Reversible adsorption of metalworking fluids （MWFs） on Cu-BTC metal organic framework

Metalworking fluids （MWFs） are classified as hazardous substances. Due to the characteristics of the stable oil-wateremulsions, it requires more costly and complicate treatment techniques to remove oil from spent IVIVVFs. Metal or-ganic frameworks （MOFs） are a porous network material used to remove contaminants From environment. Oneof the most prominent of MOFs is HKUST-I or Cu-BTC. In this study, the Cu-BTCs were prepared by solvothermalmethod in various conditions and used as absorbent for removing oil micelles in MWF emulsion. The particle sizeof all synthesized Cu-BTCs ranged from ≈ 80 to 400 nm. The ability of all synthesized Cu-BTCs to remove oil micellewas greater than 95% in 60 rain, while the capacity of GAC was obtained the result for only 6.8%. The maximumadsorption capacity （qmax） of oil micelles on Cu-BTCs was 1666.7 mg·g^-1. The highest removal capacity of oilmicelles in MWF emulsion is greater than 99% in 24 h by using Cu-BTCs washed with either butanol or ethanol.