Catalysis Today, Vol.362, 62-71, 2021
Enzymatic monolithic reactors for micropollutants degradation
Silica monoliths with uniform macro-/mesoporous structures (20 mu m and 20 nm macro- and mesopores diameters, respectively), high porosity (83 %) and high surface area (370 m(2) g(-1)) were prepared. The monoliths were grafted with amino groups (0.9 mmol NH2 g(-1)) and used to immobilize laccase from Trametes versicolor by covalent grafting with glutaraldehyde (GLU) (1.0 mmol GLU g(-1)) leading to an ABTS activity of 20 U g(-1). Immobilization yield was 80 %, based on the difference of initial and final activity of enzymatic solution used for immobilization. Enzymatic monoliths were used for the degradation of tetracycline (TC) in aqueous solution (20 mg L-1) in continuous flow with recycling configuration. TC degradation efficiency was found to be 40-50 % after 5 h of reaction at pH 7. Enzymatic monoliths were used during 75 h of sequential operation without losing activity. A Steady-state computational fluid dynamics (CFD) model based on Michaelis Menten reaction kinetics, allowed computing TC degradation efficiency.