Degradation Kinetics of Bisphenol A by Catalytic Wet Oxidation with Ruthenium-Impregnated Carbon Nanosphere Catalysts

Abstract

Different countries in Europe have proposed some restrictions about bisphenol A (BPA), considered an endocrine disruptor, for the production of food packing and toys for children, for example, Denmark, France, Sweden, Belgium, Austria and Norway. However, it is still being found in wastewater effluents. In this study, BPA was degraded by catalytic wet air oxidation employing ruthenium-impregnated carbon nanosphere catalysts (CNS). The catalyst was synthesized with a mixture of resorcinol and formaldehyde and later, a pyrolysis treatment was impregnated by 1, 2, 5, 7 and 10% of ruthenium and activated with hydrogen at 350 °C. The experimental installation was a batch Hastelloy high-pressure reactor of 100 mL of volume with an electrical jacket and a variable-speed magnetic drive. The concentration of BPA was followed by high-performance liquid chromatography. After the study of different experiment variables (temperature (110–150 °C), pressure (20–50 bar), initial concentration of BPA (5–30 mg L−1) and catalyst mass (50–300 mg)) in a batch reactor of 100 mL of volume, two different potential models (r = k CaBPA and r = k CaBPA Pb Cc Ru) were used for simulating the kinetic behavior of BPA from the adjustment of the experimental data obtained for CWAO reactions. It also tested different loads of ruthenium (1–10%) in BPA degradation. Both adjustments had a correlation factor of 0.98 and reproduced all the experiments well, being better than those ones with 20 mg L−1 of initial concentration of BPA. BPA degradation was above 97% at 90 min of reaction time from 2% of Ru in the catalyst.