Experimental and modeling of tetracycline degradation in water in a flow-through enzymatic monolithic reactor

• Published in: Environmental science and pollution research international 2022-10, Vol.29 (50), p.75896-75906
• Main Authors: Ahmad, Sher, Sebai, Wassim, Belleville, Marie-Pierre, Brun, Nicolas, Galarneau, Anne, Sanchez-Marcano, José
• Format: Article
• Language: English
• Subjects: Antibiotics; Aquatic Pollution; Aqueous solutions; Atmospheric Protection/Air Quality Control/Air Pollution; Chemical and Process Engineering; Chemical Sciences; Configurations; Degradation; Degradation products; Depletion; Earth and Environmental Science; Ecotoxicology; Engineering Sciences; Environment; Environmental Chemistry; Environmental Health; Environmental science; Environmental Sciences; Enzymes; Flow rates; Flow velocity; Fluidized bed reactors; Laccase; Membranes; Oxygen; Oxygen content; Oxygen saturation; Reactors; Research Article; Silica; Simulation; Substrates; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-022-21204-y

In this work, the laccase from Trametes versicolor was immobilized in highly porous silica monoliths (0.6-cm diameter, 0.5-cm length). These monoliths feature a unique homogeneous network of interconnected macropores (20 μm) with mesopores (20 nm) in the skeleton and a high specific surface area (330 m 2 /g). The enzymatic monoliths were applied to degrade tetracycline (TC) in model aqueous solutions (20 ppm). For this purpose, a tubular flow-through reactor (FTR) configuration with recycling was built. The TC degradation was improved with oxygen saturation, presence of degradation products, and recirculation rate. The TC depletion reaches 50% in the FTR and 90% in a stirred tank reactor (CSTR) using crushed monoliths. These results indicate the importance of maintaining a high co-substrate concentration near active sites. A model coupling mass transfers with a Michaelis-Menten kinetics was applied to simulate the TC degradation in real wastewaters at actual TC concentration (2.8 10 −4 ppm). Simulation results show that industrial scale FTR reactor should be suitable to degrade 90% of TC in 5 h at a flow rate of 1 mL/min in a single passage flow configuration. Nevertheless, the process could certainly be further optimized in terms of laccase activity, oxygen supply near active sites, and contact time.