Aggrandized catalytic performance of transition metal doped strontium hexagonal ferrites for the treatment of malevolent organic pollutants

The present study accentuates at the employment of transition metal doped strontium hexagonal ferrites (SrMFe11O19, M = Cr, Mn, Fe, Co, Cu and Zn) as catalyst for the instigation of potassium peroxymonosulphate towards contaminant degradation for the first time. The successful synthesis of the catalyst was established via numerous techniques such as XRD, FE-SEM, HR-TEM and VSM. The powder X-ray diffraction patterns confirmed the successful formation of hexagonal phase with P63/mmc space group. The detailed surface structure of the synthesized materials was scrutinized through FE-SEM and HR-TEM techniques showcasing hexagonal morphology as predicted by powder XRD technique. The comparative evaluation of catalytic performance of synthesized materials towards the activation of two inorganic oxidants (Hydrogen Peroxide and Potassium Peroxymonosulphate) was carried out for the oxidative degradation of methylene blue, methyl orange, p-nitro phenol and tetracycline. All the synthesized materials were perceived to be highly competent towards the degradation of model pollutants. SrMnFe11O19 portrayed best performance for the oxidative-degradation of model pollutants with rate constant values 1.74 × 10−1 min−1 for MB, 3.04 × 10−1 min−1 for MO, 1.27 × 10−1 min−1 for PNP and 0.73 × 10−1 min−1 for TC using HP as oxidant and 0.39 × 10−1 min−1 for MB, 2.90 × 10−1 min−1 for MO, 0.69 × 10−1 min−1 for PNP and 1.69 × 10−1 min−1 for TC using PMS as oxidant. PMS was witnessed to be a better oxidant in contrast with HP owing to its applicability at wider pH range and higher selectivity; moreover it does not entail any external light source for stimulation.