Retaining Surface Fibrillation of Wet-Beaten Wood Pulp in the Dry State

"Air filters produced from surface-fibrillated wood pulp may be a promising new, environmentally friendly means of removing pathogens from air. Such filters combine the attributes of large surface area with large permeability, are produced from a renewable resource, and are disposable by incineration as a carbon-neutral fuel when contaminated. We explored various approaches to producing high-surface fibrillated wood pulp fibers in the dry state and then forming them into high-performance filter pads. Wet beating of the bleached chemical pulp, followed by wet forming and partial freeze-drying to 85% consistency, then air-drying was the best approach. The resulting pads possessed large surface area and produced low pressure drop suitable for high-performance filtering of nano-size particles suspended in air."