One of the major problems of the oil industry is the formation of water-in-oil (W/O) emulsions during the various stages of crude oil production and refining. These types of emulsions cause several problems, the most important of which are damage to refinery equipment, reduction in the quality and quantity of crude oil and environmental pollution. In the current study, Fe₃O₄@ ethylene oxide–propylene oxide copolymer decorated graphene oxides and Fe₃O₄@ ethylene oxide–propylene oxide copolymer decorated multi-walled carbon nanotubes (MCNTs) were considered for the demulsification of W/O emulsions. Effects of three independent variables such as saline, pH, and demulsifier dosage were investigated for the separation of W/O emulsion. According to the experimental results, the best settling time using Fe₃O₄@ ethylene oxide–propylene oxide copolymer @CNTs is at pH of 2, 0.5 gm of salt content, and dose of 100 mg/L, while for Fe₃O₄@ ethylene oxide–propylene oxide copolymer @ graphene oxide, the best conditions are at pH of 6, 3.5 gm of salt content, and dose of 350 mg/L. The results revealed that the needed settling time was considerably less than the traditional chemical demulsifier.