Recikliranje odpadne pet embalaže s pod- in nadkritično vodo

diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje

Anita Sever (Author), Mojca Škerget (Mentor), Maja Čolnik (Co-mentor)

Abstract

Polietilen tereftalat (PET) sodi med najbolj razširjene termoplastične smole. Ima dobre mehanske, toplotne in kemijske lastnosti. Uporabljamo ga predvsem za izdelavo embalaže za pitno vodo in živila. PET je nerazgradljiva plastika, zato se ga vedno več nabira v naravi. Zaradi negativnih posledic kopičenja PET v naravi, dajemo dandanes vse večji pomen ločevanju in recikliranju odpadne PET embalaže. PET lahko recikliramo na več načinov. Eden izmed najučinkovitejših načinov je kemijsko recikliranje s hidrotermično degradacijo. Namen diplomskega dela je bil preučiti recikliranje odpadne PET embalaže s pod in nadkritično vodo. Pod- in nadkritična voda je odličen reakcijski medij za degradacijo odpadne PET embalaže. Odpadna PET embalaža namreč po degradaciji v pod in nadkritičnih vodi razpade na monomere. Glaven monomer, ki nastane je tereftalna kislina (TPA). TPA predstavlja glavno korist recikliranja, iz nje namreč lahko ponovno izdelamo PET. Eksperimentalni del hidrotermične degradacije odpadne PET embalaže smo izvajali v visokotlačnem in visokotemperaturnem šaržnem reaktorju v pod in nadkritični vodi. Reakcije smo izvajali pri štirih različnih temperaturah 250, 300, 350 in 400 °C in reakcijskem času 1, 10 in 30 minut. Nastale produkte hidrotermične degradacije smo analizirali s HPLC, FT-IR in GC-MS metodami. Analize produktov hidrotermične degradacije odpadne PET embalaže so pokazale, da dobimo najvišji izkoristek glavnega produkta TPA pri podkritičnih pogojih, in sicer pri temperaturi 300 °C in času 30 minut. Izkoristek TPA pri degradaciji odpadne barvne PET embalaže je znašal 85%. Za primerjavo izkoristkov smo izvedli še hidrotermično degradacijo brezbarvne odpadne PET embalaže pri enakih pogojih. Dobljen izkoristek je znašal 90%. Z višanjem temperature v nadkritično območje se je izkoristek TPA zniževal, zaradi nastajanja sekundarnih produktov.

Keywords

PET;kemijsko recikliranje;pod in nadkritična voda;hidrotermična degradacija;tereftalna kislina;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2019
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[A. Sever]
UDC:	678.742.2.028.6:54-139(043.2)
COBISS:	22608406
Views:	981
Downloads:	0
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Recycling of pet waste using sub- and supercritical water
Secondary abstract:	Polyethylene terephthalate (PET) is one of the most widely used types of plastic resins. It has good mechanical, thermal and chemical properties. We use it primarily for the production of packaging for drinking water and food. PET is non-degradable plastic, which is why it has accumulated so much in the nature. Because of the negative consequences of the accumulation of PET in the nature, it is highly important to recycle PET packaging waste. PET can be recycled in several ways. One of the most effective solution is chemical recycling with hydrothermal degradation. The purpose of the diploma thesis was to examine the recycling of PET packaging waste with sub- and supercritical water. Sub- and supercritical water is an excellent reaction medium for the degradation of PET packaging waste, that can be decomposed into monomers. The main monomer that is produced is terephthalic acid (TPA). TPA is considered to be the main benefit of recycling because it is the compound that can be used fort the synthesis of PET again. The experimental part of the hydrothermal degradation of PET packaging waste was carried out in the high-pressure and high-temperature batch reactor in the sub- and supercritical water. Reactions were carried out at four different temperatures of 250, 300, 350 and 400 °C, and the reaction time was 1, 10 and 30 minutes. The resulting hydrothermal degradation products were analyzed by HPLC, FT-IR and GC-MS methods. The analysis of products of hydrothermal degradation of PET packaging waste showed that the highest yield of the main TPA product was obtained under subcritical conditions at a temperature of 300 °C and 30 minutes of reaction time. The yield of TPA obtained by degradation of coloured PET packaging waste was 85%. For comparison, hydrothermal degradation was carried out under the same conditions using colourless PET packaging waste. The obtained yield of TPA was 90%. By increasing the temperature to the supercritical area, the TPA yield decreased due to the formation of secondary products.
Secondary keywords:	PET;chemical recycling;sub and supercritical water;hydrothermal degradation;terephthalic acid;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Embargo end date (OpenAIRE):	2020-12-30
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	VIII, 24 str.
ID:	11164855