Processing of nanocellulose sheet for capturing fine particulate matter

Abstract

Nanofibers have gained more interest in recent times due to their high surface area. One such class of fibers being nanocellulose fibers are biodegradable and hydrophilic depending on the amount of lignin present. In this work, wood chips were subjected to Kraft cooking and the resulting pulp was refined using Lab Valley Beater (LVB) and Super masscolloider (SMC). Refining was carried out using three different parameters to obtain the high aspect ratio fibers. LVB refining yielded short-length, micron diameter fibers (<1000 µm) whereas SMC refining yielded longer length, smaller diameter fibers (<900 nm). The properties of the refined slurry were analyzed using consistency and Canadian standard freeness (CSF) tests to gauge the structure–property relationship, especially the drainability of sheets. Sheets consisting of micro and nanocellulose fibers were prepared using a Whatman filter of 10 µm pore size. LVB refining of 60 mins was sufficient to obtain sheets with optimum porosity, consistency, CSF, and tensile elongation. SMC sheet made from 0.01 clearance revealed high aspect ratio fibers, high tensile strength, low elongation, low CSF, low consistency, and low porosity. Therefore, this sheet was used to capture fine particulate matter (PM2.5) from the air at 25–500 µg/m3 concentration and was concluded as a possible alternative to Teflon sheets to capture fine dust (PM2.5).