Demulsification and Oil Removal from Metalworking Fluids by Polyurethane Foam as Sorbent

In this study polyurethane foam (p-PUF) was applied in tests of demulsification of metalworking fluids. The results showed the strong influence of the media pH on the oil adsorption. FTIR deconvolution elucidated that the acid media could improve the availability of urethane groups to participate of demulsification process. Results also showed that the foam has a maximum oil adsorption capacity of 541 mg g(-1)at pH 6 the turbidity removal from metalworking fluids by p-PUF was of 86% while at pH lower than 4, turbidity removal was higher than 99%. The demulsification process happens because of two types of interaction: hydrophobic and electrostatic. The Freundlich model showed a better fit to the experimental data and MDSP error of 1.5. p-PUF was used even five times without losing its sorption capacity. [GRAPHICS] .

Automated summary

The study demonstrated the significant influence of media pH on the demulsification of metalworking fluids using polyurethane foam, with acid media improving the availability of urethane groups. As pH decreased, the foam showed higher turbidity removal rates from the fluids.