title: Cationic cellulose nanofibers from waste pulp residues and their nitrate, fluoride, sulphate and phosphate adsorption properties.
abstract: Cationic cellulose nanofibers (CNF) having 3 different contents of positively charged quaternary ammonium groups have been prepared from waste pulp residues according to a water-based modification method involving first the etherification of the pulp with glycidyltrimethylammonium chloride followed by mechanical disintegration. The cationic nanofibers obtained were observed by scanning electron microscopy and the extent of the reaction was evaluated by conductometric titration, ζ-potential measurements, and thermogravimetric analyses. The cationic CNF had a maximum cationic charge content of 1.2mmolg(-1) and positive ζ-potential at various pH values. Sorption of negatively charged contaminants (fluoride, nitrate, phosphate and sulphate ions) and their selectivity onto cationic CNF have been evaluated. Maximum sorption of ∼0.6mmolg(-1) of these ions by CNF was achieved and selectivity adsorption studies showed that cationic CNF are more selective toward multivalent ions (PO4(3-) and SO4(2-)) than monovalent ions (F(-) and NO3(-)). In addition, we demonstrated that cationic CNF can be manufactured into permeable membranes capable of dynamic nitrate adsorption by utilizing a simple paper-making process.
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Applied Wood Materials Laboratory, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland. Electronic address: houssine.sehaqui@empa.ch.
authors.forename: Houssine
authors.initials: H
authors.lastname: Sehaqui
authors.affiliation: Polymer & Composite Engineering (PaCE) Group, Department of Chemical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom; Institute for Materials Chemistry & Research, University of Vienna, A-1090 Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mautner
authors.affiliation: Cemitec, Polígono Mocholí, Plaza Cein 4 31110 Noain, Navarra, Spain.
authors.forename: Uxua
authors.initials: U
authors.lastname: Perez de Larraya
authors.affiliation: Eawag, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland.
authors.forename: Numa
authors.initials: N
authors.lastname: Pfenninger
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Applied Wood Materials Laboratory, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Tingaut
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Applied Wood Materials Laboratory, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
authors.forename: Tanja
authors.initials: T
authors.lastname: Zimmermann
keywords: Adsorption; Cellulose nanofibers; Filtration; Fluoride; Nitrate