Enhanced dual-gas adsorption of ammonia and acetaldehyde via Cu-BTC/ZIF-8 MOF-on-MOF structures grown on cellulose acetate nanofibers.

The simultaneous removal of ammonia (NH3) and acetaldehyde (C2H4O), two hazardous volatile organic compounds, is essential for air quality improvement. In this study, cellulose acetate (CA) nanofibers were functionalized with the MOF-on-MOF type of Cu3(1,3,5-benzentricarboxylate)2 and zeolite imidazolate framework (ZIF)-8 metal-organic frameworks (MOFs) to enhance their dual-gas adsorption performance. Under single-gas conditions, the porous CA-based MOF-on-MOF type of Cu-BTC/ZIF-8 nanofibers (CACu/ZIF) achieved adsorption capacities of 77.4 × 10-2 mmol/g for NH3 and 3.25 × 10-2 mmol/g for C2H4O. Remarkably, under mixed-gas conditions, the adsorption capacities increased to 82.8 × 10-2 mmol/g for NH3 and 7.83 × 10-2 mmol/g for C2H4O, demonstrating a significant enhancement in acetaldehyde adsorption. This improvement was attributed to the synergistic interactions between NH3 and C2H4O, with NH3 facilitating the formation of C-N bonds with acetaldehyde, thereby promoting additional adsorption. The hierarchical porous structure of CACu/ZIF provided abundant active sites for maximizing adsorption efficiency. These results indicate that MOF-functionalized nanofibers can effectively capture multiple pollutants, making them promising candidates for advanced air purification applications. This study highlights the importance of mixed-gas interactions in adsorption processes and provides valuable insights into the optimization of nanofibers for air purification.