Application of TiO2-Fe2O3 photocatalyst for degradation of pharmaceuticals

Farmaceutici su spojevi koji se koriste za liječenje i sprečavanje bolesti, stoga imaju veliku ulogu u životu ljudi i životinja. Ukoliko u prekomjernim količinama dospiju u okoliš, narušavaju prirodnu ravnotežu. Stoga se danas provodi velik broj istraživanja koja se odnose na uklanjanje farmaceutika iz okoliša, kako ne bi došlo do trajno štetnih posljedica. Diklofenak je nesteroidni antireumatik koji djeluje analgetski, protuupalno i antipiretski. Samim time njegova je upotreba široko rasprostranjena i zbog toga se nalazi u velikim količinama u okolišu. Cilj ovog istraživanja je ispitati učinkovitost razgradnje diklofenaka djelovanjem simuliranog Sunčevog zračenja. Kao fotokatalizator korišten je kompozit TiO2-Fe2O3 koji je sintetiziran na dva načina: sol-gel postupkom te koprecipitacijom. Fotokatalizator je nanošen na staklene pločice koje su služile kao nosači. Koprecipitacija kao jedna od metoda sinteze fotokatalizatora nije se pokazala obećavajućom, dok kod fotokatalizatora dobivenog sol-gel postupkom dolazi do najbolje adsorpcije DCF-a pri pH vrijednosti 4 te njegove razgradnje djelovanjem simuliranog Sunčevog zračenja. Većinu adsorpcijskih izotermi najbolje opisuje Freundlichov model adsorpcije što upućuje na nehomogenost površine fotokatalizatora. Primijećeno je kako se kod pH vrijednosti 4 ukloni najviše DCF-a, što je povezano s najvećim dosegom adsorpcije samog farmaceutika na površinu fotokatalizatora.Pharmaceuticals are chemical compounds used to treat and prevent diseases and as such have a major role in the lives of humans and animals. They have many positive but negative effects as well. Pharmaceuticals may sometimes harm the health and the environment. If they get into the environment in excess, they disturb the natural balance. That is why scientists have started to explore removal processes of pharmaceuticals so that they do not damage the environment seriously. Diclofenac is a non-steroidal anti-rheumatic agent that acts analgesic, anti-inflammatory, and antipyretic, and its use is widely spread all over the world, and it is believed that it is also present in large quantities in the environment. Likewise, the aim of this study was to evaluate the possibilities of advanced oxidation processes, especially photooxidative degradation of diclofenac under the influence of simulated solar radiation. The TiO2-Fe2O3 composite was used as the photocatalyst, which is obtained in two ways: sol-gel process and coprecipitation and applied to glass supports. Coprecipitation as one of the synthesis methods has not been shown to be promising but the sol–gel produced photocatalyst shows the best adsorption of diclofenac and its degradation under a simulated solar radiation when pH value is 4. Most adsorption isotherms are best described by the Freundlich adsorption model, which indicates the inhomogeneity of the photocatalyst surface. It has been noticed that at pH 4, diclofenac is removed, which is related to the maximum adsorption reach of the drug itself to the photocatalyst surface