Interfacial electro-demulsification of industrial oily wastewater: Challenges from fundamental mechanisms to industrial implementation.

Oily emulsified wastewater contains oils, salts, surfactants, PAHs, and other hazardous compounds, and its high toxicity and emulsion stability challenge conventional treatment technologies. Electrochemical demulsification offers high efficiency, mild operation, and automation potential. This review summarizes the sources, characteristics, discharge standards, and conventional treatment methods of oily emulsified wastewater, and compares three representative electrochemical technologies: electrochemical oxidation, electrocoagulation, and electroflotation. Electrochemical oxidation, electrocoagulation, and electroflotation can achieve removal efficiencies of up to 98.7%, 100.0%, and 94.4%, respectively. Comparatively, electrochemical oxidation is more suitable for degrading refractory organic pollutants, electrocoagulation is effective for destabilizing surfactant-stabilized emulsions, and electroflotation is advantageous for bubble-assisted oil-water separation. Key operational factors, mechanisms, limitations, and future perspectives are discussed to guide the selection and development of electrochemical technologies for industrial oily emulsified wastewater treatment.