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

Abstract

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.

Water-stable cellulose fiber foam with antimicrobial properties for bio based low-density materials

“…To the authors' knowledge, it is the first time citric acid and chitosan has been used to produce a water-stable low-density cellulose fiber foam material with antimicrobial properties, using sodium dodecyl sulfate (SDS) as a foam forming agent. This simple production process facilitates largescale production, as it does not include costly steps like freeze-drying or organic solvents, as many other processes do (Abraham et al 2017;Heydarifard et al 2016). The antimicrobial effect of the cellulose fiber foams towards both bacteria and fungi have been evaluated, as both bacteria and fungi play an important role in microbial degradation.…”

Foam forming of fiber products: a review

“…For thick materials with low density, compression behavior is often the most important strength characteristic. As suggested by Equations (15) and (16), the compression modulus and stress depend strongly on the density of the material together with the bending stiffness of the fibers and their bonding. This is shown in Figure 30, where the stiffer CTMP fibers lead to much higher compression stress than the flexible kraft fibers.…”

“…However, for both types of fibers, the stress increases with density as a power law with the power close to 2. This is explained by the increasing number of inter-fiber joints, as described by Equation (16).…”

“…Foam forming is a process that enables the making of a variety of fiber products, [1] ranging from paper [2][3][4][5][6] and lightweight packaging [7] to nonwoven fabrics [8][9][10] and insulation, [11][12][13][14][15] filtering [13,16,17] and construction materials. In this method, the advantages of traditional water-forming technology are combined with the improved ability of handling very different kinds of raw materials such as long fibers [10,18] or particles with varied densities.…”

Improving Compression Recovery of Foam-formed Fiber Materials

“…In simple terms, it combines the ability of water to act as a strong cellulose binder with the ability of bubbles to tailor a porous structure and prevent fiber flocking. Lately, the technology has been intensely studied in the preparation of sheet structures (Radvan and Gatward 1972;Lehmonen et al 2013) and bulk materials (Madani et al 2014;Alimadadi and Uesaka 2016) made from wood fibers, especially for filtering (Heydarifard et al 2016) and insulating applications (Poranen et al 2013;Pöhler et al 2016). Forming and subsequent water removal and drying methods have a profound effect on the sheet structure (Timofeev et al 2016;Haffner et al 2017).…”