The authors are thankful to the Brazilian agencies
CNPq, CAPES and Fundação Araucária for financial support of
this work, C2MMa
and Brazilian Mining and Metallurgy Company
– CBMM and are grateful to the Foundation for Science and Technology
(FCT, Portugal) and FEDER (Fundo Eropeu de Desenvolvimento
Regional) under Programme PT2020 for financial support to CIMO
(UIDB/00690/2020).
This study describes the application of Ag/Nb2O5 catalysts, suspension and spheres alginate immobilized for the degradation
of 17α-Ethinylestradiol (EE2). The techniques used to characterize the photocatalysts were as follows: X-ray diffraction
(XRD), N2
adsorption–desorption analysis (BET), point charge zero charge (PZC), scanning electron microscopy (SEM)
and energy dispersive X-ray spectroscopy (EDS). Different catalyst calcination temperatures were studied by keeping the
silver metal loading at 5%. Among the operational conditions analyzed were pH, catalyst concentration, the emitting source
of radiation and the inlet flow rate (in continuous operation). The results of the experiments performed initially with the
catalyst in suspension revealed that the highest catalytic activity in the degradation of EE2 was the 5%Ag/Nb2O5 catalyst
calcined at 973 K, which removed 77.7% of the initial pollutant concentration in 120 min of reaction. The immobilization
of the catalyst in alginate spheres resulted in a degradation reduction, being able to degrade 69.2% of the initial EE2 in a
batch system. In the continuous system, the immobilized catalyst obtained a total degraded of 37.3%, with a flow rate of 10
L·h−1. Catalyst reuse was promising, even dropping the removal, degrading around 27% of the initial EE2 concentration in
the third cycle of use.
