Optimiranje fotokatalitičke razgradnje neonikotinoida u uvjetima UVA-LED zračenja

master's thesis

• Title (english): Optimization of photocatalytic degradation of neonicotinoids under UVA-LED irradiation
• Author: Kristina Liber
• Mentor: Vesna Tomašić (mentor)
• Committee member: Vesna Tomašić (predsjednik povjerenstva)
• Committee member: Marina Duplančić (član povjerenstva)
• Committee member: Domagoj Vrsaljko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Pesticidi su proizvodi kemijskog ili biološkog porijekla namijenjeni suzbijanju štetnika u poljoprivredi. Unatoč brojnim prednostima, pesticidi jednostavno dospijevaju u tlo i površinske i podzemne vode te mogu biti iznimno opasni za ekosustav i zdravlje živih organizama. S obzirom da ih je teško ukloniti iz voda konvencionalnim tehnikama obrade, prednost se daje naprednim oksidacijskim procesima s naglaskom na heterogenu fotokatalizu. U teorijskom dijelu rada dan je uvid u problematiku s posebnim naglaskom na heterogenu fotokatalizu, razvoj fotokatalizatora učinkovitih u uvjetima simuliranog Sunčevog zračenja te pregled uobičajenih izvedbi fotoreaktora. Cilj rada bio je ispitati utjecaj intenziteta zračenja, pH vrijednosti te koncentracije otopine imidakloprida na fotokatalitičku aktivnost imobiliziranog TiO2 katalizatora, primjenom imidakloprida kao modelne komponente. Mjerenja su provedena u pločastom fotoreaktoru uz recirkulaciju reakcijske smjese te uz UVA-LED module kao izvore zračenja (20 i 30 W) smještene izvan reaktora. Prije i nakon svakog eksperimenta mjeren je pH i ukupni organski ugljik (engl. Total organic carbon, TOC), a fotokatalitička razgradnja praćena je mjerenjem promjene koncentracije imidakloprida primjenom tekućinske kromatografije visoke djelotvornosti (engl. High performance liquid chromatography, HPLC). Istraživanja su provedena prema planu eksperimenta izrađenom pomoću programskog paketa Design-Expert. Nađeno je da je intenzitet zračenja jedini signifikantni (utjecajni) faktor za fotokatalitičku razgradnju imidakloprida. Provedena je kinetička anliza, predložen je odgovarajući kinetički model te je postignuto vrlo dobro slaganje između eksperimentalnih rezultata i pretpostavljenog modela reakcije. Proveden je eksperiment pri optimalnim uvjetima rada bez prethodne obrade reakcijske smjese u ultrazvučnoj kupelji, koji je pokazao neznatno manju fotokatalitičku učinkovitost u odnosu na fotokatalizu uz prethodnu primjenu ultrazvuka. Eksperiment sa optimalnim radnim uvjetima proveden je i pri izvoru zračenja UVA-LED od 20 W, pri čemu je postignuta dvostruko manja fotokatalitička aktivnost u odnosu na UVA-LED snage 30 W. Fotolitička razgradnja imidakloprida pokazala je vrlo malu učinkovitost, a nađeno je i da aeracija ne pogoduje razgradnji imidakloprida.

Abstract (english)

Pesticides are products of chemical or biological origin intended for pest control in agriculture. Despite all the advantages they have when they used in agriculture, pesticides easily reach the soil and surface and groundwater and can be extremely dangerous to the ecosystem and the health of living organisms. Since they are difficult to remove from water by conventional treatment techniques, advanced oxidation processes with an emphasis on heterogeneous photocatalysis are preferred. The theoretical part provides an insight into the issue with special emphasis on heterogeneous photocatalysis, the development of photocatalysts effective under simulated Solar irradiation and an overview of common photoreactor designs. In this work, the aim was to investigate the influence of irradiation intensity, pH value and concentration of imidacloprid solutions on the photocatalytic activity on immobilized TiO2 catalyst using a pesticide imidacloprid. All measurements were performed in a plate flat photoreactor with recirculation of the reaction mixture and a source of UVA-LED (20 i 30 W) irradiation located outside of the reactor. Before and after each experiment, pH and Total organic carbon (TOC) were measured, and photocatalytic degradation was monitored by measuring the change of imidacloprid concentration using High performance liquid chromatography (HPLC). An experiment plan was made by using the Design-Expert software package. It was shown that only the irradiation intensity affects on degradation of imidacloprid. A kinetic analysis was performed, an appropriate kinetic model was suggested, and a very good agreement was reached between the experimental results and the assumed reaction model. An experiment with optimal parameters without pre-treatment of reaction mixture was performed in an ultrasonic bath, which shows slightly lower photocatalytic efficiency compared to photocatalysis with ultrasound. The experiment with optimal parameters was also performed under 20 W UVA-LED irradiation source with almost twice less photocatalytic activity compared to 30 W UVA-LED. The photolysis reaction showed very low degradation efficiency while aeration did not affect on degradation of imidacloprid.

• Keywords: pesticidi; heterogena fotokataliza; imidakloprid; TiO2; pločasti fotoreaktor
• Keywords (english): pesticides; heterogeneous photocatalysis; imidacloprid; TiO2; plate flat photoreactor
• Language: croatian
• URN:NBN: urn:nbn:hr:149:085735
• Project: Number: IP-2018-01-8669; Title: Intenzifikacija fotokatalitičkih i katalitičkih procesa za obradu otpadnih voda i otpadnih plinova; Acronym: IN-PhotoCat; Leader: Vesna Tomašić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Environmental Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka ekoinženjerstva (magistar/magistra inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-04-07 08:37:25