ساخت و ارزیابی خواص لایه جاذب فیلتر تنفسی با استفاده از نانوفیبر سلولز چوب.

Background and Objectives: Fine dust air pollution poses a significant health threat in arid and semi-arid regions worldwide. Inhaling these particles is linked to cardiovascular issues, reduced lung function, skin problems, respiratory irritation, and an increased risk of cancer. Existing respiratory masks often struggle to capture these fine particles (less than 2.5 microns) due to the limitations of conventional filter materials. This study explored enhancing respiratory filter performance by applying a deep-coating method with cellulose nanofibers (CNFs) on a cellulosic substrate. We investigated CNF concentrations of 0.05%, 0.1%, 0.2%, and 0.5%. Coated filters were freeze-dried at -50 °C and 0.04 mbar pressure. These modifications aimed to improve filter absorption capacity, addressing the limitations of conventional filters and offering a novel approach to mitigate health risks from fine dust inhalation. Materials and Methods: Wood cellulose nanofiber gel (WCNFs) was obtained from Nano Novin Polymer Co., Iran. Carboxymethyl cellulose (CMC) and citric acid (CA) were purchased from Dr. Mojallali Co., Iran. The cotton fabric substrate came from Live Co., Iran. Sample characterization employed Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), filter pressure drop measurement, field-emission scanning electron microscopy (FESEM), and a fine particle adsorption test. Results: The FTIR test confirmed the purity of the cellulosic substrate used for CNF coating. XRD analysis revealed the presence of β1-cellulose in the substrate, indicated by distinct peaks at 2θ angles of 15.5°, 16.5°, 22.5°, and 34.5°. This structure facilitated strong bonding between CNFs and the substrate. FESEM imaging confirmed the presence of nanofibers (below 100 nm), enabling the formation of nano- and submicron pores. While increasing CNF concentration generally raised pressure drop, the optimal treatment involved a 5-layer sample with two layers containing 0.5% CNFs. This configuration achieved a remarkable 96.18% absorption efficiency for particles smaller than 2 microns, exceeding the N95 standard set by the Food and Drug Administration. [ABSTRACT FROM AUTHOR]