Photocatalytic degradation of rhodamine B using Nb2O5 synthesized with different niobium precursors: Factorial design of experiments

Abstract Niobium pentoxide (Nb2O5) was synthesized by the microwave-assisted hydrothermal method using two different niobium precursors: niobium ammoniacal oxalate (P1) and niobium chloride (P2). The XRD result confirms the presence of Nb2O5 with low crystallinity for both precursor samples. The SEM images show differences between the material morphologies but with the same aggregation particle characteristics. Photocatalytic degradation of the rhodamine B (RhB) dye was performed using both samples of Nb2O5 as a photocatalyst under UVC illumination using a 24 factorial design experimental method. The studied variables were the type of precursor (P1 and P2), the RhB concentration (1 × 10−5 and 3 × 10−5 M), the Nb2O5 photocatalyst dosage (25 and 50 mg), and the time of the photocatalysis analysis (30 and 60 min), verifying the influence on the RhB dye removal efficiency. The factorial design showed that all variables had a significant effect on the process, but the variables with the most influence were RhB concentration and photocatalysis time. For both precursors, the samples that showed greater removal efficiency were those under conditions 1 × 10−5 M, 50 mg, and 60 min, obtaining 92.87% and 98.99%, respectively. The high rate of RhB removal suggests that the Nb2O5 obtained by microwave-assisted hydrothermal synthesis has the potential to be used in photocatalytic processes to remove organic pollutants from effluents.