Fabrication of recyclable magnetic fluorinated polyether nanocomposites with TiO2–carbon heterostructures for enhanced demulsification performance in oily wastewater treatment

Abstract

Crude oil emulsions are challenging to break due to their complex and variable composition. While high-performance demulsifiers exist, many conventional systems still face limitations such as poor stability under harsh conditions or insufficient separation efficiency for specific emulsion types. It is thus essential to develop new demulsifiers that combine high salt resistance with effective destabilization capability. Carbon materials, known for their strong adsorption capacity and chemical stability, can efficiently capture emulsified droplets, enabling significantly enhanced demulsification performance even under harsh conditions. The integration of TiO₂–carbon heterostructures with fluorinated polyether grafting into magnetic demulsifiers represents a previously unreported strategy. Building on this background, our research innovatively modified the magnetic substrate Fe₃O₄ by incorporating TiO₂ and three types of carbon materials (carbon nanospheres, graphene oxide, and carbon nanotubes). Through a sol–gel approach, fluorinated polyether chains were covalently grafted onto the surface of modified Fe₃O₄ nanoparticles, leading to the successful synthesis of three novel magnetic composite demulsifiers: Fe₃O₄@Ti/C–F, Fe₃O₄@Ti/G–F and Fe₃O₄@Ti/CN–F. The results demonstrate that these three demulsifiers exhibit excellent demulsification efficiency, acid resistance, and excellent recyclability. They achieve demulsification rates exceeding 85% in neutral and acidic environments. Notably, Fe₃O₄@Ti/G–F stands out with the best performance. After five cycles of recovery from a biphasic system, its demulsification efficiency remains above 70%. When used at a concentration of 600 mg L⁻¹, it can achieve a demulsification rate of 93.44% within just 30 minutes. In summary, this innovative magnetic nanodemulsifier not only provides an efficient and stable solution for crude oil emulsion separation but also offers significant ecological benefits, holding great potential for application in the treatment of oily wastewater.