Tetracycline (TC) degradation via hydrodynamic cavitation (HC) combined Fenton's reagent: Optimizing geometric and operation parameters

Abstract

In this study, the tetracycline degradation was conducted by using hydrodynamic cavitation (HC) device. The influences of Venturi tube parameters (divergence angle, throat length and convergent angle) and the operation conditions (inlet pressure (1.0-5.0 bar), initial tetracycline concentration (5.0-20 mg/L) and addition of some common inorganic anions) on tetracycline degradation were investigated. The results showed that a strong HC effect can be obtained when the Venturi tube with 22° half convergent angle, 2.0 mm throat length and 6.0° half divergence angle is used. The tetracycline degradation ratio can reach 83.17% when inlet pressure and initial concentration were 3.0 bar and 5.0 mg/L, respectively. The tetracycline HC degradation can be intensified by CO32− but inhibited by NO3− and SO42−. Liquid Chromatography-Mass Spectrometry result shows that tetracycline can be decomposed into small molecules in HC process. Total organic carbon reduction testifies that tetracycline can be effectively mineralized into H2O, CO2 and inorganic ions. The addition of Fenton's reagent can further enhance the tetracycline HC degradation efficiency. It is speculated that HC technology assisted by Fenton's reagent can be used for large-scale treatment of antibiotic wastewater.