Adsorpcija fenitoina in oksitetraciklina na nanodelce ZnO

Kermelj, Vid (author), Lavrenčič Štangar, Urška (mentor)

S povečevanjem količine farmacevtikov v odpadnih vodah so se pojavile skrbi zaradi vplivov na okolje. Ker se je klasično biološko čiščenje izkazalo kot neuspešno za njihovo odstranjevanje, so se raziskave osredotočile na sklopitev biološkega čiščenja z naprednimi oksidacijskimi metodami, med katere spada tudi fotokatalitska razgradnja. Eden od procesov, ki fotorazgradnjo spremlja, je adsorpcija. Z namenom boljšega vpogleda v fotodegradacijo sem se v svoji diplomi osredotočil na razumevanje procesa adsorpcije. Za adsorbata sem izbral fenitoin in oksitetraciklin, ki se v odpadnih vodah pogosto pojavljata v relativno visokih količinah in hkrati nista zelo raziskana. Kot fotokatalizator sem raziskoval nanodelce ZnO, ki kažejo obete zaradi primerne energije prepovedanega pasu in relativno majhne škodljivosti za okolje. Diplomsko delo obsega karakterizacijo ZnO, študij kinetike in termodinamike adsorpcije obeh farmacevtikov na ZnO ter računalniške simulacije elektronske gostote po površini molekul. Ugotovil sem, da so v suspenziji nanodelci prisotni v obliki poroznih 500 nm aglomeratov z nekoliko pozitivno nabito površino. Adsorpcija obeh farmacevtikov spada v fizisorpcijo, ki je verjetno osnovana na elektrostatskih interakcijah. Ugotovil sem, da je adsorpcija na površino aglomeratov zelo hiter proces, medtem ko je difuzija in adsorpcija v pore veliko počasnejša. Fenitoin se adsorbira le na površino aglomeratov, medtem ko oksitetraciklin lahko vstopa tudi v pore ZnO.

• Language: Slovenian
• Keywords: adsorpcija, ZnO, fenitoin, oksitetraciklin
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2021
• PID: 20.500.12556/RUL-129746
• COBISS.SI-ID: 79572995
• Publication date in RUL: 07.09.2021

Secondary language

• Language: English
• Title: Phenytoin and oxytetracycline adsorption on ZnO nanoparticles

Abstract

With the increase in the amount of pharmaceuticals in wastewater, concerns have arisen about the impact on the environment. As traditional biological treatment proves unsuccessful for their removal, research has focused on combining biological treatment with advanced oxidation methods, including photocatalytic degradation. One of the processes that accompanies photodegradation is adsorption. To gain better insight into photodegradation, the research was focused on understanding the adsorption process. Phenytoin and oxytetracycline were chosen as adsorbates because they are found in relatively high amounts in wastewater and at the same time are not very well researched. ZnO nanoparticles were explored as photocatalyst as they are promising due to sufficient band gap energy and relatively low environmental toxicity. The work was based on the experiments on the characterization of ZnO, the study of the kinetics and thermodynamics of adsorption of both pharmaceuticals on ZnO, and computer simulations of the electron surface potential of molecules. It was found that the nanoparticles in suspension are in the form of porous 500 nm agglomerates with a slightly positively charged surface. The adsorption of the two pharmaceuticals belongs to physisorption, which is probably due to electrostatic interactions. It was found that adsorption on the surface of the agglomerates is a very fast process, while diffusion and adsorption into the pores are much slower. Phenytoin is adsorbed only on the surface of the agglomerates, while oxytetracycline can also penetrate into the pores of ZnO.

• Keywords: adsorption, ZnO, phenytoin, oxytetracycline