Photocatalytic treatment of wastewater containing Rhodamine B dye via Nb2O5 nanoparticles: effect of operational key parameters

Heterogeneous photocatalysis has proved to be a useful tool for the degradation of water pollutants over the past 30years. In this work, the photocatalytic decolorization of Rhodamine B (RhB) dye as a model compound has been studied by using nano-sized Nb2O5 semiconductor as a photocatalyst. Structural and textural features of the Nb2O5 sample were characterized by X-ray diffraction, scanning electron microscope, UV-vis DRS, and Brunauer-Emmett-Teller techniques. As a result, the orthorhombic Nb2O5 particles displayed nearly spherical shape with the average crystalline size and the band gap energy of 43.7nm and 2.9eV, respectively. Different parameters of decolorization reaction like dye concentration, catalyst amount, pH, and H2O2 concentration have been studied. The optimum conditions for the photo treatment of the dye were initial concentration 10mgL(-1) of dye, catalyst concentration 0.5gL(-1), and pH 4. The optimum value of H2O2 concentration for the conditions used in this study was 700mgL(-1). Moreover, the efficiency of photo-Fenton process either alone or in conjunction with Nb2O5 and a dark-Fenton process as a control experiment were evaluated. The combination of photo-Fenton and Nb2O5 catalysts was found to be most effective for the treatment of such type of wastewaters.