Purification of SemiSynthetic Metalworking Fluids by Microfiltration

Since the early 2000s, industries have faced rising costs to acquire, manage, and dispose of metalworking fluids, as well as increased concern about pathogenic bacteria growing in metalworking processes. The need to reduce the impacts of these bacteria prompted ISTC’s Kishore Rajagopalan and colleagues to find a solution that would meet both environmental health and metalworking fluid reuse standards. They discovered that microfiltration was the key to achieving their goal. Using an α-alumina membrane of 0.5 µm pore size, they could effectively remove emulsified tramp oil, which is a common contaminant in metalworking fluid. They also observed a 7-log reduction in bacteria, which should result in a 50–99% reduction in endotoxins.