ABSTRACT
Undoped and copper doped goethite catalysts were synthesized and applied in Fenton depuration of Kaduna refinery wastewater. The percentage of copper in the doped catalysts are 0.2 wt% copper in Cu-doped (A), 1.6 wt% copper in Cu-doped (B) and 3.3 wt% copper in Cu-doped (C), respectively. Characterization of the catalysts were done using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Absorption Spectrophotometer (AAS) and Surface Area Analysis. An experimental design matrix was used to evaluate the individual and combined effects of the process variables. Response surface methodology (RSM) was applied with a central composite design (CCD), and models were developed. The optimal conditions are pH of 3, 360 minutes reaction time, catalyst loading of 55mg/L and hydrogen peroxide dosage of 1.1g/L. Astonishingly, appreciable depuration percentage was achieved at near neutral pH, 67.44% was achieved by the undoped goethite catalyst, 79%, 82.56% and 83.72% were achieved by the Cu-doped A, B and C goethite catalysts, respectively. The obtained models for the undoped and doped catalysts gave R-square (R2) values of 0.9471, 0.9794, 0.9371 and 0.9407, respectively which showed that the experimental data fitted the model fairly well, depicting the viability and reliability of the model. It was observed that the Cu-dopedgoethite catalysts yielded improved depuration, confirming that the doped catalysts have great potential as an efficient tool for Fenton depuration of petroleum refinery wastewater.