Building a Tailored\nFrame-Channel Structure for High-Performance\nProtein Air Filters

To create a healthier indoor environment via sustainable\ntechnologies,\nthere is a growing demand for constructing high-performance air filters\nfrom natural materials. Addressing this need, we have fabricated high-performance\nprotein air filters with a tailored frame-channel structure via electrospinning.\nThe innovative feature of the protein air filter is generated by adding\na small amount of an organic salt, tetrabutylammonium chloride (TBAC),\nto modulate the denaturation of zein for tuning electrical charge\ndistribution and hydrophilicity of the protein solutions. The results\nhighlight that the optimized filter with 1.0 wt% TBAC exhibits a denser\nnanofiber assembly on the frame and a sparser arrangement on the channel.\nFunctionally, the filter demonstrates ultralow pressure drop (ca.\n9.04 Pa) that is only a third of that observed in unmodified formulation\nand commercial air filters, while it maintains high filtration efficiency\nin capturing PM<sub>2.5</sub> (99.42% ± 0.30%) and PM<sub>0.3</sub> (98.25 ± 0.39%). More importantly, the filter indicates multifunctional\nperspectives, e.g., high removal efficiency for formaldehyde (HCHO)\nand PM<sub>2.5</sub> under high airflow rates (up to 8 L/min) or after\nprolonged testing period (120 min). Our design of the frame-channel\nstructure for the protein air filter marks a leap forward in developing\nbiomass-based structural materials.