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Fotokatalitsko čiščenje zraka s TiO [sub] 2
Matic Račič, 2013, undergraduate thesis

Found in: osebi
Keywords: fotokataliza, napredne oksidacijske metode, titanov dioksid, porozni nosilci, diplomske naloge
Published: 15.10.2013; Views: 2860; Downloads: 180
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Določitev optimalne vsebnosti titanove sadre v cementu
Monika Balažič, 2009, undergraduate thesis

Found in: osebi
Keywords: diplomske naloge, cement, naravna sadra, titanova sadra
Published: 15.10.2013; Views: 2596; Downloads: 155
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Laboratorijska sinteza z železom modificiranih zeolitov za katalitske aplikacije
Matej Mercina, 2011, undergraduate thesis

Found in: osebi
Keywords: diplomske naloge, anorganska sinteza, porozni materiali, železovi silikati, železovi aluminosilikati
Published: 15.10.2013; Views: 2732; Downloads: 222
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Tržna analiza čistilcev zraka z vgrajenimi filtri na osnovi fotokatalize
Filip Križman, 2010, undergraduate thesis

Found in: osebi
Keywords: diplomske naloge, tržna analiza, fotokataliza, čistilci zraka, filtri, titanov dioksid
Published: 15.10.2013; Views: 3809; Downloads: 323
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Imoblizacija [!] TiO [spodaj] 2 in ZnO nanodelcev na porozne silikatne nosilce
Neža Milic, 2011, undergraduate thesis

Found in: osebi
Keywords: napredne oksidacijske metode, titanov dioksid, imobilizacija, nanodelci, organska onesnaževala, diplomske naloge
Published: 15.10.2013; Views: 3258; Downloads: 194
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Development of Advanced TiO2/SiO2 Photocatalyst for Indoor Air Cleaning
Andraž Šuligoj, 2015, doctoral dissertation

