Alongside lignin and hemicellulose, cellulose is one of the structural components of wood. In industrial processing, cellulose is extracted from wood chips by either boiling or partly mechanically, to be later used in papermaking.
Nanofibrillated cellulose, or NFC, is an organic biopolymer processed from cellulose. For a few years now, nanocellulose, which can be turned into a thick gel, has been investigated in Finland for the purposes of mine water purification.
The effect of nanocellulose is based, among other factors, on the fact that the chemical traits of the nanofibres can be altered according to the substance to be bound. In watery solutions, nanocellulose gels are able to simultaneously bind metal and sulphate ions, substances which mine water often contains. Ideally, the bound substances can then be released for industrial reuse.
Now, as a result of work carried out by Finnish researchers, patents have been granted for the utilisation of both positively and negatively charged nanocellulose, with research continuing at an even more intense pace.
“We are about to study in more detail the basis of the ability of nanofibrillated cellulose to bind various substances. Additionally, we are looking into the types of water responsive to nanocellulose treatment, as well as functional ways of releasing and recycling substances bound by nanocellulose. The first experiments were conducted on mine water originating in the mine operated by Terrafame in Sotkamo, northern Finland, but we are now interested in testing other kinds of water as well,” says Salla Venäläinen, one of the inventors and university lecturer at the Faculty of Agriculture and Forestry, University of Helsinki.
The other inventors are Helinä Hartikainen, professor emerita in soil and environmental chemistry at the University of Helsinki, and Markus Nuopponen and Anne Meriluoto from UPM-Kymmene. The NFC used in the research (UPM Biofibrils) is a product of UPM-Kymmene. The patents are held by UPM-Kymmene.
More on the subject:
Venäläinen, S.H. & Hartikainen, H. 2017. Retention of metal and sulphate ions from acidic mining water by anionic nanofibrillated cellulose. Science of the Total Environment 599–600: 1608–1613.
Venäläinen, S.H. & Hartikainen, H. 2017. Anionic nanofibrillated cellulose – A sustainable agent to recover highly soluble salts from industrial effluents. Environmental Technology & Innovation 8: 282—290.
Venäläinen, S.H. & Hartikainen, H.H. 2018. Resource-efficient purification of acidic multi-metal process water by means of anionic nanofibrillated cellulose. Journal of Cleaner Production 185: 561—522.