Dye adsorption studies on chitin and chitosan

Mazengarb, S.A., 2002. Dye adsorption studies on chitin and chitosan. MPhil, Nottingham Trent University.

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This thesis reports on the mechanism of adsorption of metallised and non-metallised dyes by chitin and chitosan at neutral pH. This was achieved by examining the build up of various pre-metallised and non-metallised acid and direct dyes on powdered chitin and the diffusion characteristics of these dyes through chitosan films. The effects of varying temperature and electrolyte concentration were also examined to assess any effects these may have on the adsorption characteristics of chitin and chitosan. The stability of the dye-fibre interaction was examined using Soxhlet extractions and colour-fastness tests developed for textile quality assessment. Comparison has been made between the adsorption mechanisms of cellulose, wool and nylon under normal dyeing conditions, and the adsorption at neutral pH.

It was found that the adsorption mechanism of 1:1 pre-metallised acid dyes
was different at neutral pH to that at acid pH. It was also found that both the adsorption mechanism and diffusion characteristics of coppered direct dyes were different to that of uncoppered direct dyes, the coppered directs being adsorbed by a site specific mechanism whereas the uncoppered direct dyes were not. This led to the conclusion that a metal complex was formed between the central metal ion in the dye molecule and the chitin or chitosan chain, the amine groups acting as ligands for the available co-ordination sites. The diffusion coefficient for C.I. Direct Blue 15 on chitosan film was determined.

The amine groups available within the polymer chains of wool and nylon were proposed as possible sites for metal complex formation and this was also found to be the case for these polymers.

Item Type: Thesis
Creators: Mazengarb, S.A.
Date: 2002
ISBN: 9781369317046
Divisions: Schools > School of Art and Design
Record created by: Linda Sullivan
Date Added: 01 Oct 2020 14:19
Last Modified: 20 Sep 2023 09:36
URI: https://irep.ntu.ac.uk/id/eprint/41074

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