magistrsko delo
Tomaž Mržljak (Avtor), Irena Kralj Cigić (Mentor), Jurij Lah (Član komisije za zagovor), Matija Strlič (Član komisije za zagovor)

Povzetek

Kulturna dediščina je v muzejih, galerijah in ostalih ustanovah, kjer shranjujejo zgodovinske predmete, podvržena postopni razgradnji zaradi prisotnosti hlapnih organskih spojin (HOS). Ogroženi so predmeti iz vseh vrst materialov, kot so kovine, kamnine, steklo, papir, barvila … Največja koncentracija HOS je v zaprtih prostorih, kot so vitrine, omare, predali ipd. Izvor največje količine onesnažil je les, ki emitira predvsem formaldehid, metanojsko in etanojsko kislino. Zaradi porasta novih materialov se, poleg teh treh, v muzejski atmosferi nahajajo tudi druga onesnažila, katerih problematičnih učinkov še ne poznamo. Zaradi vse večje ogroženosti predmetov so številne raziskave usmerjene v preučevanje izvorov, koncentracije in problematičnih učinkov korozivnih spojin. Poleg tega so raziskave usmerjene tudi v to, kako preprečiti pojavnost večjih koncentracij hlapnih organskih spojin v prisotnosti zgodovinskih predmetov. Možnosti je veliko, med drugim uporaba gradbenih materialov, ki nase vežejo spojine, uporaba pohištvenih materialov, ki bi emitirali manj problematičnih spojin (npr. kovine in steklo), ventilacija prostorov, zatesnitev zaprtih prostorov itd. Ena od možnosti, kako v majhnih in tesno zaprtih prostorih preprečiti, da bi koncentracija onesnažil močno narasla, je tudi uporaba t. i. sorbentov. Gre za snovi, ki nase predvsem s fizisorpcijo vežejo spojine. Cilj moje magistrske naloge je bil karakterizacija desetih sorbentov, ki bi jih lahko potencialno uporabili za zaščito kulturne dediščine. Zanimalo me je, ali so testirani sorbenti primerni za to, da so v bližini zgodovinskih predmetov, saj bi tudi sami sorbeni lahko emitirali onesnažila, ki bi bila lahko korozivna. Sestava devetih sorbentov je bila neznana, znan vzorec je bil le aktivno oglje, ki je eden najbolj razširjenih sorbentov, zato sem pričakoval, da se bo tudi v mojem primeru izkazal kot uporaben in neproblematičen, kar so potrdili eksperimenti. Ustreznost sorbentov sem preveril s t. i. Oddyjevim testom, pospešenim korozijskim testom, ki pri pogojih 100 % relativne vlažnosti in temperaturi 60 ºC pokaže, ali določena snov izloča spojine, ki bi lahko korodirale svinec, srebro ali baker. Zanimalo me je tudi, katere spojine bi lahko povzročile korozijo omenjenih treh kovin in prav tako sestava sorbentov, zato sem izvedel še vzorčenje z mikroesktrakcijo na trdno fazo, kjer sem v viale nameščene sorbente izpostavil segrevanju na vodni kopeli na 60 ºC. Identifikacijo vzorčenih spojin sem opravil s sklopljeno tehniko plinska kromatografija/masna spektrometrija. Izkazalo se je, da so vsi neznani sorbenti, ki so imeli videz bele zrnaste snovi, emitirali (ciklične) organske dušikove spojine. Primerjava s knjižnico masnih spektrov je pokazala tudi, da prav tako vsi tisorbenti verjetno emitirajo spojino acetaldoksim – s primerjavo ploščin kromatografskih vrhov med različnimi vzorci sem ugotovil, da sorbenti, ki emitirajo največ acetaldoksima, ne opravijo Oddyjevega testa, saj korodirajo baker. S spektroskopijo IR kovinskih ploščic iz Oddyjevega testa sem poskušal dodatno povezati ugotovitve pridobljene z Oddyjevim testom in analizo GC/MS.

Ključne besede

kulturna dediščina;hlapne organske spojine;HOS;Oddyjev test;mikroekstrakcija na trdno fazo;SPME;GC/MS;sorbenti;magistrska dela;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UL FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik: [T. Mržljak]
UDK: 543.544(043.2)
COBISS: 163021315 Povezava se bo odprla v novem oknu
Št. ogledov: 18
Št. prenosov: 8
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: Characterization of sorbents based on VOC emissions
Sekundarni povzetek: Cultural heritage in museums, galleries, and other institutions, where historical objects are stored, is subject to gradual degradation due to the presence of volatile organic compounds (VOCs). Objects made of various materials such as metals, minerals, glass, paper, dyes, etc., are at risk. The highest concentration of VOCs is found in enclosed spaces such as display cases, cabinets, drawers, etc. The primary source of pollutants is wood, which mainly emits formaldehyde, acetic acid, and formic acid. Due to the increase in new materials, besides these three, other pollutants are also present in the museum atmosphere, whose problematic effects are not yet known. Due to the increasing vulnerability of objects, numerous studies are focused on investigating the sources, concentrations, and problematic effects of corrosive compounds. Additionally, research is also directed towards preventing the occurrence of high concentrations of VOCs in the presence of historical objects. There are various options, including the use of building materials that bind compounds, the use of furniture materials that emit fewer problematic compounds (e.g., metals and glass), room ventilation, sealing of enclosed spaces, etc. One of the options to prevent a significant increase in pollutant concentrations in small and tightly enclosed spaces is the use of so-called sorbents. These substances primarily bind compounds through physisorption. The goal of my master's thesis was to characterize ten sorbents that could potentially be used for the protection of cultural heritage. I was interested in whether the tested sorbents were suitable to be located near historical objects, as the sorbents themselves could emit pollutants that could be corrosive. The composition of nine sorbents was unknown, with activated carbon being the only known sample, which is one of the most common sorbents. Therefore, I expected it to be useful and nonproblematic in my case, which was confirmed by experiments. I assessed the suitability of the sorbents using the Oddy test, an accelerated corrosion test that, under conditions of 100% relative humidity and a temperature of 60 °C, indicates whether a certain substance releases compounds that could corrode lead, silver, or copper. I was also interested in identifying the compounds that could cause corrosion in these three metals and the composition of the sorbents. Therefore, I performed solid-phase microextraction sampling, where I exposed the sorbents placed in vials to heating in a water bath at 60 °C. I identified the sampled compounds using gas chromatography/mass spectrometry. It turned out that all the unknown sorbents, which appeared as white crystalline substances, emitted (cyclic) organic nitrogen compounds. Comparison with the mass spectrometry library also showed that all of these sorbents likely emit the compound acetaldoxime. By comparing the areas of chromatographic peaks among different samples, I found that the sorbents emitting the most acetaldoxime fail the Oddy test, as they corrode copper. I attempted to further correlate the findings obtained from the Oddy test and GC/MS analysis by using IR spectroscopy of metal plates from the Oddy test.
Sekundarne ključne besede: VOCs;Oddy test;SPME;GC/MS;sorbents;Organski onesnaževalci;Kromatografija;Univerzitetna in visokošolska dela;
Vrsta dela (COBISS): Magistrsko delo/naloga
Študijski program: 1000375
Konec prepovedi (OpenAIRE): 1970-01-01
Komentar na gradivo: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Kemija
Strani: 106 str.
ID: 19904958