Photocatalytical treatment of pharmaceutical micropollutants under simulated solar irradiation

Porast ljudske populacije i globalni razvoj rezultiraju rastućom potrošnjom vode, a time i povećanjem količine otpadnih voda. Neadekvatno obrađene otpadne vode, dospijećem u prirodne prijamnike, pridonose onečišćenju vode. Posebno su zabrinjavajuća farmaceutska mikroonečišćivala detektirana u vodama diljem svijeta, za čije uklanjanje nisu dostatni konvencionalni postupci obrade voda. Nesteroidni protupalni lijek diklofenak ubraja se u farmaceutska onečišćivala. Diklofenak iz ljudskog organizma izlazi dijelom nepromijenjem i dijelom u obliku raznih metabolita te dospijeva u otpadne vode. Konvencionalnim metodama obrade vode moguće je ukloniti samo dio prisutnog diklofenaka, stoga se okreće novim tehnologijama poput naprednih oksidacijskih procesa. U ovom radu ispitana je učinkovitost fotokataltičke razgradnje diklofenaka pod simuliranim Sunčevim zračenjem uz BiVO4 fotokatalizator. Ispitani su utjecaji metode sinteze fotokatalizatora, pH i dodatka modifikatora na fotokatalitičku razgradnju diklofenaka. Fotokatalizator sintetiziran metodom precipitacije pokazuje bolju fotokatalitičku aktivnost u odnosu na fotokatalizator sintetiziran hidrotermalnom metodom. Nadalje, dodatak modifikatora EDTA i povišenje pH pogoduju fotokatalitičkom uklanjanju diklofenaka. Najveća fotokatalitička aktivnost ostvarena je pri pH= 7,5 uz BiVO4 fotokatalizator sintetiziran precipitacijom s dodatkom EDTA. Ostvareno uklanjanje nakon 180 min provedbe procesa pod simuliranim Sunčevim zračenjem iznosi 34,5%, dok pod vidljivim zračenjem iznosi 56,1%.The population growth and global development are resulting in an increase in water consumption, leading to an increase in amount of waste water. Inadequately treated waste water enters water sources and contributes to pollution of the water environment. Pharmaceutical micropollutants which are detected in water around the world present a great jeopardy, due to the insufficient removal by conventional water treatment. Among them is diclofenac, non-steroidal anti-inflammatory drug. Diclofenac is being released into the environment partially unchanged and as its metabolites. Since diclofenac can only be partially removed by conventional water treatments it is necessary to develop new methods such as advanced oxidation processes. This study questions the efficiency of photocatalytical processes in diclofenac removal under simulated solar irradiation using BiVO4 photocatalyst. The study investigated influences of BiVO4 preparation method, pH and different additives on photocatalytic removal of diclofenac. Photocatalysts synthesized by precipitation method shows higher photocatalytic activity than photocatalysts synthesized by hidrothermal method. Furthermore, addition of EDTA and increase in pH result in higher photocatalytical activity. The highest photocatalytical activity has been achieved with pH= 7,5 and BiVO4 photocatalyst synthesized by precipitation method with addition of EDTA. Achieved diclofenac removal after 180 min is 34,5 % under simulated solar irradiation and 56,1 under visible light irradiation