20.500.12556/RUL-162500 NASTANEK ORGANSKIH KISLIN MED RAZGRADNJO LIGNINSKEGA PAPIRJA Production of organic acids during degradation of lignin-containing paper Kislinsko katalizirana hidroliza in oksidacija sta glavna procesa razgradnje papirja. Med razgradnjo se v papirju akumulirajo organske kisline, ki pospešujejo kislost papirja, kar pospešuje hidrolizo. Posledice hidroliznih in oksidacijskih procesov lahko povzročijo izgubo knjižne dediščine. V starem papirju najdemo metanojsko, etanojsko, mlečno, sukcinsko, glikolno, oksalno in druge kisline oz. njihove anione. Čeprav so to pretežno šibke kisline, je njihov vpliv zaradi visoke koncentracije lahko znaten. V pričujočem delu sem z različnimi metodami pospešene razgradnje s pomočjo ionske kromatografije spremljal koncentracije izbranih kislin v realnih vzorcih papirja. Med razgradnjo sem spremljal barvo papirja in določil spremembo pH-vrednosti ob koncu eksperimenta. Na podlagi pridobljenih podatkov sem proučil vpliv eksperimentalnih pogojev (temperatura, relativna vlažnost, trajanje eksperimenta) na koncentracijo nastalih kislin, barvo in pH-vrednost papirja. Primerjal sem dve metodi pospešene razgradnje in ugotovil, da konvencionalna metoda, pri kateri je vzorec izpostavljen toku zraka, podcenjuje spremembo barve in pH. Razlike pri koncentraciji organskih kislin niso znatne. Ovrednotil sem vpliv lignina na merjene parametre. Acid-catalysed hydrolysis and oxidation are the main pathways of paper degradation. During degradation, organic acids accumulate in the paper, which increases the acidity of the paper and accelerates hydrolysis. The consequences of these two processes can lead to the loss of the written cultural heritage. Methanoic, ethanoic, lactic, succinic, glycolic, oxalic, and other acids or their anions are found in historical papers. Although these are weak acids, their effects can be considerable due to their high concentration. In this work, I monitored the concentration of selected acids in differently artificially aged historical paper samples using ion chromatography. During degradation, I monitored the colour of the paper and measured the differences in the pH of the paper at the end of the experiment. Based on the obtained data, I investigated the influence of the experimental conditions (temperature, relative humidity, duration of the experiment) on the concentration of the formed acids, colour, and pH of the paper. acids formed and the colour of the paper. I compared two different methods of accelerated degradation and found that the conventional method, where the sample is exposed to an airflow, underestimates the change in colour and pH. The differences in the concentration of organic acids are not significant. I evaluated the impact of lignin on the measured parameters. papir lignin ionska kromatografija kolorimetrija kemometrija paper lignin ion chromatography colorimetry chemometrics true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2024-09-24 12:55:01 2024-09-24 12:55:10 2024-11-22 11:21:42 0000-00-00 00:00:00 2024 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 25318 216098563 Ocepek_Jan_-_NASTANEK_ORGANSKIH_KISLIN_MED_RAZGRADNJO_LIGNINSKEGA_PAPIRJA.pdf Ocepek_Jan_-_NASTANEK_ORGANSKIH_KISLIN_MED_RAZGRADNJO_LIGNINSKEGA_PAPIRJA.pdf 1 0B8FB408AB6915650EB4A7EE3B2AF770 68e1561bfbb9786f761e6c1ab01ae822343a74af0da74eda6ee1c650dbcaf3a2 5b46c7ac-7a63-11ef-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=191844 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0