Though water-soluble cutting oil is an essential material for metal-cutting processes, its release into the water system prompts significant contaminations. Since the emulsion of water and oil cannot be completely separated, it is difficult to recycle and often designated as waste for incineration.

To solve this problem, I developed a more effective demulsifier using pine powder with a lignin content of more than 50%.

When pine powder and sulfuric acid were added to 5% water-soluble cutting oil, the emulsion removal effect was confirmed. At first, the process took 3 weeks at room temperature, but it was later reduced to 1 hour at 80℃. To identify the demulsifying component of pine powder, I conducted an experiment using pine extract, confirming that lignin is a demulsifying component.

Then, by comparing calcium lignosulfonate to sodium lignosulfonate, I confirmed that both substances had a high demulsifying effect, yet calcium lignosulfonate showed a greater demulsification performance. As such, I confirmed that treating 200 ml of water-soluble cutting oil emulsion with 0.016 g of calcium lignosulfonate and sulfuric acid (0.048 M) removes emulsion by nearly 100%.

Also, I used the activated carbons to completely eliminate the yellow colorings from the separated water layer. Lastly, I applied this demulsification method to the waste cutting fluids, and the separation of emulsion was successful, highlighting its potential application to real-life settings.

Moreover, I performed a bottle test using calcium lignosulfonate on the artificial emulsion made by combining crude oil and surfactant (Tween 20). The lignosulfonate showed a superior demulsifying effect compared to the control group, signifying that my demulsification method can be used not only for purifying water-soluble cutting oil but also as a demulsifier in various fields, including the crude oil industry.

In another project, I used decomposed pine tree powder to create an environmental oil absorbent. I researched about the environmental harms of using water-soluble cutting oils and tested the potential of pine tree powder for separating the artificial emulsion of oil and water.