Laserska sinteza dvokomponentnih nanočestica u tekućinama za primjene u fotokatalizi

master's thesis

• Title (english): Laser synthesis of two-component nanoparticles in liquids and applications in photocatalysis
• Author: Nikola Klobučar
• Mentor: Nikša Krstulović (mentor)
• Mentor: Ivan Kokanović (komentor)
• Committee member: Nikša Krstulović (predsjednik povjerenstva)
• Committee member: Ivan Kokanović (član povjerenstva)
• Committee member: Maja Planinić (član povjerenstva)
• Committee member: Željko Skoko (član povjerenstva)
• Committee member: Damir Aumiler (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2020-07-08, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U ovom radu smo proučavali stopu degradacije organskih boja pomoću nanočestica cinkovog oksida (ZnO) primjenom fotokatalize. Ovo istraživanje je potaknuto da se pronađe ekološki prihvatljiv način za degradaciju industrijskih organskih boja izbačene u prirodu preko otpadnih voda. Cinkov oksid je biološki i ekološki neinvazivni materijal s relativno brzim vremenom raspada i time je jedan od najboljih kandidata kao katalizator raspada industrijskih boja. Ideja je da bi nanočestice ispuštene u otpadne vode potpomogle fotokatalizi u raspadanju industrijskih boja putem UV zraka Sunca. ZnO nanočestice sintetizirali smo metodom laserske ablacije u tekućini. Dobivene koloidne otopine analizirali smo pomoću spektrofotometra kako bi dobili ovisnosti apsorbancije o valnim duljinama. Pomoću dobivene ovisnosti napravili smo Taucov graf iz kojeg smo izračunali energetski procijep između vodljive i valentne vrpce cinkovog oksida. Dobivene uzorke nanočestica proučavali smo i pomoću skenirajućeg elektronskog mikroskopa (SEM) da odredimo njihov oblik, promjer, morfologiju i raspodjelu po veličinama. Da bismo izračunali brojčanu i masenu koncentraciju nanočestica u pojedinim uzorcima, uzeli smo metu korištenu za lasersku ablaciju i pomoću svjetlosnog mikroskopa izračunali volumene kratera nastalih nakon laserske ablacije. Volumen kratera smo izračunali tako da smo odredili kružne površine kratera na različitim dubinama, izračunali volumene krnjih stožaca gdje su baze tih stožaca bile površine kratera i zbrojili volumene krnjih stožaca da dobijemo konačan volumen kratera. Volumen kratera odgovara volumenu ablatiranog materijala odnosno ukupnom volumenu nanočestica iz kojeg možemo odrediti i njihovu ukupnu masu u koloidnoj otopini. Kolodine otopine ZnO nanočestica smo podijelili u uzorke različitih brojčanih koncentracija i dodali industijske boje u pojedine uzorke. Te uzorke smo potom ponovno analizirali spektrofotometrom dobivajući ovisnost apsorbacije o valnim duljinama. Nakon toga, uzorke smo tretirali UV&VIS živinom lampom svakih 10 minuta između kojeg smo svaki put napravili spektrofotometriju.

Abstract (english)

In this paper, we investigated the rate of degradation of organic dyes across zinc oxide (ZnO) nanoparticles using photocatalysis. This research has shown that there is an environmentally friendly way to decompose industrial organic dyes released into the environment through wastewater. Zinc oxide is a biologically and environmentally friendly non-invasive material with relatively fast decay time, and it being one of the best choices as a catalyst for decay of industrial paints. The idea is that nanoparticles discharged into wastewater would assist photocatalysts in the decay of industrial dyes through the natural UV rays. ZnO nanoparticles were synthesized by laser ablation in the liquid. The resulting colloidal solutions were analyzed by us using spectrophotometers to obtain the wavelength dependences of absorbance. With the help of dependency, we made a Tauc graph from which we calculated the energy gap between water and valence bands of zinc oxide. We studied the obtained nanoparticle samples and used a scanning electron microscope (SEM) to determine their shape, diameter, morphology and size distributions. In order to calculate the number and increase the concentration of nanoparticles in individual samples, we used laser ablation and, using light microscopes, calculated the volumes of craters formed after. We calculated the volume of the crater by determining the circular surfaces of the crater at different depths, calculating the volumes of the truncated cones where the bases of these cones were the surfaces of the crater, and summing the volumes of the truncated cones to obtain the final volume of the crater. The volume of the crater corresponds to the volume of ablated material, that is, the total volume of nanoparticles from which the destination is determined, and which is the total mass in the colloidal solution. The wells of the ZnO nanoparticle solution were partitioned into samples of different numerical concentrations and added industrial dyes to the individual samples. These samples were re-analyzed with a spectrophotometer to obtain a greater dependence of the wavelength absorption. Subsequently, the samples were treated with UV and VIS mercury lamps every 10 minutes between which we performed spectrophotometry each time.

• Keywords: dvokomponentne nanočestice; nanočestice cinkovog oksida; fotokataliza
• Language: croatian
• URN:NBN: urn:nbn:hr:217:406856
• Study programme: Title: Physics; specializations in: Education; Course: Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije fizike (magistar/magistra edukacije fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-02-01 12:27:42