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| Titel: |
ALGINATES DECOLORATION BY HYPOCHLORITE |
| Auteur: |
Ochoa, F. Sabatier, J. Ferrer, A. |
| Verschenen in: |
International journal of polymeric materials |
| Paginering: | Jaargang 51 (2002) nr. 8 pagina's 745-758 |
| Jaar: |
2002-08 |
| Inhoud: |
The isolation and purification of alginates from seaweeds -decoloring with hypochlorite- has been discussed by different authors, but a study about the influence of hypochlorite treatment on alginate properties was not found. The aim of this work has been the research of hypochlorite decoloration in order to obtain highly decolored alginates that have suffered minimal degradation during isolation. Preliminary experiments were carried out varying the hypochlorite dose from 1, 5 to 25,0 percentage on dry weight alga basis. Alginate yield was determined, while hypochlorite consumption and pH changes in time were measured. Infrared and UV-Visible spectra of alginates were recorded. Hypochlorite consumption was complete from the very beginning of the reaction for all experiments where an hypochlorite dose of 10% or less was applied, meanwhile low yields were obtained when the dosage was 15% or higher. Alginate absortivity (g -1 Lcm -1 ) in UV-Visible spectra decreases when hypochlorite dose increases, but no differences were found for doses of 15 and 25%, which cause a deep degradation as confirmed IR spectra. Hypochlorite dose (6 to 12%) and initial reaction pH (9, 5 to 10, 5) were varied in a 2 2 factorial design where an additional experiment was conducted at 9% hypochlorite and pH 10. Viscosimetric molecular weights were measured in addition to the responses determined for preliminary experiments. For those experiments at 12% hypochlorite the consumption was not complete, even at a reaction time of 45 minutes, but residual hypochlorite and pH reached stationery values at 30 minutes. This fact indicates that hypochlorite consumption must be monitored during decoloration and that this reaction must not exceed 30 minutes, when used the procedure here described. A dosage of 6% hypochlorite produces highly colored alginates, while 12% causes excessive degradation. Hypochlorite dose of 9% assures good decoloration and keeps, at the same time, degradation as controlled as possible. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 1 van 9 gevonden artikelen
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