Fog Spraying Deposition of Wood Cellulose Nanofibers Containing Tert-Butanol on Tissue Paper for Air Filtration

This study investigated the use of fog-spraying deposition of wood cellulose nanofiber (WCNFs) suspensions on tissue paper (TP) to create air filter media. High-purity WCNFs, confirmed using ATR-FTIR spectroscopy, were found to be composed of cellulose I_β structures via x-ray diffraction with a crystallinity of 67%. The measured zeta potential of the aqueous suspension of WCNFs was −13 ± 1 mV, indicating the absence of acid hydration during their isolation. This study used nine grammage levels of sprayed WCNFs (ranging from 0.3 to 10 g/m²) and investigated the influence of tert-butanol (TB) on the performance of the medium. After coating, the specimens were freeze-dried and imaged using FE-SEM to confirm the proper distribution of WCNFs on the TP substrate. The key findings revealed that increasing the grammage level from 0.3 to 2 g/m² led to increased particulate matter (PM) adsorption and a significant pressure drop. However, increasing the grammage level from 2 to 10 g/m² decreased the adsorption efficiency, particularly for PM size of 0.3 µm (PM_0.3). The study concluded that the specimens prepared with a deposition of 2 g/m² grammage level of WCNFs containing TB were the optimal treatment, demonstrating an adsorption efficiency of 94.1% for PM_0.3 and a pressure drop of 123 Pa, compared to the corresponding values for bare TP, which were only 9.1% and 18 Pa, respectively.