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

ABSTRACT 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/m 2 ) 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/m 2 led to increased particulate matter (PM) adsorption and a significant pressure drop. However, increasing the grammage level from 2 to 10 g/m 2 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/m 2 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.