[en] Full text: Nowadays, the water reserves contamination by pesticides and there are not efficient methods to remove them are major unresolved issues. [1]. Using the advanced oxidation process (AOP) for degradation of atrazine, with Nb₂ O₅ nanoparticles as a photocatalyst, was more efficient than traditional methods. [2]. In this work, it was used the same semiconductor, obtained by different methods (Hydrothermal and polymeric precursor), using different sources of Nb (NH₄ [NbO(C₂O₄ )₂H₂O]H₂O and NbCl₅ ), to study the degradation of the Imazaquin pesticide. The samples were characterized by SEM, XRD, Raman and IR spectroscopies. The response of the degradation of imazaquin was analyzed by UV-vis spectroscopy. Degradation kinetic studies were performed. It was observed that in all cases, the photocatalysts were effective, degrading Imazaquin molecules. The sample with the best result was synthesized by the polymeric precursor method using, 3:1 citric acid to ammonium niobium oxalate and crystallized at 600°C in a Nb₂O₅ orthorhombic structure. (k-value = 0.0169 / k-value imazaquin = 0.0081). References: [1] D. M. Hamby Sci. Total Environ 1996, 191(3), 203 [2] Dos Reis, E. D. W.; Neves Jr., L. F.; Paris, E. C.; Analysis of the photocatalytic effect of Nb2O5 on pesticides in water. In: ENCONTRO DA SOCIEDADE BRASILEIRA DE PESQUISA EM MATERIAIS, 12, 2013, Campos do Jordão. Resumos. (author)