Degradation kinetics of bisphenol A by catalytic wet oxidation with ruthenium-impregnated carbon nanosphere catalysts

Different countries in Europe has proposed different 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 has been still 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 synthetized with a mixture of resorcinol and formaldehyde and later a pyrolysis treatment it was impregnated by 1, 2, 5, 7 and 10% of ruthenium and activated with hydrogen at 350ºC. 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 (110-160ºC), 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 capacity two different potential models (r=k·(CBPA)^a and r=k·(C_BPA)^a·P^b·CRu^c) were used for simulating the kinetic behavior of BPA from the adjustment of the experimental data obtained for CWAO reactions. It was also tested different loads of ruthenium (1-10%) in the degradation of BPA. The both adjustments had a correlation factor of 0.98 and reproduced well all the experiments, being better those ones with 20 mg·L^-1 of initial concentration of BPA. The degradation of BPA was above 97% at 90 minutes of reaction time from 2% of Ru in the catalyst.