Magnetically separable, barium hexaferrite (BaFe12O19) nanoplatelets were synthesized at various temperatures by cost-effective, molten salt technique and its photocatalytic activity was compared with commercially available TiO2. BaFe12O19 nanostructures were characterized by using UV-vis-DRS, FE-SEM, XRD, BET, and Raman and further, subjected to photo-catalytic degradation of an organic pollutant, hexahydro-1,3,5-trinitro-1,3,5 triazine (RDX) under UV and visible light. The reaction parameters, degradation kinetics, and mechanism were thoroughly studied, and optimum reaction conditions were evaluated. The degradation products were analyzed by HPLC, LCMS, and TOC. The BaFe12O19-800 degrees C nanoplatelets (0.6 g.L-1) with UV-vis lamp irradiation were efficient and economical to degrade 40 mg.L-1 of RDX below the discharge limits (<0.035 mg.L--(1)) in 300 min whereas TiO2 showed 4 mg.L-1 of unreacted RDX at similar conditions. Kinetic rate of BaFe12O19 and TiO2 were observed to be 0.017 and 0.003 min(-1), respectively. Magnetic separation of BaFe12O19 for recovery and recycling is also reported.