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- Metsämuuronen, Sari, et al.
(författare)
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Natural organic matter removal from drinking water by membrane technology
- 2014
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Ingår i: Separation and Purification Reviews. - : Informa UK Limited. - 1542-2119 .- 1542-2127. ; 43:1, s. 1-61
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Tidskriftsartikel (refereegranskat)abstract
- Aquatic natural organic matter (NOM) is a heterogeneous mixture of biopolymers and their degradation products that cause harmful by-products during drinking water production. The great variability in NOM composition makes it difficult to completely remove from drinking water by any single technique. The current paper reviews the NOM removal by micro-, ultra- and nanofiltration and by hybrid processes combining membrane techniques with other unit processes: coagulation, adsorption, and oxidation, and by membrane bioreactors.
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| 2. |
- Niemi, Harri, et al.
(författare)
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Evaluation of degradation tendency of wood polymeric compounds in wood extract at high temperature
- 2015
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Ingår i: 18th International Symposium on Wood, Fiber and Pulping Chemistry, September 9-11, 2015, Vienna. ; , s. 382-384
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study aims to find out the effect of exposure time and process conditions on changes of the wood extract from hot water extraction, when it is exposed at high temperature after the extraction. This information is needed, when an intensified process combining extraction and separation is designed for recovery of hemicelluloses, because in a process of this kind theextract is exposed to high temperature also after the extraction step.The study was done with two different extract batches. The extract 1 was produced at 140 oC (circulation time 2 hours) and the extract 2 at 160 oC (circulation time 1.5 hours). Samples of these extracts were exposed to 120 oC and 160 oC for different timeperiods between 15 and 285 minutes (0.25-4.75 hours).Based on this study it seems that processing of the extract at high temperature would likely to be safe at 120 oC for several hours, while at 160 oC no longer than 2-3 hours processing times can be recommended. The 4 hours exposure to 120 oC caused a clear decrease (20-30%) only in lignin amount (based on UV absorbance) but hemicellulose, monosaccharide and solid concentrations were not significantly affected. The five hours exposure to 160 oC caused remarkable hemicellulose losses (%). In addition, significant changes could be observed in lignin and solids content of the extracts.
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