Sacrificial anode Fered–Fenton process for the degradation of a model naphthenic acid in high‐salinity water

Abstract Offshore oilfield produced water (OPW) is a highly complex and hypersaline effluent from oil and gas extraction industry. Since the water‐soluble organic (WSO) compounds in its composition are challenging to be eliminated, their treatment by various advanced oxidation processes (AOP) have been proposed. Among these, Fenton‐like processes have shown promising results in the degradation of recalcitrant organic pollutants present in OPW. Nevertheless, most of the studies have not considered the high salinity of OPW from offshore production units. Therefore, this study investigates a sacrificial anode Fered–Fenton (EF‐Fered) process to degrade a persistent naphthenic acid cyclohexane carboxylic acid (CHA), as a WSO model contaminant, in hypersaline synthetic OPW (100 g L −1 NaCl). The simultaneous effect of homogeneous Fenton oxidation and in‐situ electrogenerated active chlorine and ferryl‐oxo species was systematically evaluated under varying operational conditions (current density, H 2 O 2 concentration, pH, and temperature). Results revealed that acidic conditions (pH 3) are strictly required to maximize removal efficiency, circumventing the chloride scavenging effect through favourable iron speciation and HOCl generation. Under optimal conditions, the EF‐Fered system achieved 88% removal of CHA in 30 min, significantly outperforming conventional Fenton oxidation (51%). Despite operating under oxidant‐saturated regimes at higher current densities, the sacrificial anode configuration demonstrated remarkable robustness with H 2 O 2 supplementation. These findings propose a highly efficient and easily scalable electrochemical strategy to overcome the salinity barrier in the treatment of highly soluble organic pollutants in OPW.