Abstract (EN):
In this work, an advanced oxidation process using ozonation combined with hydrogen peroxide (H2O2) and catalyzed by manganese (Mn2+) in alkaline conditions was investigated to degrade the organic matter present in a synthetic dairy wastewater (SDW) with a chemical oxygen demand (COD) of 2.3 g L-1. The effect of independent factors such as pH (7-13), H2O2/O-3 ratio (0-1), and Mn2+ concentration (0-1.71 g L-1) has been evaluated and the process optimized using a factorial design and a central composite design (CCD) in sequence. The experiment has been made in batch trials using 2 L of SDW in which ozone was bubbled during 2 h and samples collected for COD analyses, used as response variable. In the factorial experiment, the effect of H2O2 was not significant for all the ratios tested (p value > 0.10), and the effects of the pH and Mn2+ were positive and significant (p value = 0.05). In the CCD, the linear (positive) and quadratic (negative) effects of pH and Mn2+ were significant (p values = 0.05 and = 0.10, respectively). According to the response optimizer, the optimal condition for the ozonation catalyzed by manganese at alkaline medium (COD removal of 69.4%) can be obtained in pH 10.2 and Mn2+ concentration of 1.71 g L-1. Moreover, COD removals above 60% can be obtained for pH values of 9.5 to 11 and Mn2+ concentrations of 0.6 g L-1.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
11