Efficient treatment of petroleum refinery wastewater by an induced electro-Fenton process

The induced electrochemical-Fenton (I-EF) process is one of the electrochemical advanced oxidation processes (EAOPs) that has been recently applied to treat various types of wastewaters. In this work, the I-EF process, comprising a graphite/SnO2-Sb2O3 anode, an iron-screen-induced electrode, and an air-diffusion cathode, was used to treat petroleum refinery wastewater. The effects of current density (2-10 mA/cm²), pH (3-7), and the number of screens on the induced electrode (1 and 4) on chemical oxygen demand (COD) removal were investigated. Results showed that increasing pH improved COD removal, whereas increasing current density beyond 3 mA/cm2 reduced it. Increasing the screen number also enhanced the COD removal. The preferred conditions were a current density of 3 mA/cm², pH of 7, and four screens, resulting in a COD removal of 88% within 120 min, which claimed an electrical energy consumption of 0.8575 kWh/m³, confirming the successful application of I-EF in petroleum refinery wastewater treatment under natural pH with minimum sludge generation.