Filtration performance of air filter paper containing kapok fibers against oil aerosols

High content of oil aerosols exist in the ambient air. In this study, the kapok fiber was studied for removing oil aerosols due to its oleophilic property and large lumen. The influence of the kapok fiber on filtration performance of air filter papers against the di-(2-ethyl hexyl) sebacate (DEHS) oil aerosols was analyzed. Firstly, different contents of kapok fibers were blended with hardwood fibers to make filter papers by the wet-laid process. Then the effects of the kapok fiber content on the morphology, thickness, air permeability, strength tensile and DEHS penetration of filter papers were studied. Finally, the DEHS loading performance of filter papers with different content of kapok fibers was evaluated. The results showed that as the content of the kapok fibers increased, the thickness and air permeability increased. The most penetrating particle size was 200 nm of all the papers and the filtration efficiency decreased as the content of kapok fibers increased. During the loading process, the pressure drop increased slowly in the first stage due to the deposition of the oil aerosols on the surface of the filter papers leading to the rise of the friction area. Then the pressure drop increased faster due to the rearrangement of oil aerosols in the filter papers. Finally, it increased exponentially since the oil aerosols formed bridges and films between the fibers and clogged the papers. It was found that as the content of kapok fibers increased, the loading time of the first and second stages became longer, which meant that the kapok fibers could improve the oil aerosols holding capacity. This study demonstrated the potential of using kapok fibers in air filter for removing oil aerosols.