A Nanoprotein-Functionalized Hierarchical Composite Air Filter

Abstract

Building nanostructured active materials and rational porous structures in air filters will be significant in realizing high filtration efficiency and low normalized pressure drop. The construction of nanofabrics by electrospinning can lead to large active surface areas, but it has been challenging to control the porous structures to reduce the normalized pressure drop, in particular for thick fabrics. To address this issue, here, we report a protein-functionalized composite air filter with hierarchical structures. This composite is made of bacterial nanocellulose coated by protein nanoparticles and microcellulose fibers from wood pulp. The protein-functionalized nanocellulose can not only help expose the functional groups of protein for trapping pollutants but also act as a binder to reinforce the composite fabrics. At the same time, the long microcellulose fibers form large pores, reducing normalized pressure drop and improving mechanical properties. By adjusting the component ratios, we demonstrate a high-performance protein/nanocellulose/microcellulose composite air filter with high filtration efficiency of above 99.5% for PM 1−2.5 but extremely low normalized pressure drop of 0.194 kPa/g, which is only about 1% of that for protein nanofabrics constructed by electrospinning. This study brings about a cost-effective strategy based on protein-functionalized hierarchical composite fabrics for fabrication of an advanced, green, sustainable air filter.

Review on Polymeric, Inorganic, and Composite Materials for Air Filters: From Processing to Properties

“…[130] Flexible, fibrous composite fibers were successfully prepared by simple drying of denatured protein with nano-and microcellulose suspensions on a thermal platform. [131] Recently, an antipathogen nanostructured silica matrix doped with silver nanocluster was coated on glass fiber-based air filters by means of a radio frequency cosputtering process, utilizing two cathodes made from silver and silica. [132] Prefabricated, noncontinuous, ceramic short fibers can be shaped into fibrous air filters by different techniques.…”

“…Mechanical properties should be considered, especially for nonstationary air filters, where vibration, shocks, and deformation could potentially lead to defects in the filter and, thus, decreased filter performance. Although there exist numerous flexible air filter materials, [28,29,[81][82][83]105,124,131,167,188] their highly porous structure makes air filters mechanically less robust than their dense counterparts. Therefore, they are usually deployed on mechanically more robust substrates or reinforced with rigid structures.…”

Low cost centrifugal melt spinning for distributed manufacturing of non-woven media

“…We evaluated the FEs and PDs of the processed materials using a setup similar to that used in previous studies on filtration materials ( S2 Fig ) [ 71 ]. FE measurements were made using incense smoke as a source of particles with a range from 0.01 to 5.0 μ m with a flow rate of 2.8 L / min .…”

Cellulose for the Production of Air-Filtering Systems: A Critical Review

“…This hierarchical structure showed the morphological features needed to well preserve a good balance between the filtration efficiency of above 99.5% for PM 1−2.5 and the low value of pressure drop of 0.194 kPa/g. The functionalized nanocellulose showed nanoprotrusion, which facilitates the aerosol particle capture, maintaining a reduced air flow resistance due to the large pores formed by the long nanofibers [86].…”