Decolorization and regeneration of waste lubricating oil by a CNTs/PDMS/PVDF membrane

The utilization of waste industrial lubricating oil can save energy and protect the environment. In this work, an experimental study had been conducted to solve the decolorization problem, and the properties of the regenerated oil were compared with waste lubricating oil and fresh oil. CNTs/PDMS/PVDF membranes were prepared for the regeneration of waste lubricating oil, and the optimum mass ratio of PDMS/PVDF was 1:5 with 1.0 wt % carbon nanotubes. The transmittance, kinematic viscosity, condensation point and water content were measured, and the friction properties and recovery were tested. The results showed that the transmittance of regenerated oil can be increased to 94.93%, and the kinematic viscosity was close to that of fresh oil. The water content decreased from 77.7 ppm to 32.4 ppm, lower than 52.6 ppm of fresh oil. The condensation point decreased from –25°C to –27°C, which was close to –30°C of fresh oil. The wear scar diameter decreased from 0638 mm to 0.552 mm, and the friction coefficient decreased from 0.088 to 0.074. The oil recovery rate can be up to 94.60%.