Sinteza in karakterizacija maghemitnih nanodelcev iz železovega oksalata

diplomsko delo univerzitetnega študijskega programa I. stopnje

Sara Raduha (Avtor), Matjaž Kristl (Mentor), Irena Ban (Komentor)

Povzetek

Namen diplomskega dela je pri sobni temperaturi sintetizirati prekurzor, natančneje železov oksalat dihidrat, Fe2C2O4·2H2O ter ga s pomočjo termičnega razkorja pretvoriti v maghemit. Sledila je uporaba sintetiziranega maghemita, natančneje je cilj maghemitne nanodelce prevleči z dvema različnima surfaktantoma, citronsko kislino in PEG-COOH. Ugotovili smo, da z eksperimentom brez inertne atmosfere ne dobimo željenega produkta. Problem se je pokazal ob dodatku FeSO4·7H2O, saj se je Fe2+ ob prisotnosti kisika oksidiral v Fe3+. Posledično smo uporabili argovo atmosfero ter z njim preprečili oksidacijo Fe. Dobili smo željen produkt, Fe2C2O4·2H2O. Sama pretvorba prekurzorja v maghemit je prav tako potekala v argonovi atmosferi. Sintetiziran maghemit smo oblekli z citronsko kislino in PEG-COOH. Citronska kislina in PEG-COOH sta surfaktanta, ki ponavadi tvorita stabilno magnetno tekočino. Vendar v našem primeru ni bilo tako, nanodelci so se aglomerirali. Težave pri sintezah s pomočjo železovega oksalata so nas pripeljale do nove sinzete, sinteza maghemitnih nanodelcev v vodnem mediju brez surfaktantov. Pripravili smo si erlenmajerico v katero smo dodali degazirano vode in 0,01 M HCl. Naslednjih 30 min smo prepihovali z argonovo atmosfero ter intenzivno mešali. Sledil je dodatek železovega(III) klorida heksahidrata, FeCl3·6H2O in železovega(II) klorida heptahidrata, FeCl2·7H2O. Po 30 min, nastavimo pH na 11 s pomočjo NaOH. Po koncu reakcije zberemo oborino v časi, kateri dodamo destilirano vodo. S tem pripravimo magnetit za oksidacijo v maghemit. To dosežemo s segrevanjem. Šele s to sintezo smo pridobili maghemit, ki je po oblačenju s surfaktanti tvoril stabilno magnetno tekočino. Produkte smo karakterizirali z rentgensko praškovno difrakcijo (XRD) in termično analizo (TGA).

Ključne besede

maghemit;železov oksalat;rentgenska praškovna difrakcija;XRD;termična analiza;TGA;citronska kislina;PEG-COOH;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2015
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[S. Raduha]
UDK:	66.091.3:620.2:661.8'074.2(043.2)
COBISS:	19123734
Št. ogledov:	1362
Št. prenosov:	71
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Synthesis and characterization of maghemite nanoparticles from iron oxalate
Sekundarni povzetek:	The purpose of my diploma thesis is firstly to synthesize the precursor Fe2C2O4·2H2O, iron oxalate dihydrate, at room temperature and secondly, to transform it to maghemite via the thermal decomposition. Then, the coating of maghemite nanoparticles with two different surfactants, citric acid and PEG-COOH, has followed. The result of the experiment has been that the wanted product cannot be obtained without an inert atmosphere. The problem has occurred when FeSO4·7H2O has been added to the chemical process. Namely, Fe2+ has oxidized into Fe3+ in the presence of oxygen. Therefore, we have used an argon atmosphere and thus the Fe oxidation has been prevented and the wanted product Fe2C2O4·2H2O has been obtained. The transformation of precursor to maghemite has also taken place in the argon atmosphere. The synthesized maghemite has been coated with the citric acid and PEG-COOH. In general, those two surfactants form stable magnetic fluid. However, this has not been the case in our experiment as the nanoparticles have agglomerated. Problems, having arisen in iron oxalate syntheses, have led us to a new synthesis which is a synthesis of maghemite nanoparticles in a water medium without surfactants. For the synthesis, we have prepared an Erlenmeyer flask in which we have poured some degassed water and 0,01 M HCl. For the next thirty minutes, we have been blowing with the argon atmosphere and mixing intensively. Then, iron(III) chloride hexahydrate FeCl3·6H2O and iron (II) chloride heptahydrate FeCl2·7H2O have been added. After thirty minutes, a pH value has been set to 11 with the help of NaOH. At the end of the reaction, the precipitate has been collected in a flask to which some distilled water has been added. In this way, magnetite has been prepared to be oxidized to maghemite. That is achieved by heating. It is with the above described synthesis that we have obtained the maghemite which has formed stable magnetic fluid after having been coated with the surfactants. The products have been characterized with X-ray powder diffraction (XRD) and with a thermogravimetric analysis (TGA).
Sekundarne ključne besede:	maghemite;iron oxalate;X-ray diffraction;XRD;thermogravimetry;TGA;citric acid;PEG-COOH;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Diplomsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	VIII, 30 str.
ID:	8889426