How to remove oil/grease contaminant from an aqueous solution?

I have a solution of water and calcium nitrate that is contaminated with some sort of heavy petroleum oil, semi-solid at room temperature a bit like petroleum jelly, and a strong odor of very crude refining. I wish to retain the salt solution and discard the oil.


The bulk of the oil has adhered to the walls of the glass beaker but a small percent remains in floating in the solution. What are some typical lab methods that could remove the remaining oil? Would adjusting pH assist the process? Would changing the temperature to solidify or melt the grease, or some cycling of temp?


