Performance comparison of torus and magnetically-stirred reactor for the enzymatic elimination of phenol

Abstract

The goal of this work is the comparison of the performances of a torus and a stirred reactor for the enzymatic elimination of phenol. High degrees of conversion were obtained in both reactors for the three initial concentrations of phenol tested. In the case of the torus reactor, around 97%, 85% and 56% of phenol conversion were obtained for initial phenol concentrations of 0.5, 1.1 mM and 1.6 mM respectively, with the optimal concentrations of hydrogen peroxide. In the case of using the magnetically-stirred vessel, the extension of the phenol elimination was around 89%, 67% and 58% for an initial phenol concentration of 0.5 mM, 1.1 mM and 1.6 mM respectively. No significative differences were observed for both reactors, nevertheless the phenol conversion that was always higher for the torus reactor. Also, the values of the initial reaction rates were always lower in the stirred reactor, suggesting that the mixing in the torus reactor is more effective. The optimal H2O2 initial concentration to achieve the highest conversion of phenol has to be a ratio equal to 1 between the phenol and the H2O2 initial molar concentration. The excess of hydrogen peroxide in the mixture inhibited the activity of the enzyme, by the conversion of the peroxidase to inactive forms, provoking a reduction of the phenol conversion.