Utjecaj elektromagnetskog zračenja na starenje mikroplastike

master's thesis

• Title (english): Influence of electromagnetic radiation on microplastic aging
• Author: Helena Sudarić
• Mentor: Lidija Furač (mentor)
• Committee member: Lidija Furač (predsjednik povjerenstva)
• Committee member: Matija Cvetnić (član povjerenstva)
• Committee member: Dajana Kučić Grgić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-22, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Zahvaljujući dobrim karakteristikama i niskoj cijeni, proizvodnja plastičnih proizvoda u posljednjih nekoliko desetljeća znatno je porasla. Većina tih proizvoda namijenjena je jednokratnoj upotrebi što dovodi do stvaranja velike količine otpada koji često nije dobro zbrinut te završava u okolišu. Djelovanjem prirodnih pojava na plastične proizvode, oni gube svoja svojstva i razgradnjom prelaze u oblik mikroplastike. Plastične čestice takve veličine mogu se pronaći u ribama koje poslije konzumiraju ljudi te u podzemnim vodama. U ovom radu ispitani su napredni oksidacijski procesi, UV-C/H2O2, UV-C/S2O82-, Fenton i foto-Fenton procesi, kao metode uklanjanja mikroplastike polietilena (PE) i polipropilena (PP). Prilikom razgradnje pratio se utjecaj koncentracije oksidansa (H2O2 i Na2S2O8), mase mikroplastike, pH vrijednost i duljine izlaganja UV-C svijetlu na raspad navedenih polimera. Foto-Fenton procesi provodili su se na sličan način, ali uz praćenje utjecaja H2O2 pratio se i utjecaj koncentracije Fe2+ iona dok se duljina izlaganja zračenju i masa mikroplastike nisu mijenjale. Fenton proces provodio se kao foto-Fenton proces, ali bez izlaganja UV-C zračenju. Nakon provedbe UV-C/H2O2 i UV-C/S2O82- naprednih oksidacijskih procesa i analize dobivenih rezultata, kao bolji oksidans pokazao se Na2S2O8 jer je i kod PP i PE mikroplastike njegovom primjenom došlo do većeg stupnja razgradnje. Također, maksimalna razgradnja postignuta je pri maksimalnom vremenu izlaganja zračenju (90 min) uz minimalnu koncentraciju oksidansa (1 mM) te obrnuto, pri minimalnom vremenu izlaganja (30 min) i maksimalnoj koncentracije (20 mM) radi prisutnosti „Scavenger effecta“. Usporedbom dobivenih rezultata nakon provedenih Fenton i foto-Fenton procesa, foto-Fenton proces u većini slučajeva pokazao se učinkovitijim jer UV-C zračenje doprinosi nastanku većeg broja radikala.

Abstract (english)

Due to its good characteristics and low price, the production of plastic materials has increased significantly in the last few decades. The vast majority of these materials are made for single use only, which leads to large amounts of waste. Unfortunately, most of the plastic waste is not disposed of in the right way so it ends up in the environment where it starts to disintegrate, lose its properties and break down into smaller pieces called microplastic. These tiny particles can be found in fish and underground water. In this thesis advanced oxidation, UV-C/H2O2, UV-C/S2O82-, Fenton and photo-Fenton processes are discussed as the methods of polyethylene and polypropylene microplastic removal. During decomposition of these polymers by advanced oxidation processes, the influence of oxidant concentration (H2O2 and Na2S2O8), the mass of microplastic, pH value and time of exposure to UV-C light was monitored. Photo-Fenton process was performed similarly, but in addition to monitoring the effect of H2O2, the effect of Fe2+ ion concentration was also monitored while the length of radiation exposure and mass of microplastic did not change. The Fenton process was carried out as a photo-Fenton process but without exposure to UV-C radiation. After the implementation of UV-C/H2O2 and UV-C/S2O82- advanced oxidation processes and the analysis of the obtained results, Na2S2O8 proved to be a better oxidant. proved to be a better oxidant as a higher degree of decomposition in both types of plastic polymers occurred. Also, the maximum decomposition was achieved at the maximum exposure time to radiation (90 min) with a minimum concentration of oxidant (1 mM) and vice versa, at a minimum exposure time (30 min) and maximum concentration (20 mM) due to the presence of the „Scavenger effect“. Comparing the results obtained after the Fenton and photo-Fenton processes, the photo-Fenton process in most cases proved to be more efficient, which was to be expected because UV-C radiation contributes to the formation of more radicals.

• Keywords: polipropilen; polietilen; napredni oksidacijski procesi; UV-C/H2O2; UV-C/S2O82-; Fenton procesi; foto-Fenton procesi
• Keywords (english): polypropylene; polyethylene; advanced oxidation processes; UV-C/H2O2; UV-C/S2O82-; Fenton process; photo-Fenton process
• Language: croatian
• URN:NBN: urn:nbn:hr:149:215082
• Project: Number: IP-2019-04-9661; Title: Primjena naprednih tehnologija obrade voda za uklanjanje mikroplastike; Title: Advanced Water Treatment Technologies for Microplastics Removal; Acronym: AdWaTMiR; Leader: Tomislav Bolanča; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-04-14 11:45:22