context: 5.3.2 Coexisting substrates and contaminants. The investigated substrates and contaminants for oily water separation were mainly strong electrolytes such as NaCl, HCl and NaOH. Considering these coexisting chemicals would not significantly change the surface properties of titanate, the added electrolytes were found to have no apparent effects for oil/water separation.
answer: NaCl, HCl and NaOH