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Title:STRUCTURAL PROPERTIES OF MANGANESE-FUNCTIONALIZED SILICA AEROGELS : MASTER'S THESIS
Authors:ID Novak Tušar, Nataša (Mentor) More about this mentor... New window
ID Kobal, Tatjana (Author)
Files:.pdf Tatjana_Kobal.pdf (4,37 MB)
MD5: 667760309022EEC3AE904A863BC09ED6
 
Language:English
Work type:Master's thesis
Typology:2.09 - Master's Thesis
Organization:FPŠ - Graduate School
Abstract:Manganese-functionalized silica with interparticle mesoporosity and isolated Mn sites (Mn/Si = 0.01) is an excellent Fenton catalyst for water cleaning. However, there is a problem that needs to be solved, i.e., Mn leaching from the silica support during the reaction. The solution may lie in using aerogels as the silicate supports for the manganese. The goal of this master thesis is the synthesis and characterization of manganese-functionalized silica aerogels with different Mn/Si molar ratios and a determination of their structural properties. The emphasis is on the preparation of manganese-functionalized silica aerogels with isolated manganese sites. Firstly, manganese-functionalized microporous and mesoporous silicates with a molar ratio Mn/Si = 0.005–0.02 were synthesized according to the literature and characterized as reference materials for manganese-functionalized aerogels. Manganese silicalite-1 (MnS-1) as a microporous zeolite-type silicate and manganese-functionalized silica (MnKIL-2) as a mesoporous silicate were prepared by the sol-gel process with a hydrothermal and solvothermal treatment, respectively. MnS-1 and MnKIL-2 with a molar ratio of Mn/Si ≤ 0.01 contain manganese as isolated sites in the silica framework and with a molar ratio of Mn/Si > 0.01 contain manganese as manganese oxides. Secondly, manganese-functionalized aerogels (MnAEG) with a molar ratio Mn/Si = 0.005–0.02, were prepared according to the acid-base of the sol-gel polymerization of a tetraethylorthosilicate precursor, which is followed in combination with a supercritical drying using CO2. The prepared materials were characterized using the following techniques: X-ray powder diffraction (XRD), energy-dispersive X-ray elemental analysis (EDX), nitrogen physisorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The characterization results on manganese-functionalized aerogels (MnAEG) showed Mn oxide nanoparticles incorporated into the aerogel already at a low Mn concentration (Mn/Si = 0.005), which means that Mn aerogels are not promising silica supports for Mn catalysts applied for water cleaning, because they do not contain isolated Mn sites.
Keywords:: SiO2 aerogels, manganese-functionalized SiO2 aerogels, sol–gel process, CO2 supercritical drying
Place of publishing:Nova Gorica
Year of publishing:2016
PID:20.500.12556/RUNG-2565 New window
COBISS.SI-ID:4488443 New window
NUK URN:URN:SI:UNG:REP:NUYSHZ8W
Publication date in RUNG:02.09.2016
Views:8220
Downloads:245
Metadata:XML DC-XML DC-RDF
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KOBAL, Tatjana, 2016, STRUCTURAL PROPERTIES OF MANGANESE-FUNCTIONALIZED SILICA AEROGELS : MASTER’S THESIS [online]. Master’s thesis. Nova Gorica. [Accessed 19 March 2025]. Retrieved from: https://repozitorij.ung.si/IzpisGradiva.php?lang=eng&id=2565
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Secondary language

Language:Slovenian
Title:STRUKTURNE ZNAČILNOSTI Z MANGANOM FUNKCIONALIZIRANIH SILIKATNIH AEROGELOV : MAGISTRSKO DELO
Abstract:Mezoporozni silikati s poroznostjo med delci, ki vsebujejo mangan na izoliranih mestih (Mn/Si = 0.01) so odlični Fentonovi katalizatorji za čiščenje vode. Njihova slabost je uhajanje mangana iz silikatnega ogrodja med potekom reakcije čiščenja vode, kar preprečuje ponovno uporabo katalizatorja oziroma recikliranje katalizatorja. Silikatni aerogeli bi bili lahko primernejši nosilci katalitsko aktivnega mangana na izoliranih mestih. Cilj magistrskega dela je sinteza in karakterizacija z manganom - funkcionaliziranih silikatnih aerogelov z različnimi molskimi razmerji Mn/Si = 0.005 - 0.02, ter določitev njihovih strukturnih lastnosti. Poudarek je na pripravi silikatnega aerogela z manganom na izoliranih mestih v silikatnem ogrodju. Po literaturnih podatkih sem najprej sintetizirala in okarakterizirala z manganom funkcionalizirane mikroporozne in mezoporozne silikate kot referenčne materiale. Uporabila sem molsko razmerje Mn/Si = 0.005–0.02. Sintetizirala sem manganov silikalit–1 (MnS-1) kot mikroporozni zeolitni tip silikata in manganov silikat s poroznostjo med delci (MnKIL-2) kot mezoporozni tip silikata. Omenjene materiale sem pripravila s kombinacijo sol-gel postopka in hidrotermalne ali solvotermalne sinteze. MnS-1 in MnKIL-2 z molskim razmerjem Mn/Si ≤ 0,01 vsebujeta mangan v obliki izoliranih mest v silikatnem ogrodju in z molskim razmerjem Mn/Si > 0,01vsebujeta mangan v obliki manganovih oksidov. Z manganom - funkcionalizirane silikatne aerogele (MnAEG) z molskim razmerjem Mn/Si = 0.005–0.02 sem pripravila s kislinsko – bazično sol-gel polimerizacijo tetraetilortosilikatnega prekurzorja v kombinaciji z superkritičnim sušenjem z CO2. Pripravljene materiale sem okarakterizirala z rentgensko praškovno difrakcijo (XRD), dušikovo fizisorpcijo, elementno analizo (EDX), vrstičnim elektronskim mikroskopom (SEM) in presevnim elektronskim mikroskopom (TEM). Karakterizacijske metode so pokazale, da je mangan v silikatnih aerogelih (MnAEG) prisoten v obliki nanodelcev manganovega oksida in ne kot mangan na izoliranih mestih že pri zelo nizkem Mn/Si molskem razmerju (Mn/Si = 0.005).To pomeni, da manganovi aerogeli niso obetavni katalizatorji za čiščenje vode.
Keywords:SiO2, manganovi SiO2 aerogeli, sol–gel postopek, superkritično sušenje s CO2


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