Ispitivanje efikasnosti PEDOT/TiO2 kompozitnog fotokatalizatora pri različitim koncentracijama katalizatora tijekom razgradnje Acid Blue 25 bojila

undergraduate thesis

• Title (english): Testing the efficiency of PEDOT/TiO2 composite photocatalyst at different concentration of the catalyst during the decomposition of Acid Blue 25 dye
• Author: Nikolina Nascimento Mrakovčić
• Mentor: Zlata Hrnjak-Murgić (mentor)
• Committee member: Zlata Hrnjak-Murgić (predsjednik povjerenstva)
• Committee member: Zvonimir Katančić (član povjerenstva)
• Committee member: Suzana Sopčić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2017-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

Otpadne vode ekološki su problem zbog različitih organskih spojeva čija prisutnost nije poželjna. Stoga se prije ispuštanja u okoliš moraju obraditi različitim metodama i procesima – mehaničkim uklanjanjem onečišćenja, fizikalnim, biološkim i kemijskim metodama. Napredni oksidacijski procesi (AOP) jedna su od mogućnosti obrade otpadnih voda. Među njima je i fotokataliza, koja uključuje razgradnju onečišćenja katalizatorima pod utjecajem svjetla. Kako TiO2 ima ograničeno djelovanje pod vidljivom svjetlošću zbog velike širine zabranjene zone, kemijskom oksidacijskom polimerizacijom sintetizirani su kompozitni fotokatalizatori vodljivog polimera poli(3,4-etilendioksitiofena) (PEDOT) i TiO2 uz oksidans FeCl3. Kompoziti su sadržavali različite omjere PEDOT-a i TiO2 jer su sintetizirani uz omjere monomera i nanočestica TiO2 1:2, 1:3, 1:4, 1:5, 1:10 i 1:20. Kompozitni fotokatalizatori su karakterizirani FTIR spektroskopijom te UV/Vis spektroskopijom. Fotokatalitička aktivnost ispitana je praćenjem razgradnje Acid Blue 25 (AB25) bojila u vodi uz simulirano Sunčevo zračenje. Tijekom procesa fotokatalize obezbojenje je praćeno određivanjem promjene apsorbancije korištenjem UV/Vis spektrofotometra, a proces mineralizacije AB25 bojila praćen je mjerenjem ukupnog organskog ugljika (TOC). Rezultati ispitivanja pokazali su kako se povećanjem koncentracije katalizatora povećava učinkovitost fotokatalize i povećava se prividna brzina razgradnje. Daljnje povećanje koncentracije fotokatalizatora nema učinka na aktivnost fotokatalizatora zbog povećanja mutnoće suspenzije jer dolazi do smanjenja transmisije svjetlosti što ima negativan učinak na razgradnju bojila.

Abstract (english)

Wastewaters are an ecological issue because of different organic compounds whose presence is not wanted. Before discharging them into the effluent they must be treated properly with different methods and processes, such as mechanical removal of impurities, physical, biological and chemical methods. Advanced oxidation processes (AOP) are one of the possibilities for wastewater treatment. Among them is photocatalysis, which involves catalyzed pollutant decomposition under the influence of solar irradiation. Since TiO2 has limited efficiency under visible light due to large band gap, composite photocatalysts of conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and TiO2 with oxidant FeCl3 were synthesized by chemical oxidative polymerization. Composites had different PEDOT:TiO2 ratios as they were synthesized with the ratio of EDOT monomer and TiO2 nanoparticles 1:2, 1:3, 1:4, 1:5, 1:10 and 1:20. Composite photocatalysts were characterized by FTIR spectroscopy and UV/Vis spectroscopy. The photocatalytic efficiency of the synthesized nanocomposite photocatalysts was examined by monitoring the removal of Acid Blue 25 (AB25) dye under the simulated solar irradiation. During the photocatalysis process the discoloration was monitored by measuring the absorbance with UV/VIS spectrophotometer, while the mineralization process was monitored by measuring the total organic carbon (TOC). The results of the experiment showed that an increase of the concentration of the catalyst increases the efficiency of the photocatalysis and the apparent first-order rate constant. Further increase of the photocatalysts concentration does not have an effect on the photocatalyst activity since the turbidity increases which results in the reduction of light transmission that has a negative effect on the dye decomposition.

• Keywords: fotokataliza; napredni oksidacijski procesi; poli(3 4-etilendioksitiofen); titanijev dioksid; Acid Blue 25
• Keywords (english): photocatalysis; advanced oxidation processes; poly(3 4-ethylenedioxythiophene); titanium dioxide; Acid Blue 25
• Language: croatian
• URN:NBN: urn:nbn:hr:149:543198
• Study programme: Title: Chemical Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-03-18 13:10:52