Untersuchungen zur Sorption von Innenraum-Luftschadstoffen durch Wolle

This dissertation concerns itself with the sorption behaviour of wool concerning some important interior air pollutants. Apart from the intake of toluol as an organic substance frequently provable in high concentrations in the interior air, the sorption and possible reactivity of several aldehydes were examined. The emphasis of the investigation is on formaldehyde as the most important and most frequent aldehyde occurring in interiors. Under static conditions of 22°C wool takes up large quantities of formaldehyde from the gaseous phase. The sorption follows a first order kinetic. The sorption activity rises with increasing relative humidity and falling pH-value. The intake quantity after long exposition times however is not altered by relative humidity or low pH. We have thus a kinetic effect which leads to a rise of the velocity coefficient by a factor of 6.6 at a relative humidity between 30 and 90%. Desorption experiments could demonstrate that the release of formaldehyde is decelerated and that wool fibre has a high retention capability. The release of formaldehyde decreases with rising retention time (reaction time) in the fibre. The relative amount of hydrolytically separable formaldehyde also depends on the reaction time in the wool and continues to diminish after long reaction times (eight months). A possible explanation of these results is a varying bond strength of formaldehyde to the amino acids of wool proteins. Apart from the physical bond there is a reaction of formaldehyde with proteins via the intermediate stages of methylol bonds and bases to irreversible methylene bonds. The formation of these stable methylene derivatives takes place over several months under typical conditions (22°C, 56% relative humidity and pH-value 7,6. The formation can be accelerated by higher temperature and a lower pH-value of the wool. It could be shown through electrophoretic fractioning of extracted wool proteins that the relative humidity has little influence on the formation of methylene interlacing. A rise of the temperature to 50°C however leads to strong interlacing after a short time. At 22°C it takes a long reaction time with the wool protein to reach a distinct increase of interlacing. This is accelerated by an acidic pH-value of the wool. The interlacing of the wool proteins starts in the intermediary filaments (IF) and extends to the other morphologic components of the cortex when the exposition temperature or the concentration are increased. The non ceratinic parts of the wool fibre are also linked by formaldehyde. This can be shown by the decrease of the enzymatical degradability of the fibre proteins through the enzymatical alloy Pronase.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2006

Author dc:creator

• Thomé, Stefan

Contributors dc:contributor

• Höcker, Hartwig

• info:eu-repo/classification/ddc/540
• Wolle
• Sorption
• Desorption
• Formaldehyd
• Aldehyde
• Toluol
• Raumluft
• Keratine
• Sorptionskinetik
• Vernetzung
• Chemie
• Luftschadstoffe
• Sorptionsisotherme
• Luftwechselrate

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122928%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:61250