Rapid loss of estrogenicity of steroid estrogens by UVA photolysis and photocatalysis over an immobilised titanium dioxide catalyst

Preliminary Study on the Removal of Steroidal Estrogens Using TiO2-Doped PVDF Ultrafiltration Membranes

“…The result implied that photolysis of E1 and E2 occurred in water, and E1 was easier to remove than E2. Estrogens have been reported to be amenable to transformation during UV treatment, with the light absorption attributed to the photoactive phenolic group [15,16], i.e., the photolysis producing compounds containing carbonyl groups [16]. Coleman et al used a recombinant estrogen assay based in yeast to follow the estrogenic activity of aqueous solutions (Cest.…”

“…Estrogens have been reported to be amenable to transformation during UV treatment, with the light absorption attributed to the photoactive phenolic group [15,16], i.e., the photolysis producing compounds containing carbonyl groups [16]. Coleman et al used a recombinant estrogen assay based in yeast to follow the estrogenic activity of aqueous solutions (C est of 10 µg¨L´1) of E1 and E2 after UVA photolysis, being most effective on E1, followed by E2 [15]. Ma et al studied the removal of three co-existing steroid estrogens, estrone (E1), 17β-estradiol (E2) and 17α-ethinyl estradiol (EE2), from aqueous solutions; when the ultraviolet irradiation intensity was 168 µW/cm 2 and the reaction time was 120 min, the E1 removal rate was 98.1%, and the removal rate of E2 was 37.0%.…”

“…The result showed that the nano-TiO2 addition can improve the estrogen removal rate under UV irradiation effectively. Coleman et al also showed that photocatalysis over TiO2 was more effective than direct photolysis at removing the estrogenic activity of E1 and E2 (initial concentrations of 10 μg L -1 ) from aqueous solutions [15]. At the same time, the content of titanium in water was tested by ICP-MS, and there was none detected at the experiment.…”

“…Water [15]. At the same time, the content of titanium in water was tested by ICP-MS, and there was none detected at the experiment.…”

Degradação de fármacos residuais por processos oxidativos avançados

“…54,64 Apesar da eficiência na mineralização de inúmeras espécies químicas de relevância ambiental, existem inconvenientes de ordem prática que dificultam o tratamento em larga escala, como dificuldade de penetração da irradiação no meio reacional e separação dos catalisadores que são utilizados na forma de finas suspensões. 47 Uma alternativa é o uso de sistemas que empregam o catalisador imobilizado, como reportado por Coleman et al 65 para a degradação do contraceptivo 17α-etinilestradiol. A fotocatálise heterogênea mostrou-se eficiente na degradação do mesmo, eliminando totalmente a atividade estrogênica em 50 min de tratamento.…”