Abstract: TiO2 - SiO2 composites were synthesized by low-temperature sol-gel impregnation method, using four different titania sources (P-25 from Degussa, PC500 from Millennium, CCA 100 AS and CCA 100 BS from Cinkarna, later denoted as AS and BS, respectively) and deposited on aluminium and glass carriers. Ordered and disordered mesoporous silicas were impregnated with ce{TiO2} in powder or suspension form in the Ti : Si molar ratio 1 : 1. Structure, size, band gap, chemical composition and specific surface area of nanoparticles were determined by X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DR-UV-vis), Fourier transform infrared spectroscopy (FT-IR) and ce{N2} physisorption. Additionally, quantity of surface hydroxyl groups, surface acidity and mechanical stability of the coatings were determined by temperature programmed Fourier transform infrared spectroscopy (TPD-IR) and Wolff-Wilborn method, respectively. The photocatalytic activity of TiO2 and TiO2 - SiO2 composites was evaluated in the photodegradation of toluene and formaldehyde, as model VOCs, under UVA light irradiation in lab-made photoreactor system with two different regimes; batch and plug-flow mode. These two VOCs are being considered as examples of two of the six major classes of indoor air contaminants. Adsorption properties of the samples with toluene, have shown that the addition of mesoporous silica was beneficial. The increase of the adsorption of the bare AS TiO2 (9.5 %) was higher in the case of ordered silica, SBA-15 (2.8 times for AS/SBA15 to 26.8 %) than disordered SiO2 KIL-2 (2.4 times for AS/KIL2 to 22.7 %) although it was significant in both types of mesoporous silica supports (over 20 %). Adsorption was found to be dependent mostly on the quantity of surface Si-OH groups. Regarding the photocatalytic activities towards toluene degradation, the results with pure TiO2 showed the fastest kinetics in case of sample AS followed by PC500 and P25. The observed behaviour was ascribed to smaller particle size, and consequently higher specific surface area. Grafting titania onto silica showed the importance of structural parameters. Most importantly, if the pore structure of bare TiO2 collapsed, this resulted in decreased activity. On the other hand, retainment of the pore structure improved the distribution of nanoparticles, crystallinity and optical properties, which resulted in improved photocatalytic activity. In the degradation of formaldehyde, it was found that adsorption and degradation abilities of the materials were much more dependent on the structural properties of the samples, i.e., the pore structure. This was explained as a consequence of the different degradation mechanisms of both pollutants. Toluene degradation is governed by the oxidation through photogenerated holes - direct oxidation, whereas in the degradation of formaldehyde, the major oxidative species are OH radicals. In addition, the same as in toluene oxidation, the activity was dependent mainly on the number of crystal defects and the band gap values, that is the oxidation and reduction potentials of the catalysts. The degradation efficiency was increased from 88 % in pure AS TiO2 to 97 % when this titania was grafted onto colloidal silica (7C). An important highlight of the thesis is synthesis of a novel photocatalyst, labelled AS7C, which comprises an acidic colloidal suspension AS as TiO2 source and colloidal silica, using a low-temperature sol-gel impregnation method. This sample used all the above mentioned properties that improve photocatalytic activity towards both pollutants. Mechanical stability of the samples was also tested. The tests showed that binder, in the form of colloidal SiO2 (in size of 25 nm) in combination with colloidal titania of appropriate size - 6 nm, produced the highest mechanical stability of the coatings, which also showed excellent photocatalytic activity. Stability of the coatings, using AS as titania source, was greatly improved. The Wolff-Wilborn test on AS coating showed no mechanical resistance, while with the optimal (in terms of photocatalytic performance) addition of 7C SiO2 binder stability was excellent (F, which is in the middle of 6B-6H hardness scale). This sample (AS7C) was also tested for release of aerosols, during operation of the reactor, which could be harmful for human health at longer exposure times. It was found that aerosols are formed, probably as a consequence of detachment of nanoparticles in the first period of photodegradation test. However, their formation in consecutive tests was greatly reduced. Last but not least, a pilot plug-flow reactor was constructed to test the photocatalyst's efficiency in one-pass degradation of toluene. Sample AS7C was able to degrade toluene at conditions applied (v= 400 mL/min, m(catalyst) = 1049 mg, C(0) = 1 ppmv), which means that the out-flow from reactor was clean of the pollutant and any possible intermediates, comprising only of humid air and CO2. Deactivation of the catalyst was found at higher air flow and higher initial concentration of the pollutant. However, the concentrations of pollutants in living conditions are few orders of magnitude lower, hence this is a promising result.
Found in: osebi
Keywords: Air remediation, TiO2 photocatalysis, Immobilization, Thin layers, TiO2/SiO2 composites
Published: 31.08.2015; Views: 4258; Downloads: 72
.pdf Fulltext (33,47 MB)

Tatjana Kobal, 2016, master's thesis

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.
Found in: osebi
Keywords: : SiO2 aerogels, manganese-functionalized SiO2 aerogels, sol–gel process, CO2 supercritical drying
Published: 02.09.2016; Views: 2497; Downloads: 137
.pdf Fulltext (4,37 MB)

Zamenjava obstoječih reaktivnih barvil v tiskarni tekstilne tovarne
Gašper Čefarin, 2017, undergraduate thesis

