Photo-assisted Electro-Fenton process for degradation of ampicillin from pharmaceutical wastewater: Optimization and determining mechanism

Antibiotics are designed specifically as a drug to treat or prevent infective diseases in human or animal body. The use of antibiotics has become an indispensable in human life and the global market consumption of these drugs increase steadily every year [1]. For preventing or treating infections in humans or animals, only some parts of the antibiotics given dose are metabolized and the rest are excreted still as active compound [2]. Therefore, treatment of antibiotic and its degradation products is crucial. The current work aimed to evaluate the efficiency of Photo Electro-Fenton (PEF) process for removal of ampicillin from pharmaceutical wastewater. Optimization of process parameters: initial ampicillin concentration, pH, current density, irradiance of UV, reaction time and H2O2 dosage, was achieved using Central Composite Design (CCD) approach in combination with Response surface methodology (RSM). The results showed that optimum conditions for removal of ampicillin was found to be 95.3% Provided that initial pH of 3, reaction time of 22 min, concentration of 16.4 mg.L-1, H2O2 dosage of 110 µL, 90 mW.cm-2 irradiance of UV, and current density of 2.9 mA.cm-2. H2O2 dosage had the greatest influence on ampicillin removal among other variables. The hydroxyl free radicals produced by the hydrogen peroxide combined with in situ electro generated Fe2+ and irradiance of UV (PEF process) was the main mechanism to removal the ampicillin in the reactor. The obtained results revealed that the experimental kinetic data was represented well by using pseudo-first-order model. The PEF process is environmentally friendly since it does not involve the use of harmful chemical reagents, besides it is easy to handle and the reactor used is Simple.