adsorption amount decreased by 2.5 times as the temperature increased from 15 °C to 45 °C, the amounts and rates of adsorption were not influenced by humidity. In conclusion, the synthesized PP-g-Vim-CH3I was able to ammonia in the gas phase at a range of humidity.