engleski

Solar Driven Degradation of Pharmaceuticals Using Immobilized Composite Photocatalyst

In spite of their ubiquity in water environment and documented harmful behavior, most of pharmaceuticals are not being regulated by drinking water standards. However, during the recent prioritization in the field of water legislation the three pharmaceutical compounds ; 17b-estradiol, 17a-ethinylestradiol and diclofenac (DCF), are added to the "watch list" in order to gather monitoring data for the purpose of supporting future prioritization. DCF, widely used as analgesic, antiarthritic and anti- rheumatic non-steroidal anti-inflammatory drug, is frequently detected in drinking water sources and wastewater effluents due to limited removal by common municipal wastewater treatment plants. Such findings impose a need for changing the current practice in wastewater treatment, by the integration of advanced technologies to achieve satisfactory treated effluents. Accordingly, the study explores the potential of immobilized TiO2 ; -based composite photocatalyst for solar driven treatment of diclofenac (DCF). The hypothesis is that the solar photocatalytic treatment of water containing recalcitrant organic pollutants would be more efficient when composite materials arc applied instead of pure AEROXIDE TiO2 P25. In that purpose, we applied two composite type photocatalysts made of two semiconducting materials: TiO2 ; and tin sulfide (SnS2). The first composite material is made during immobilization by combining two commercial (nano) materials: AEROXIDE TiO2 P25 and SnS2 MKN- 900, while second composite is prepared using one-step synthesis by sol-gel method. Their effectiveness in DCF removal and degradation were compared with AEROXIDE TiO2 P25 as reference photocatalytic material. The set hypothesis was confirmed ; TiO2-SnS2 photocatalyst showed higher activity under solar irradiation than reference TiO2. The influence of process parameters on the effectiveness of applied solar driven photocatalytic process (solar/TiO2-SnS2/H2O2) was studied using response surface modeling. The dominant influence of pH on process effectiveness can be attributed to the role of DCF adsorption within degradation mechanism by solar/TiO2- SnS2/H2O2. The photocatalyst composition was found to be rather important for DCF degradation yield, as well as oxidant concentration.

pharmaceuticals ; solar driven degradation ; photocatalyst ; diclofenac

nije evidentirano