Resource-efficient purification of acidic multi-metal process water by means of anionic nanofibrillated cellulose

Show full item record



Permalink

http://hdl.handle.net/10138/313478

Citation

Venäläinen , S H & Hartikainen , H 2018 , ' Resource-efficient purification of acidic multi-metal process water by means of anionic nanofibrillated cellulose ' , Journal of Cleaner Production , vol. 185 , pp. 516-522 . https://doi.org/10.1016/j.jclepro.2018.03.096

Title: Resource-efficient purification of acidic multi-metal process water by means of anionic nanofibrillated cellulose
Author: Venäläinen, Salla H.; Hartikainen, Helinä
Contributor: University of Helsinki, Department of Agricultural Sciences
University of Helsinki, Department of Agricultural Sciences
Date: 2018-06-01
Language: eng
Number of pages: 7
Belongs to series: Journal of Cleaner Production
ISSN: 0959-6526
URI: http://hdl.handle.net/10138/313478
Abstract: Treatment of acidic mining water (MW) with industrial minerals and alkaline chemicals requires utilisation of unrenewable raw materials and produces disposable inorganic sludges of no further use. We investigated the efficiency of bio-based anionic nanofibrillated cellulose (NFC) to purify authentic MW high in metals and sulphate. In a short-term (10 min) adsorption experiment, highly acidic (pH 3.2) multi-metal process water was treated with anionic NFC gels differing in their consistency (1.1%, 1.4% and 1.8% wow) at three sorbent-to-solution ratios. To unravel the purification efficiency of the NFC gels, MW was treated stepwise with a set of fresh NFC gels in three sequential batches. Each treated solution was filtrated before pH measurement and analysis for the NFC-induced changes in the metal and sulphate concentrations. All NFC gels efficiently co-adsorbed metals and sulphate and decreased the acidity of MW. Depending on the dosage, a triplicated treatment with the NFC gels removed as much as 32-75% of metal cations and 34-75% of sulphate anions. The retention of metals highly exceeded the amount of carboxyl groups in the sorbent Thus, we concluded that, instead of electrostatic adsorption, the retention took place through formation of covalent metal-NFC complexes. The subsequent surplus in positive total charge formed on the NFC-surface, in turn, enabled electrostatic co-adsorption of sulphate anions. The mutual interactions between cellulose nanofibrils in the NFC gel weakened with decreasing consistency, which promoted the accessibility of the sorption sites. This improved the purification efficiency while decreasing the demand for cellulosic raw material. We concluded that anionic NFC could potentially serve as a multifunctional and resource-efficient purification agent in the treatment of acidic process waters of high ionic strength. Ideally, the elements retained could be liberated and recycled elsewhere. (C) 2018 Elsevier Ltd. All rights reserved.
Subject: Water purification
Mining
Co-adsorption
Metals
Sulphate
WASTE PULP RESIDUES
AQUEOUS-SOLUTION
MINE DRAINAGE
HEAVY-METALS
IONS
ADSORPTION
NANOFIBERS
NANOCELLULOSE
NANOMATERIALS
REMEDIATION
1172 Environmental sciences
415 Other agricultural sciences
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
Venalainen_MANUSCRIPT_R2.pdf 699.6Kb PDF View/Open

This item appears in the following Collection(s)

Show full item record