Catalyst synthesis and application in oxidation assays

Hydrocarbons contaminated soil remediation is a critical issue since soil is a complex media, mainly because of its heterogeneity. Thereby literature lacks studies involving in situ chemical oxidation focusing on soil remediation. Clays can be an important proposal as support to heterogeneous catalyst for oxidation process, due to their natural abundance and eco-friendly characteristic. Different clay-based catalysts were synthesized through 23 experimental design varying sodium hydroxide (NaOH), ferrous sulfate (FeSO4) and ferric sulfate (Fe3(SO4)2) concentrations. A set of different synthesized catalysts were applied in phenanthrene (PHE) contaminated soil oxidation to evaluate the activation of the sodium persulfate (SP) and hydrogen peroxide (HP) oxidants. Values of PHE removal from contaminated soil were used as response. At the experimental conditions studied, most of the produced catalysts proved to be efficient in activating both oxidants, achieving around 80% of PHE removal from soil. Control assays presented that around 20% of PHE can be naturally transferred to liquid phase and PHE removals from soil did not occur during oxidation without clay modification, i.e., using raw clay. The selected catalyst obtained the best oxidant activation with NaOH concentration of 0.625 M, ferrous sulfate concentration of 137.25 gL-1 and ferric sulfate concentration of 274.50 gL-1