Evaluation Method of Emulsion Using Chemical Oxygen Demand

¹ Advanced Course of Material Engineering, National Institute of Technology (KOSEN), Kochi College, 200-1 Monobe Otsu, Nankoku-city, Kochi 783-8508, Japan
² Department of Material Science, National Institute of Technology (KOSEN), Wakayama College, 77 Noshima, Nada-cho, Gobo-city, Wakayama 644-0023, Japan
³ Department of Applied Chemistry and Biochemistry, National Institute of Technology (KOSEN), Wakayama College, 77 Noshima, Nada-cho, Gobo-city, Wakayama 644-0023, Japan
⁴ Department of Social Design Engineering, National Institute of Technology (KOSEN), Kochi College, 200-1 Monobe Otsu, Nankoku-city, Kochi 783-8508, Japan

^* Corresponding author: tada@ge.kochi-ct.ac.jp

Abstract

The “gas–liquid two-phases mixed flow” mechanism that fine bubble generation uses rapidly swirling water, which shear gas and making small bubbles in water. Based on this mechanism, sending liquid such as oil into the swirling water instead of gas and it able to be emulsified. At present, evaluation methods for emulsions are using particle size distribution and dispersion stability. However, the emulsion with bad separation behavior has a problem to catch only some dispersed oil particles and use them as a whole evaluation. In this study we examined emulsion evaluated by chemical oxygen demand (COD) to express numerical evaluation including the oil particles that cannot be dispersed. Using three emulsions of only one oil, an anionic and a nonionic emulsifier were mixed and added to the oil, an anionic and another kind of the nonionic emulsifier were mixed and added to the oil. It was confirmed that COD decreased and type of only one oil was the most evaporate. These results lead to the conclusion that the performance of the emulsion could be expressed numerically, including the oil particles which could not be dispersed. We also directly analyzed evaporate components and compared them with COD results.