title: Porous thin film barrier layers from 2,3-dicarboxylic acid cellulose nanofibrils for membrane structures.
abstract: To fabricate a strong hydrophilic barrier layer for ultrafiltration (UF) membranes, 2,3-dicarboxylic acid cellulose nanofibrils with high anionic surface charge density (1.2 mekv/g at pH 7) and a width of 22 ± 4 nm were used. A simple vacuum filtration method combined with a solvent exchange procedure resulted in a porous layer with a thickness of ∼ 0.85 μm. The fabricated membranes reached high rejection efficiencies (74-80%) when aqueous dextrans up to 35-45 kDa were filtrated to evaluate the molecular weight cut-offs (MWCO). A linear correlation between the barrier layer thickness and the flux rate was observed in all tested cases. Further optimization of the barrier layer thickness can lead to an even more effective structure.
authors: Fibre and Particle Engineering Laboratory & Thule Institute, University of Oulu, PO Box 4300, FI-90014 Oulu, Finland. Electronic address: miikka.visanko@oulu.fi.
authors: Miikka
authors: M
authors: Visanko
authors: Fibre and Particle Engineering Laboratory, University of Oulu, PO Box 4300, FI-90014 Oulu, Finland. Electronic address: Henrikki.Liimatainen@oulu.fi.
authors: Henrikki
authors: H
authors: Liimatainen
authors: Department of Chemistry, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland. Electronic address: Juho.Sirvio@oulu.fi.
authors: Juho Antti
authors: JA
authors: Sirviö
authors: Fibre and Particle Engineering Laboratory, University of Oulu, PO Box 4300, FI-90014 Oulu, Finland. Electronic address: Antti.Haapala@oulu.fi.
authors: Antti
authors: A
authors: Haapala
authors: Optoelectronics and Measurement Techniques Laboratory, University of Oulu, PO Box 4500, FI-90014 Oulu, Finland. Electronic address: Rafal@ee.oulu.fi.
authors: Rafal
authors: R
authors: Sliz
authors: Fibre and Particle Engineering Laboratory, University of Oulu, PO Box 4300, FI-90014 Oulu, Finland. Electronic address: Jouko.Niinimaki@oulu.fi.
authors: Jouko
authors: J
authors: Niinimäki
authors: Department of Chemistry, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland. Electronic address: Osmo.Hormi@oulu.fi.
authors: Osmo
authors: O
authors: Hormi
keywords: Barrier layer; Cellulose nanofibrils; Chlorite oxidation; Periodate oxidation; Rejection percentage; Ultrafiltration