One of the most important problems that the world is currently facing in terms of its impact on the environment is figuring out how to properly manage textile effluents. Photocatalysis has been shown to be successful in the removal of intractable chemicals and is regarded as a viable wastewater treatment technology. This work focused on the photocatalytic degradation of rhodamine-B (RB) in an aqueous solution, as well as the photocatalytic behavior of niobium pentaoxide (Nb2O5) as a photocatalyst was tested. It is important to note that good photocatalytic efficiency is highly dependent on the operating conditions. There are several process parameters that influence RB photocatalytic degradation, including the amount of photocatalyst (Nb2O5) used, the concentration of RB at the start of the reaction, and the pH of the solution optimized under visible-light irradiation. According to the findings, the conditions in which the greatest amount of RB was degraded were those in which the concentration of the catalyst was 10 mg/l, the dosage of the catalyst was 1 mg/l, and the pH was 11. The results also revealed that after utilizing the catalyst three times in a row, catalyst efficiency was maintained, and the degradation rate was maintained at a greater level. © 2022 The Authors.