Investigating photocatalytic degradation of o-nitrophenol and p-nitrophenol over efficient CoO-Fe2O3@SiO2@TiO2 nanocomposite: rank annihilation factor analysis approach

In the present work, photocatalytic degradations of o-nitrophenol (ONP) and p-nitrophenol (PNP) were carried out using CoO-Fe2O3@SiO2@TiO2 nanocomposite as an efficient and cost-effective photocatalyst under simulated solar irradiation. Due to the acid-base property of nitrophenols, the kinetic degradations of the analytes were investigated thoroughly at two acidic and basic media where the neutral and anionic forms of the analytes were present in the aqueous media. For each experiment, time-spectral data were collected and analyzed by rank annihilation factor analysis approach to discover the underlying photoreactivity of the components. In this study, 3 mg of nanophotocatalyst led to rapid degradation of 100 mL of nitrophenols solutions, 40 mu g L-1 of ONP and 20 mu g L-1 of PNP, without the need for post-treatment removal of the photocatalyst from aqueous solutions owing to the magnetic feature of the nanocomposite. The results revealed that the kinetic rate constants are highly dependent on the pH of solution because pH makes the analytes be in neutral or anionic forms, a fact which helps the researchers improve the efficiency of the photocatalytic reactions of nitrophenols by taking into account the factors leading to simple changes of analyte structures.