Electro‐Oxidation of the Pharmaceutical Furosemide: Kinetics, Mechanism, and By‐Products

Abstract

Furosemide is a widely prescribed diuretic whose unambiguous presence in water appointed it as an emerging pollutant. This work focuses on the electrochemical degradation of this drug in aqueous solutions by electrochemical advanced oxidation processes, electro‐Fenton and anodic oxidation, using Pt/carbon‐felt and boron doped diamond (BDD)/carbon‐felt cells with H2O2 electrogeneration. The higher oxidation power of the electro‐Fenton process using a BDD anode was demonstrated. The oxidative degradation of furosemide by electrochemically generated •OH radicals follows a pseudo‐first order kinetics. The absolute rate constant of the oxidation reaction of furosemide by •OH was determined using a competition kinetics method and found to be 3.4 × 109 M−1 s−1. The evolution of the total organic carbon removal during the treatment as a mineralization efficiency parameter was investigated. It was found that the electrochemical degradation of furosemide yields formation of aromatic by‐products which are oxidized afterwards to aliphatic carboxylic acids before their conversion to CO2 and inorganic ions (NH4+, NO3–, Cl–, and SO42–). The toxicity assessment by the Microtox® method revealed formation of oxidation reaction intermediates more toxic than the parent molecule. Nevertheless, the overall results confirm the high effectiveness of anodic oxidation and electro‐Fenton processes for the removal of furosemide and its by‐products from aqueous media.

Intensification of UV-C treatment to remove emerging contaminants by UV-C/H2O2 and UV-C/S2O82−: Susceptibility to photolysis and investigation of acute toxicity

“…This result indicates that it is not adequate to consider the EE/O values alone for identifying the optimal treatment method. FRSM was reported to be non-toxic to Allivibrio fischeri [54], yet its products of photolysis and electro-Fenton degradation are considered toxic [74,75]. In the present study, before treatment, the FRSM solution exhibited a beneficial stimulatory effect, known as hormesis, upon the photobacteria (Figure 3).…”

Effect of electrogenerated hydroxyl radicals, active chlorine and organic matter on the electrochemical inactivation of Pseudomonas aeruginosa using BDD and dimensionally stable anodes

“…This transformation is minimized in the so-called non-active anodes like PbO 2 , SnO 2 and borondoped diamond (BDD), which present a large ability to degrade the organic load [1,5,6]. It has been found that BDD thin-film electrodes are the most powerful anodes in EO because they exhibit the highest O 2 -overvoltage and a very weak interaction with  OH and organics, thus favoring the complete mineralization of aromatics and linear aliphatic compounds [10][11][12][13][14][15][16][17][18]. Nevertheless, the main drawbacks of the BDD anode are its high cost and the simultaneous production of other weaker oxidants like ozone and peroxodifulfate (S 2 O 8…”

Optimization of process parameters for the electrochemical oxidation treatment of petroleum refinery wastewater using porous graphite anode

“…Electrochemical Oxidation (EO) treatment as a competitive technology has been used for treating different kinds of industrial wastewaters like pulp and paper plants, distillery, tannery, and textile industry. EO destruction of wastewaters containing phenolic compounds, such as dyes, poly-aromatic organic compounds, arsenic, and sulfidic spent caustic is also reported in the literature [15][16][17][18][19]. The electrochemical oxidation method offers a clean and powerful method for the mineralization of organic contaminants in water.…”