Pharmaceutical products (PPs) are considered as emerging micropollutans in wastewaters, river and seawaters, and sediments. The biodegradation of PPs, such as ciprofloxacin, amoxicillin, sulfamethoxazole, and tetracycline by enzymes in aqueous solution was investigated. Laccase from Trametes versicolor was immobilized on silica monoliths with hierarchical meso-/macropores. Different methods of enzyme immobilization were experienced. The most efficient process was the enzyme covalent bonding through glutaraldehyde coupling on amino-grafted silica monoliths. Silica monoliths with different macropore and mesopore diameters were studied. The best support was the monolith featuring the largest macropore diameter (20 µm) leading to the highest permeability and the lowest pressure drop and the largest mesopore diameter (20 nm) ensuring high enzyme accessibility. The optimized enzymatic reactor (150 mg) was used for the degradation of a PP mixture (20 ppm each in 30 ml) in a continuous recycling configuration at a flow rate of 1 ml/min. The PP elimination efficiency after 24 h was as high as 100% for amoxicillin, 60% for sulfamethoxazole, 55% for tetracycline, and 30% for ciprofloxacin.

Silica monoliths with uniform macro-/mesoporous structures (20 µm 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 NH 2 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 hours 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.

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