Fotokatalitička učinkovitost BiVO4 pripremljenog hidrotermalnom i sol-gel metodom

undergraduate thesis

• Title (english): Photocatalytic efficiency of BiVO4 obtained by hydrothermal and sol-gel methods
• Author: Karla Krmek
• Mentor: Marin Kovačić (mentor)
• Committee member: Marin Kovačić (predsjednik povjerenstva)
• Committee member: Hrvoje Kušić (član povjerenstva)
• Committee member: Ana Vrsalović Presečki (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Uslijed sve veće proizvodnje i terapeutske primjene farmaceutika, otpadne vode onečišćene su farmaceuticima poput diklofenaka (DCF) te predstavljaju značajan ekološki problem. Farmaceutici spadaju u grupu mikroonečišćivala, čija se sve veća prisutnost primjećuje u površinskim i podzemnim vodama. Glavni izvor krije se u nedovoljnoj učinkovitost konvencionalnih metoda obrade, zbog čega se u posljednje vrijeme sve veća pažnja pridaje naprednim oksidacijskim procesima kao obećavajućim metodama uklanjanja mikroonečišćivala. Jedan od takvih procesa je i fotokataliza, proces razgradnje onečišćujućih tvari pod utjecajem UV/VIS zračenja uz prisutnost fotokatalizatora na kojem dolazi do efekta adsorpcije tih tvari i njihove razgradnje uslijed djelovanja radikalskih vrsta. U ovom radu prikazan je postupak sinteze BiVO4 fotokatalizatora, jednog od novijih i sve više istraživanih fotokatalizatora. Zanimljiv je upravo zbog fotokatalitičke aktivnosti pod utjecajem vidljive svjetlosti. Fotokatalizator je sintetiziran hidrotermalnom i sol-gel metodom, pri čemu se sol-gel metoda pokazala neuspješnom. Termogravimetrijskom analizom hidrotermalnog BiVO4 ustanovljena je velika količina etilen glikola preostalog iz sinteze u uzorku. Učinkovitost uklanjanja diklofenaka DCF-a hidrotermalnim BiVO4 ispitana je u suspenziji pri pH 4, 6 i 8, pod simuliranim Sunčevim zračenjem, pri čemu je uklanjanje DCF-a praćeno tekućinskom kromatografijom visoke djelotvornosti. Nakon 60 min fotokatalitičke obrade pri pH 4 uklonjeno je 31,67 % DCF-a, dok pri pH 4 i pH 8 tek 12,32 %, odnosno 3,12 % DCF-a. Uklanjanje DCF-a moglo se opisati gotovo podjednako dobro kinetičkim modelom 1. i 2. reda na temelju ocjenjivanja koeficijenta regresije. U daljnjim istraživanjima potrebno je poboljšati čistoću dobivenog BiVO4.

Abstract (english)

Due to the increasing production and therapeutic use of pharmaceuticals, wastewater is contaminated by pharmaceuticals, such as diclofenac (DCF), and represents a significant environmental problem. Pharmaceuticals belong to the group of micropollutants, whose increasing presence is observed in surface and groundwater. The main source lies in the lack of efficiency of conventional treatment methods, which is why more and more attention has been recently given to advanced oxidation processes as promising methods for the removal of micropollutants. Amongst them is photocatalysis, a process for the degradation of pollutants under the influence of UV/VIS irradiation in the presence of a photocatalyst on which adsorption of these substances occurs and subsequent degradation by radical species. This work describes the synthesis process of BiVO4 photocatalysts, one of the more recent and increasingly studied photocatalysts. It is interesting because of photocatalytic activity under the influence of visible light. The photocatalyst was synthesized by hydrothermal and sol-gel methods. The sol-gel method was unsuccessful. Hydrothermal BiVO4 was analysed by thermogravimetric analysis, which revealed a large quantity of residual ethylene glycol within the sample. The efficiency (DCF) in water under simulated solar irradiation, samples were analyzed by high performance chromatograph. Removal efficiency was tested in suspension at pH values of 4, 6 and 8. At pH 4 the removal of DCF equaled 31.67%, whereas at pH 6 and 8 the removal was 12.32 % and 3.12 % respectively. The removal of DCF could be almost equally well fitted to 1st and 2nd order kinetic models, on the basis of regression coefficients. In further research, it is necessary to improve the purity of the obtained BiVO4.

• Keywords: BiVO4; fotokataliza; hidrotermalna sinteza; sol-gel sinteza; uklanjanje mikroonečišćivala
• Keywords (english): BiVO4; photocatalysis; hydrothermal synthesis; sol-gel synthesis; removal of micropollutants
• Language: croatian
• URN:NBN: urn:nbn:hr:149:946383
• Project: Number: IP-2018-01-1982; Title: Nano-katalizatori aktivirani Sunčevim zračenjem u tehnologijama zaštite okoliša; Title: Nano-sized solar-active catalysts for environmental technologies; Acronym: NaSCEnT; Leader: Hrvoje Kušić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Environmental Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-05-24 12:24:19