Razgradnja organskih onečišćivala peroctenom kiselinom

master's thesis

• Title (english): Degradation of organic pollutants with peracetic acid
• Author: Lucija Tarle
• Mentor: Marin Kovačić (mentor)
• Committee member: Marin Kovačić (predsjednik povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Committee member: Irena Ivanišević (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-24, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

U današnje vrijeme jedan od glavnih problema je onečišćenje i narušavanje prirodnog okoliša nastalim onečišćivalima, to jest tvarima različitog podrijetla i struktura s poznatim i/ili potencijalnim ekotoksičnim učincima. Stoga je jedan od glavnih načina sprječavanja zagađenja vode, njihovo učinkovito pročišćavanje prije njihovog ispuštanja. U novije vrijeme napredni oksidacijski procesi (engl. advanced oxidation process, AOP) predstavljaju alternativu konvencionalnim procesima obrade otpadnih voda. Njihova glavna prednost je brza i djelotvorna razgradnja organskih onečišćivala do vode i ugljičnog dioksida. U otpadnim vodama, među različitim organskim onečišćivalima, fenoli se smatraju prioritetnim onečišćivalima.U ovome radu provedena je razgradnja fenola peroctenom kiselinom u lužnatim i kiselim uvjetima. Uočeno je da blago lužnati uvjeti odgovaraju za oksidaciju fenola uz PAA, pri čemu je konačna konverzija 8,5 % dok do oksidacije fenola u kiselom mediju nije došlo.Stoga kako bi došlo do deprotonacije prijelaznog kompleksa potrebni su lužnati uvjeti. Također,oksidacijom fenola djelovanjem PAA može se očekivati kako dolazi do nastanka produkata 1,2-dihidroksibenzena (katehol) te 1,4-dihidroksibenzena (hidrokinon), ovisno o mjestu oksidacije aromatskog prstena, te octene kiseline kao rezultat redukcije PAA. S ciljem identifikacije razgradnih produkata korištena je tekućinska kromatografija spregnuta s masenom spektrometrijom uz elektrosprej ionizaciju. Za ionizaciju odabran je negativan potencijal kako bi se formirali deprotonirani molekulski ioni u oblaku.Na temelju dobivenih podataka može se zaključiti da kako je za učinkovitu oksidaciju fenola uz PAA potrebna velika količina PAA, što čini potencijalnu primjenjivost PAA u svrhu razgradnje organskih onečišćivala vrlo ograničenom. Zaključno, obzirom na cijenu PAA, drugi napredni oksidacijski procesi su pogodniji za njegovu razgradnju.

Abstract (english)

Nowadays, one of the main problems is the pollution and disturbance of the natural environment by the resulting pollutants, ie substances of different origins and structures with known and / or potential ecotoxic effects. Therefore, one of the main ways to prevent water pollution is to effectively purify them before they are discharged. In recent times, advanced oxidation processes (AOP) are an alternative to conventional wastewater treatment processes. Their main advantage is the rapid and efficient decomposition of organic pollutants to water and carbon dioxide. In wastewater, among various organic pollutants, phenols are considered as priority pollutants. In this work, the decomposition of phenols by peracetic acid under alkaline and acidic conditions was carried out. It was observed that slightly alkaline conditions are suitable for the oxidation of phenol with PAA, where the final conversion is 8.5% until the oxidation of phenol in an acidic medium did not occur. Therefore, alkaline conditions are required to deprotonate the transition complex. Also, oxidation of phenol by the action of PAA can be expected to result in the formation of
1,2-dihydroxybenzene (catechol) and 1,4-dihydroxybenzene (hydroquinone) products, depending on the site of oxidation of the aromatic ring, and acetic acid as a result of PAA reduction. In order to identify the degradation products, liquid chromatography coupled to mass spectrometry with electrospray ionization was used. Negative potential was selected for ionization to form deprotonated molecular ions in the cloud. Based on the obtained data, it can be concluded that efficient oxidation of phenols with PAA requires a large amount of PAA, which makes the potential applicability of PAA for decomposition of organic pollutants very limited. In conclusion, given the cost of PAA, other advanced oxidation processes are more suitable for its degradation.

• Keywords: obrada voda; organska onečišćivala; peroctena kiselina; razgradnja
• Keywords (english): degradation; organic pollutants; peracetic acid; water treatment
• Language: croatian
• URN:NBN: urn:nbn:hr:149:524141
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-04-17 12:33:16