Title Sinteza i karakterizacija PEDOT/TiO2 nanokompozitnog fotokatalizatora Title (english) Synthesis and characterization of PEDOT/TiO2 nanocomposite photocatalyst Author Magdalena Vujasinović Mentor Zvonimir Katančić (mentor)Committee member Zvonimir Katančić (predsjednik povjerenstva)Committee member Zlata Hrnjak-Murgić (član povjerenstva)Committee member Marijana Kraljić Roković (član povjerenstva)Granter University of Zagreb Defense date and country 2019-07-01, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Otpadne vode značajan su ekološki problem i u pravilu su visoko opterećene različitim vrstama i količinama onečišćivala. Takve vode nisu pogodne za korištenje te zahtijevaju odabir i primjenu tehnologije obrade voda kako bi se postigla zadovoljavajuća kvaliteta obrađene vode. Najčešće metode obrade otpadnih voda jesu biološke, mehaničko-fizikalne i kemijske metode. U slučaju organskog onečišćenja pokazalo se da je najučinkovitija primjena naprednih oksidacijskih procesa (kemijske metode) – proces ozonizacije, Fentonov proces i proces fotokatalize. Proces fotokatalize temelji se na razgradnji onečišćenja uz dodatak fotokatalizatora pod utjecajem svjetlosti, a u radu je kao fotokatalizator korišten titanijev dioksid (TiO2). TiO2 sadrži široku zabranjenu zonu te je aktivan samo pod UV svjetlom zbog čega se sintetizira u kombinaciji s elektrovodljivim polimerima čija je zabranjena zona mala i time se proširuje fotokatalitička aktivnost u vidljivi dio spektra. Osim elektrovodljivim polimerima zabranjena zona može se smanjiti dodatkom ionomera - polielektrolita koji se sastoje od više ionskih skupina kao što je polistiren sulfonska kiselina (PSS). U radu je, metodom kemijske oksidacijske polimerizacije uz prisutnost FeCl3 kao oksidansa, sintetiziran nanokompozitni fotokatalizator elektrovodljivog polimera poli(3,4-etilendioksitiofen) (PEDOT) i titanijevog dioksida uz molarni omjer monomera EDOT-a i TiO2 1:30. Također, istom metodom, ali uz dodatak polistiren sulfonske kiseline (PSS) sintetizirani su PEDOT/TiO2 nanokompozitni fotokatalizatori omjera 1:20 i 1:30. Karakterizacija je provedena termogravimetrijskom analizom (TGA), infracrvenom spektroskopijom s Fourierovim transformacijama (FT-IR) i ispitivanjem morfološke strukture pretražnom elektronskom mikroskopijom (SEM). Fotokatalitička učinkovitost ispitana je praćenjem uklanjanja azo bojila Acid Blue 25 (γ = 30 mg/L) u vodi, pri različitom pH (4,5; 6,3; 8,0) uz simulirano Sunčevo zračenje i UV-A zračenje mjerenjem apsorbancije na UV/ViS spektrofotometru. Rezultati su pokazali da razgradnja bojila ovisi o omjeru EDOT-a i TiO2, a najveća učinkovitost je postignuta pri neutralnim ili blago kiselim uvjetima.
Abstract (english) Wastewaters are significant environmental problem as they usually contain various types and quantities of pollutants. Such water is not suitable for use and it requires application of wastewater treatment technology to achieve satisfactory quality of treated water. The most common methods of wastewater treatments are biological, mechanical/physical and chemical methods. In case of organic contamination, the application of advanced oxidation processes (chemical methods) - the ozonization process, the Fenton process and the photocatalytic processes, proved to be the most effective. The photocatalysis process is based on degradation of contamination with the addition of photocatalyst under the influence of light, where titanium dioxide (TiO2) is used as a photocatalyst in this work. TiO2 contains a wide band gap and is therefore active only under UV light, which is why it can be synthesized in combination with conductive polymers which have a small band gap and thus they expand photocatalytic activity of TiO2 into the visible part of the spectrum. Apart from conducting polymers, the band gap can be reduced by adding ionomers - polyelectrolytes consisting of several ionic groups such as polystyrene sulfonic acid (PSS). In this paper, a nanocomposite photocatalyst of the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and titanium dioxide was synthesized by chemical oxidative polymerization method. Molar ratio of EDOT monomer and TiO2 was 1:30 while FeCl3 was used as an oxidant. Using the same procedure, but with the addition of polystyrene sulfonic acid (PSS), PEDOT/TiO2 nanocomposite photocatalysts were synthesized at 1:20 and 1:30 ratios. Characterization was performed by thermogravimetric analysis (TGA), infrared spectroscopy with Fourier transform (FT-IR) and by examination of morphological structure using scanning electron microscopy (SEM). The photocatalytic efficiency was tested by monitoring the removal of azo dye Acid Blue 25 (γ = 30 mg / L) in water at different pH (4.5, 6.3, 8.0) under the simulated solar or UV-A irradiation by measuring the absorbance at UV/Vis spectrophotometer. The results showed that dye degradation depends on EDOT and TiO2 ration while best efficiency was obtained at neutral or slightly acid conditions.
Keywords
otpadne vode
fotokataliza
PEDOT
titanijev dioksid
Acid Blue 25 bojilo
Keywords (english)
wastewaters
photocatalysis
PEDOT
titanium dioxide
Acid Blue 25 dye
Language croatian URN:NBN urn:nbn:hr:149:087353 Project Number: IP-2013-11-5092 Study programme Title: Environmental Engineering - Undergraduate study Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2023-05-29 12:08:47
