engleski

Degradation of 17b-estradiol in water by a novel nanocomposite photocatalyst

The negative environmental impact of pharmaceuticals has caused a great concern. In recent years the drawbacks of conventional wastewater treatment technologies for their removal have been identified. 17β-estradiol (E2) has recently been included in the watch-list of the EU Water Framework directive (2013/39/EU). The applications of E2 include contraception, hormone therapy and treatment of prostate cancer. However, E2 in the environment acts as a carcinogenic substance and as an endocrine disruptor. Advanced oxidation processes have shown promise for successful removal of persistent organic micropollutants. In this study solar driven photocatalytic decomposition of E2 in water was studied. In that purpose, different photocatalytic materials were investigated: commercial TiO2 (AEROXIDE P25), and two TiO2- based composites TiO2-FeZ and TiO2-SnS2. The first composite material was prepared by combining TiO2 and iron-exchanged zeolite of ZSM5 type, while later composite material was obtained by combining TiO2 and another semiconducting material SnS2 (MKN-900). The photocatalytic processes were conducted using immobilized photocatalysts in a form of thin film on glass supports, which were prepared by spin coating technique. In order to study the influence of parameters of applied photocatalytic treatment, pH, oxidant (H2O2) concentration and catalyst composition, on the effectiveness of E2 degradation the design of experiments combined with response surface modeling were employed. It was established that the most effective catalyst under induced solar irradiation was TiO2-FeZ, yielding 78.01 % of E2 degradation after 90 min treatment that was significantly higher than those obtained by processes using TiO2 and TiO2- SnS2 (41.58 and 34.44%, respectively). The influence of water matrix composition, i.e. presence of nitrates, carbonates and natural organic matter, on the effectiveness of E2 degradation by solar/TiO2-FeZ/H2O2 process was studied as well.

nanocomposite photocatalyst ; estradiol ; AOP

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