Odstranjevanje bisfenolov iz pitne in odpadne vode s fotokatalizo in hidrodinamsko kavitacijo

Pajk, Pia (avtor), Heath, Ester (mentor), Lavrenčič Štangar, Urška (komentor)

Potreba po čisti pitni vodi je vsako leto večja, zaloge pitne vode pa se manjšajo. Uporaba prečiščene odpadne vode v namakalnih sistemih ima najvišji delež med možnostmi ponovne uporabe, a to s seboj prinese številne izzive, saj je odpadna voda glavni vir onesnaževal, ki vzbujajo zaskrbljenost po vstopu v okolje. Nujno je potrebno poskrbeti za izboljšano odstranitev teh onesnaževal iz odpadnih vod in posledično preprečiti ali vsaj zmanjšati njihov vstop v okolje. Primer tovrstnih onesnaževal so na primer bisfenoli. S kvartarnim čiščenjem odpadne vode bi se na podlagi zakonodajne resolucije »Direktive o čiščenju komunalne odpadne vode« moralo iz odpadne vode odstraniti ≥80% onesnaževal, ki vzbujajo zaskrbljenost. Pri tem velik potencial kažejo napredni oksidacijski procesi in še posebej njihove kombinacije. V magistrskem delu smo spremljali odstranjevanje onesnaževal, ki vzbujajo zaskrbljenost, točneje bisfenola A in štirih njegovih nadomestkov (bisfenola AF, bisfenola F, tetrametil bisfenola F in bisfenola S) s kombinacijo dveh naprednih oksidacijskih procesov – fotokatalize in hidrodinamske kavitacije. Izvedli smo sedem različnih vrst testiranj odstranjevanja izbranih bisfenolov iz pitne (200 ng/L) in odpadne (1000 ng/L) vode: (a)adsorpcijo bisfenolov na fotokatalizator (TiO2) v temi, (b) fotokatalizo, (c) hidrodinamsko kavitacijo, (d) vzporedno delovanje fotokatalize in hidrodinamske kavitacije, (e)zaporedno delovanje hidrodinamske kavitacije in fotokatalize, (f)zaporedno delovanje hidrodinamske kavitacije in fotokatalize z dodatkom H2O2 in (g) obsevanje z UV svetlobo. V namen določitve uspešnosti odstranjevanja izbranih spojin tekom različnih postopkov čiščenja smo razvili, optimizirali in validirali analizni metodi za določanje izbranih bisfenolov v pitni in odpadni vodi. Metodi temeljita na ekstrakciji na trdno fazo in analizi s plinskim kromatografom, sklopljenim z masnim spektrometrom. Pri eksperimentih s pitno vodo smo ugotovili, da je stopnja odstranitve bisfenolov pri kombinaciji fotokatalize in hidrodinamske kavitacije višja kot pri sami fotokatalizi oziroma sami hidrodinamski kavitaciji. Najboljše izkoristke odstranjevanja izbranih spojin smo dobili pri zaporednem delovanju 15 min hidrodinamske kavitacije in 15 min fotokatalize, pri čemer je bil edini bisfenol, ki je dosegel želenih ≥ 80 % odstranitve, tetrametil bisfenol F. V odpadni vodi pod nobenimi testiranimi pogoji nismo dosegli ≥ 80 % odstranitve. S tem smo potrdili, da je odpadna voda bolj kompleksna matrika kot pitna voda, kar pomeni, da je nujno nadaljnje preučevanje in razvoj kombinacij naprednih oksidacijskih procesov za odstranjevanje bisfenolov iz odpadne vode.

• Jezik: Slovenski jezik
• Ključne besede: bisfenoli, pitna voda, odpadna voda, napredni oksidacijski procesi, SPE-GC-MS
• Vrsta gradiva: Magistrsko delo/naloga
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Leto izida: 2024
• PID: 20.500.12556/RUL-164032
• Datum objave v RUL: 16.10.2024

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Removal of bisphenols from drinking and wastewater using photocatalysis and hydrodynamic cavitation

Izvleček

The demand for clean drinking water is increasing each year, while freshwater supplies are diminishing. The use of treated wastewater for irrigation is the most prevalent reuse option but comes with significant challenges due to wastewater being a primary source of contaminants of emerging concern. It is crucial to improve the removal of these pollutants from wastewater and, consequently, prevent or at least reduce their entry into the environment. Bisphenols are a notable example of such pollutants. According to the legislative resolution of the Urban Wastewater Treatment Directive, quaternary wastewater treatment should remove ≥ 80% of contaminants of emerging concern and other micropollutants. Advanced oxidation processes, and particularly their combinations, show great potential in this regard. In this master's thesis, we monitored the removal of pollutants of concern, specifically bisphenol A and four of its substitutes (bisphenol AF, bisphenol F, tetramethylbisphenolF, and bisphenol S), using a combination of two advanced oxidation processes – photocatalysis and hydrodynamic cavitation. We conducted seven different types of tests for the removal of the selected bisphenols from drinking water (200 ng/L) and wastewater (1000 ng/L): (a) adsorption of bisphenols onto a photocatalyst (TiO2) in the dark, (b) photocatalysis, (c) hydrodynamic cavitation, (d) simultaneous photocatalysis and hydrodynamic cavitation, (e) hydrodynamic cavitation followed by photocatalysis, (f) hydrodynamic cavitation followed by photocatalysis with the addition of H2O2, and (g) UV radiation. To determine the effectiveness of removing selected compounds during various cleaning processes, we developed, optimized, and validated analytical methods for detecting specific bisphenols in drinking and wastewater. These methods are based on solid-phase extraction and analysis using gas chromatography coupled with mass spectrometry. In testing with drinking water, we found that the removal rate of bisphenols in experiments with a combination of photocatalysis and hydrodynamic cavitation was higher compared to either photocatalysis or hydrodynamic cavitation alone. The most effective treatment was found to be 15 min of hydrodynamic cavitation followed by 15 min of photocatalysis, though only tetramethyl bisphenol F achieved the desired removal of ≥ 80%. In wastewater, we found that none of the tests achieved ≥ 80% removal. This confirmed that wastewater is a more complex matrix than drinking water, indicating the need for further development of advanced oxidation process combinations for bisphenol removal from wastewater.

• Ključne besede: bisphenols, drinking water, wastewater, advanced oxidation processes, SPE-GC-MS