Photocatalytic treatment of pharmaceutical contaminated water with multicomponent photocatalysts active under solar irradiation

Onečišćenja voda farmaceuticima te nemogućnosti njihovog uklanjanja tradicionalnim metodama obrade vode, potakla je istraživanje naprednih oksidacijskih procesa, kao rješenja za navedenu problematiku. Ideja naprednih metoda jest stvaranje reaktivnih radikala koji će razgraditi postojanu organsku tvar. U svrhu boljeg razumijevanja procesa fotokatalize i čimbenika koji na nju utječu, izrađene su mnogobrojne studije, no proces i dalje nije u potpunosti implementiran u industrijska postrojenja, zbog čega postoji potreba za daljnjim unaprjeđivanjem i razvojem. Cilj ovog rada je istražiti fotokatalitičku razgradnju amoksicilina korištenjem imobiliziranih slojeva hematita (α-Fe2O3) i titanijeva dioksida (TiO2), zasebno i u kombinaciji te koristeći oksidanse, vodikov peroksid (H2O2) i natrijev persulfat (Na2S2O8). Proveden je set eksperimenata pod simuliranim Sunčevim zračenjem u trajanju od 90 minuta, a svakih 15 minuta praćena je konverzija amoksicilina tekućinskom kromatografijom visoke djelotvornosti. Najveće uklanjanje ostvareno je s kombiniranim fotokatalizatorom, odnosno Fe2O3-TiO2, u prisutnosti S₂O82-, pri čemu je uklanjanje iznosilo više od 95%. Uklanjanje u najmanjoj mjeri zabilježeno je s hematitom, a oksidansi nisu značajnije poboljšali uklanjanje amoksicilina.Water pollution by pharmaceuticals and the inability of conventional wastewater treatment processes has initiated research on the topic of advanced oxidation. The main aim of these methods is to induce the creation of reactive radicals, which will readily degrade organic compounds. Even though many studies have been made and the process is very well studied, complete implementation of these methods to fruition is not yet widely achieved. Therefore further development and research is vital. Within this study photocatalytic degradation of amoxicillin, using immobilized hematite (α-Fe2O3) and titanium dioxide (TiO2), separately and combined. For the improval of the degradation rate, two oxidants were used, hydrogen peroxide (H2O2) and sodium persulfate (Na2S2O8). A set of experiments was carried out under simulated solar irradiation up to 90 minutes and every 15 minutes an aliquot was taken out of the reaction in order to determine the extent of removal by high performance liquid chromatography. The most efficient photocatalyst for the degradation of amoxicillin was the Fe2O3-TiO2 photocatalyst in the presence of S₂O82-, in which the achieved degradation rate was higher than 95%. Hematite alone has achieved the lowest degradation extent overall, with or without the presence of an oxidant