Re-use of waste wool fibers by chemical treatment-Enhancement of deodorization perfixmance by oxidation and reduction

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Wool fibers were oxidized with performic acid, where cysteic acid residues were formed from cysteine residues in wool keratin. Wool fibers were also reduced with 2-mercaptoethanol, where cysteine residues were formed from cysteine residues. Amines sorption of the oxidized wool fibers and ethylmercaptan sorption of the reduced wool fibers were evaluated with gas chromatography and/or the method using aluminum bag and a gas-detecting tube. The oxidation of wool fibers remarkably improved the sorption of ammonia. Ammonia gas (4000ppm) in a 500mL Erlenmyer flask was completely sorbed in oxidized wool fibers in 60m. This shows that sulfonic acid group which was formed in wool by oxidation effectively acts in sorption of ammonia. The sorption of CnH2n+iNH2 (n=1-4) and (CH3)nNH3-n (n=2, 3) was also evaluated. The longer and the more alkyl substituents on nitrogen of the amine were, the more slowly oxidized wool fibers sorbed the alkylamines. This is probably due to its hydrophobic steric hindrance. Ammonia sorption of oxidized wool fibers deteriorated gradually after repetition-use. Though succinylation of oxidized wool fibers showed no effect on absorption of ammonia at first use, oxidized and succinylated wool fibers sorbed more ammonia than oxidized ones after the repetition-use. This suggests that sulfonic acid group in wool keratin more quickly binds with ammonia than carboxylic group.Reduction of wool fibers showed a little effect on absorption of ethyl mercaptan : ethyl mercaptan (80ppm) over reduced wool fibers in aluminum bag of 4L volume decreased by 3-15% after 6 h. Water content of reduced wool fibers had influence on the sorption of ethylmercaptan. Reduced wool fibers of which water content was 100%, showed the highest sorp ability.