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Title:Stabilnost in detekcija železovih ionov v vodi iz oblakov
Authors:Gelati, Jasna (Author)
Korte, Dorota (Mentor) More about this mentor... New window
Files:.pdf Jasna_Gelati.pdf (2,39 MB)
 
Language:Slovenian
Work type:Bachelor thesis/paper (mb11)
Tipology:2.11 - Undergraduate Thesis
Organization:FZO - Faculty of Environmental Sciences
Abstract:Izmed vseh prehodnih kovin je železo najbolj razširjen in najbolj reaktiven element v atmosferski tekoči fazi, ki ima ključno vlogo v vodni kemiji. Oksidacijsko stanje železa se lahko v raztopini spremeni, npr. železo v obliki Fe(II) se ob stiku z zračnim kisikom ali drugim oksidantom oksidira do Fe(III) in se izloči kot netopni hidratizirani oksid. Zaradi velikega števila železovih zvrsti in njihovih različnih stabilnosti je kompleksna kemija železa v vodnih raztopinah še slabo raziskana. Tako npr. v vodi iz oblakov (to je voda iz kapljic, ki tvorijo oblake) še niso bile izmerjene koncentracije in konstante stabilnosti železovih zvrsti z organskimi ligandi, ki so ključnega pomena za poznavanje topnosti železa v vodi iz oblakov in lahko dajo pomembne podatke o kemijskih procesih v atmosferi. V diplomski nalogi sem določevala optimalne pogoje obdelave vzorcev in njihovega shranjevanja za ohranitev razmerij železovih zvrsti v vodi iz oblakov pri uporabi UV-Vis-spektrofotometrije (SPEC) ter mikroskopije s toplotnimi lečami (TLM). Dokazali smo, da shranjevanje vzorcev pri temperaturi 4 C in v temi zagotavlja največjo stabilnost Fe(II) in Fe(III) tako v kopenski kot morski vodi iz oblakov. Konstanta rekcijske hitrosti pretvorbe ali izgube Fe(II) oziroma Fe(III) ionov (Kp) v morski vodi iz oblakov znaša -0,215 s-1, v kopenski vodi iz oblakov pa -0,067 s-1, kar je manj v primerjavi s shranjevanjem pri sobni temperaturi in na svetlobi, saj tam Kp v morski vodi iz oblakov znaša -0,319 s-1, kopenski vodi iz oblakov pa -0,210 s-1. Z izračunom spodnje meje določevanja (LOD) za SPEC in TLM metodo smo pokazali, da je zaradi nižje LOD-vrednosti TLM-metoda primernejša za detekcijo železovih zvrsti v vodi iz oblakov, ker lahko uporabimo manjše količine vzorcev (µL), katerih koncentracije so tudi lahko nižje od LOD, ki jo lahko dosežemo s SPEC.
Keywords:TLM, UV-Vis-spektrofotometrija, voda iz oblakov, Fe(II), Fe(III)
Year of publishing:2016
Source:Nova Gorica
COBISS_ID:4497659 Link is opened in a new window
URN:URN:SI:UNG:REP:2MJDXFDM
Views:3297
Downloads:167
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Secondary language

Language:English
Title:Stability and detection of iron ions in cloud water
Abstract:Among all transition metals, iron is the most abundant and the most reactive in the atmospheric liquid phase with a crucial role on the aqueous chemistry. The oxidation state of iron alters its reactivity in solution, for example, iron in the form of Fe(II) in contact with the air of oxygen or other oxidizing agent is oxidized to Fe(III) and forms insoluble hydrated oxide. Given the large number of iron species and their different stability, the complex chemistry of iron in aqueous solutions is still poorly researched. Thus, for example in water from the clouds concentration and stability constants of iron species with organic ligands have not been measured yet, which are crucial for understanding the solubility of iron in the water from the clouds and can give important information about chemical processes in the atmosphere. In this study, the optimal conditions for processing the samples and their storage to maintain the ratios of iron species in the water from the clouds constant, were determined by the use of the UV-Vis spectrophotometry (SPEC) and the thermal lens microscopy (TLM). It was demonstrated, that storage of samples at temperature of 4°C provides maximum stability of Fe(II) and Fe(III) in both land and marine cloud the water. A in sea cloud water is -0.215 s-1 whereas in land cloud water -0.067 s-1, which is less in comparison to the storage conditions at room temperature and in light, where the value of the are -0.319 s-1 and -0.210 s-1 in sea cloud water and in land cloud water, respectively. By calculating the lower limit of determination (LOD) for SPEC and TLM method, it was shown, that due to the lower LOD value the TLM method is suitable for the detection of iron species in water from the clouds, because the requirements of typically smaller quantities of samples whose concentration can also be less than LOD, which can be achieved by SPEC.
Keywords:TLM, UV-Vis spectrophotometry, water from clouds, Fe(II), Fe(III)


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