Abstract: Dandanes se v tekstilni industriji uporabljajo različna barvila za barvanje in tiskanje tekstila. Različne vrste barvil se razlikujejo po kemijskih in fizikalnih lastnostih. Manjše razlike, ki imajo v tiskarni lahko velik pomen, so opazne tudi pri barvilih iste vrste različnih proizvajalcev. Pri izbiri barvil je potrebno biti pozoren na to, kakšen ton ima barva na tekstilu, koliko je barva čista ali motna, ter kakšna koncentracija barvila je potrebna, da dosežemo določeno svetlost barve. Cilj barvanja in tiskanja v tekstilni tovarni je namreč velikokrat tudi poustvariti določeno barvo na tekstilu, ki si jo kupec zaželi. To izvedejo tako, da barvila različnih barv zmešajo skupaj v pravem razmerju, pri čemer uporabljajo različno opremo in računalniške programe. V podjetju Tekstina so se odločili za primerjavo do sedaj uporabljanih barvil s cenejšimi barvili drugega dobavitelja. Menjava barvne palete barvil je proces, ki zahteva svojevrsten projekt ovrednotenja ter medsebojne primerjave barvil različnih proizvajalcev in sicer čimbolj natančno, tako z vidika nastalih barv na tekstilu pri tiskanju, ter s finančnega, tehnološkega in okoljskega vidika. Namen diplomske naloge je prikazati, ali je zamenjava obstoječih reaktivnih barvil z novimi v tiskarni tekstilne tovarne smotrna. V okviru diplomske naloge sem izvedel primerjalni tisk in primerjal nastale barve na tekstilu ter razlike v ceni, vplivih na okolje ter tehnološke lastnosti barvil oziroma kvaliteto barvil obeh dobaviteljev. Ugotovil sem, da bi bila najbolj smotrna menjava treh barvil, ki so v tiskarni podjetja količinsko najbolj uporabljana, menjava ostalih barvil pa zahteva dodatno presojo s strani izkušenih ljudi in strokovnjakov na tem področju.
Found in: osebi
Keywords: tekstilna industrija, tiskarna, tiskanje, reaktivna barvila, barvna paleta, zamenjava dobavitelja
Published: 25.09.2017; Views: 1460; Downloads: 95
.pdf Fulltext (2,84 MB)

Boštjan Gerbec, 2018, master's thesis

Abstract: V magistrskem delu smo obravnavali problematiko zavržene hrane v Slovenji ter širše. V Sloveniji vsako leto zavržemo 73 kilogramov hrane na prebivalca, podatki zadnjih let pa kažejo na naraščanje teh količin. Polovico zavržene hrane ustvarijo gospodinjstva. Ker je hrana nepogrešljiva za življenje, veliko ljudi pa živi v pomankanju, je takšno stanje zaskrbljujoče in nas kot družbo ne prikazuje v najboljši luči. Pri razumevanju problema in pri iskanju rešitev smo poleg pregleda zakonodaje in znanstvene literature izvedeli tudi raziskavo na primeru mlečnih izdelkov. Uporabili smo tri raziskovalne pristope: anketo, intervju ter eksperiment s preizkusom izdelka. Ugotovili smo, da je literatura v večini dostopna le v obliki znanstvenih člankov in študij, prav tako še do nedavnega ni bilo sistematičnega zbiranja in vodenja evidenc o količinah zavržene hrane. V nalogi smo predlagali ukrepe in načine, kako bi lahko zmanjšali količino zavržene hrane, in izpostavili velik pomen tega, da vsak posameznik začne pri sebi. Ustrezno je treba nakupovati hrano, planirati obroke ter hrano tudi pravilno shranjevati. V nalogi smo tudi predstavili različne primere dobrih praks, ki prav tako pomagajo zmanjševati količino zavržene hrane, bodisi v Sloveniji bodisi v tujini. V nalogi smo potrdili hipotezo, ki smo jo izpostavili na začetku, da se lahko količina zavržene hrane v Slovenji zmanjša. Potrošniki lahko na to neposredno vplivamo v domačih gospodinjstvih. S spremembami nakupovalnih navad pa lahko v določeni meri vplivamo tudi na trgovce in na njihovo ponudbo živil. Na problem hrane, ki se izgublja v proizvodnem in distribucijskem delu življenjskega cikla, pa v širšem smislu lahko vplivajo tako vlade vseh držav kot tudi mednarodna skupnost.
Found in: osebi
Keywords: zavržena hrana, zakonodaja, gospodinjstva, primer zavrženih mlečnih izdelkov, zmanjševanje odpadne hrane z ozaveščanjem, zmanjševanje odpadne hrane z državnimi politikami
Published: 14.09.2018; Views: 931; Downloads: 65
.pdf Fulltext (1,96 MB)

Photocatalytic activity of Zr and Mn co-doped TiO2 in aqueous media
Urška Lavrenčič Štangar, O. L. Pliekhov, Nataša Novak Tušar, 2015, published scientific conference contribution abstract

Found in: osebi
Keywords: mechanism, influence of dopants, Mn scavenger of hydroxyl radicals
Published: 01.02.2016; Views: 1887; Downloads: 1
.pdf Fulltext (4,20 MB)

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