Unravelling the efficacy of pencil graphite anode decorated with PdCu@γ-Fe2O3 nanoparticles in the electro-oxidation of amoxicillin: Insights into kinetics, oxidative pathways and toxicity evaluation

Abstract

Indiscriminate use of antibiotics has resulted in the occurrence of antibiotic residues in sediments, water bodies and industrial sewage, causing ill effects on aquatic organisms and humans. Electrochemical oxidation process via in-situ generation of strong oxidant •OH is the promising method for the removal of pollutants. In this work, PdCu/γ-Fe2O3 NPs electrodeposited pencil graphite electrode (PdCu/γ-Fe2O3@PGE) has been projected as a cost-effective anode for electro-oxidation of amoxicillin (AMX), while bare PGE was used as a cathode to generate H2O2. The electrochemical measurements showed that PdCu/γ-Fe2O3 @PGE exhibited lower ΔEp (0.191 V), high electrochemical active surface area (ECSA) (0.4620 cm2), higher oxygen evolution potential (OEP) (1.72 V), and lower charge transfer resistance of 9.747 Ω/ cm2 which was ideal for electro-oxidation of AMX. Under the optimum reaction conditions (I = 0.2 mA, pH = 4), the % AMX removal reached 90.5 % after 50 min of electro-oxidation in 0.5 M NaCl. •OH, H2O2, and HOCl were found to be the in-situ generated oxidants. The AMX solution after electro-oxidation did not exhibit antibacterial activity. The toxicity of the formed intermediates were evaluated using Toxicity Estimation Software Tool (T.E.S.T) and found to be less toxic. The electrical energy consumption was estimated to be 0.786 kWhm−3.Thus, modified PGE finds application in the remediation of effluents containing amoxicillin.