A cellulose composite filter with multi-stage pores had high filtration efficiency, low pressure drop, and degradable properties

Abstract

The increasing air pollution has drawn attention to the importance of using protective masks. The non-biodegradable nature of conventional disposable masks can have a significant ecological impact. Cellulose materials have great potential in degradable filters. In this study, a three-layer cellulose pore structure was designed for an antimicrobial integrated cellulose filter (Int-CF&Z/C) based on the generalized Murray's law. Int-CF&Z/C was constructed using cellulose nanofibers to create cellulose filter layers with three different pore sizes. The three-layer pore-size gradient of Int-CF&Z/C not only enables Multiple filtration of particulate matter (PM) but also enhances dust capacity and reduces pressure drop. Then, the binary composite of ZIF-8 and CuO was added to the cellulose filter layer with the smallest pore size. This addition aims to improve the filtration performance, moisture resistance, and antimicrobial properties of the filter. The Int-CF&Z/C had a filtration efficiency of 97.7 % for non-oily PM0.3 and 98.5 % for oily PM0.3, with a pressure drop of only 74 Pa. Furthermore, the filtration performance of the filter exhibited a significantly lower decline compared to that of an N95 filter when utilized in prolonged periods in humid environments. Importantly, the filter could completely degrade in compost soil within approximately two months.