Conventional treatments are often ineffective for removing the persistent pharmaceutical diclofenac (DCF), reinforcing the need for advanced oxidation strategies. Electrochemical oxidation (EO) is a promising alternative, yet studies employing continuous-flow reactors remain limited, particularly regarding by-product modelling and the reconstruction of complete degradation pathways. This work presents a continuous electrochemical reactor equipped with a Magnéli-phase TiₙO₂ₙ₋₁ mesh anode and a Ti/IrO₂–Ta₂O₅ mesh cathode for the EO of DCF in water. The effect of the flow rate was investigated and a degradation pathway was proposed, which involves parallel hydroxylation of DCF to 5-hydroxy-DCF and C–N bond cleavage to form 2,6-dichloroaniline, followed by successive oxidation to downstream intermediates. Kinetic modelling under steady-state and unsteady-state conditions was performed, comparing ideal plug-flow (PFR) and continuous stirred-tank (CSTR) reactor behaviour. Results show that the CSTR model provides the closest agreement with experimental data at all investigated flow rates, with the best fit obtained at 50 rpm (flow rate = 2.96 mL min⁻¹, residence time = 167.0 min).
Diclofenac degradation through electro-oxidation using a continuous reactor equipped with meshed electrodes: removal efficiency, degradation pathways and reactor modelling
Fenti A.;Falco G.;Iovino P.;Chianese S.;Musmarra D.
2026
Abstract
Conventional treatments are often ineffective for removing the persistent pharmaceutical diclofenac (DCF), reinforcing the need for advanced oxidation strategies. Electrochemical oxidation (EO) is a promising alternative, yet studies employing continuous-flow reactors remain limited, particularly regarding by-product modelling and the reconstruction of complete degradation pathways. This work presents a continuous electrochemical reactor equipped with a Magnéli-phase TiₙO₂ₙ₋₁ mesh anode and a Ti/IrO₂–Ta₂O₅ mesh cathode for the EO of DCF in water. The effect of the flow rate was investigated and a degradation pathway was proposed, which involves parallel hydroxylation of DCF to 5-hydroxy-DCF and C–N bond cleavage to form 2,6-dichloroaniline, followed by successive oxidation to downstream intermediates. Kinetic modelling under steady-state and unsteady-state conditions was performed, comparing ideal plug-flow (PFR) and continuous stirred-tank (CSTR) reactor behaviour. Results show that the CSTR model provides the closest agreement with experimental data at all investigated flow rates, with the best fit obtained at 50 rpm (flow rate = 2.96 mL min⁻¹, residence time = 167.0 min).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
