Water-resistant cellulosic filter for aerosol entrapment and water purification, Part I: production of water-resistant cellulosic filter.

Synthetic filters are neither biodegradable nor produced from renewable sources. Thus, their disposal has serious environmental impacts. There is a growing desire to produce filters from cellulosic fibers that are renewable, biodegradable, cheap and most importantly recyclable if the contamination is removed. Foam-laid process in papermaking is a promising process for the production of specialty papers. Filters produced using this process are capable of providing products with high specific surface area and tortuous structure favorable for entrapping particulate matters, while providing excellent permeability for incoming gas or liquid. Although the end product fulfills completely the requirement of a filter in a dry environment, it fails completely if it is exposed to a moist environment. This work reports on converting the hydrophilic cellulosic filter into a hydrophobic product without disturbing its original structure.