Augmented 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 (PMS) towards contaminant degradation for the first time. The successful synthesis of the catalyst was established via various techniques such as XRD, FE-SEM, HR-TEM and VSM. The comparative evaluation of catalytic performance of synthesized materials towards the activation of two inorganic oxidants (Hydrogen Peroxide (HP) and Potassium Peroxymonosulphate (PMS)) was carried out for the oxidative degradation of methylene blue (MB), methyl orange (MO), p-nitro phenol (PNP) and tetracycline (TC). All the synthesized materials were perceived to be highly competent for 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. (author)