Application of carbon-doped nano-magnesium oxide for catalytic ozonation of real textile wastewater: fractional factorial design and optimization

This study was aimed to prepare carbon-coated magnesium oxide (C-MgO) nanoparticles and investigate the catalytic activity of C-MgO in catalytic ozonation process (COP) for treating a real textile wastewater. A fractional factorial design was conducted to assess the interactions between operating parameters (pH, ozone flow rate, catalyst dose, reaction time) for the catalytic treatment of the textile wastewater via the C-MgO catalyst. The experiments of degradation and mineralization results matched well with those attained by the predicted models. Fractionate of the contribution reactive oxygen species (ROSs) and O-3 in COD removal indicated that ROSs had a dominant role in the mineralization of the recalcitrant compound in examining the textile wastewater sample. C-MgO showed better potential catalytic activities (synergetic effect = 57%) as compared with plain nano MgO and O-3 alone in COD elimination. The catalytic activity findings demonstrated that the mineralization rate of the COP with the C-MgO catalyst was 5.7 times that of the plain nano MgO/O-3 process. Based on the results, this report showed that the C-MgO catalyst could be applied in COP for treating real textile wastewaters.