title: Nanoporous membranes with cellulose nanocrystals as functional entity in chitosan: removal of dyes from water.
abstract: Fully biobased composite membranes for water purification were fabricated with cellulose nanocrystals (CNCs) as functional entities in chitosan matrix via freeze-drying process followed by compacting. The chitosan (10 wt%) bound the CNCs in a stable and nanoporous membrane structure with thickness of 250-270 μm, which was further stabilized by cross-linking with gluteraldehyde vapors. Scanning electron microscopy (SEM) studies revealed well-individualized CNCs embedded in a matrix of chitosan. Brunauer, Emmett and Teller (BET) measurements showed that the membranes were nanoporous with pores in the range of 13-10nm. In spite of the low water flux (64 Lm(-2) h(-1)), the membranes successfully removed 98%, 84% and 70% respectively of positively charged dyes like Victoria Blue 2B, Methyl Violet 2B and Rhodamine 6G, after a contact time of 24h. The removal of dyes was expected to be driven by the electrostatic attraction between negatively charged CNCs and the positively charged dyes.
authors.affiliation: Division of Materials Science, Luleå University of Technology, 97187, Luleå, Sweden; Department of Civil, Environmental and Natural Resources Engineering, Division of Sustainable Process Engineering, 97187, Luleå, Sweden.
authors.forename: Zoheb
authors.initials: Z
authors.lastname: Karim
authors.affiliation: Division of Materials Science, Luleå University of Technology, 97187, Luleå, Sweden. Electronic address: aji.mathew@ltu.se.
authors.forename: Aji P
authors.initials: AP
authors.lastname: Mathew
authors.affiliation: Department of Civil, Environmental and Natural Resources Engineering, Division of Sustainable Process Engineering, 97187, Luleå, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Grahn
authors.affiliation: Department of Civil, Environmental and Natural Resources Engineering, Division of Sustainable Process Engineering, 97187, Luleå, Sweden.
authors.forename: Johanne
authors.initials: J
authors.lastname: Mouzon
authors.affiliation: Division of Materials Science, Luleå University of Technology, 97187, Luleå, Sweden.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Oksman
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D004396:Coloring Agents / Q000302:isolation & purification*; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D016062:Porosity; D014462:Ultrafiltration / Q000295:instrumentation / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000295:instrumentation / Q000379:methods
chemical_list: D004396:Coloring Agents; D008567:Membranes, Artificial; D014874:Water Pollutants, Chemical; D002482:Cellulose; D048271:Chitosan
keywords: Adsorption; Cellulose nanocrystals; Chitosan; Dye removal; Nanoenabled membranes; Water purification