Preparation and Application of Sodium–Lanthanum Molybdate for the Photocatalytic Degradation of Coomassie Brilliant Blue G-250 Dye

This study reports on the synthesis, characterization, and application of sodium-lanthanum molybdate [NaLa(MoO₄)₂] as a photocatalyst in the degradation process of Coomassie Brilliant Blue G-250 (CBB-250), an environmentally toxic and recalcitrant dye derived from triphenylmethane. The highlighted ceramic material was produced by coprecipitation, and its properties were studied using a range of physicochemical techniques including compositional, crystallographic, and morphological analyses. Among the most relevant information, X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy confirmed the formation of NaLa (MoO₄)₂ crystals with a tetragonal arrangement. Additionally, the scanning electron microscope (SEM) images provide evidence of the production of overlapping plate-like microstructures. The nitrogen adsorption isotherms demonstrated that the molybdate obtained exhibits mesoporous organization, with a surface area and pore diameter equivalent to 45.7 m² g^-1 and 6.54 nm, respectively. Photocatalytic tests, performed under ultraviolet light irradiation for 120 min, indicated that NaLa(MoO₄)₂ has high oxidative reactivity, achieving a degradation of >95% of the CBB-250 dye present in the system. The reaction velocity constants, estimated in accordance with the Langmuir-Hinshelwood equation, substantiate that NaLa(MoO₄)₂ enhances the reaction kinetics (13.7 × 10^-3 min^-1) throughout the photochemical treatment. In light of the growing scientific interest in effective strategies for the removal of emerging pollutants from contamination matrices, NaLa(MoO₄)₂ represents a promising avenue for the development of innovative technologies in this field.