Abstract: The bubble-to-emulsion mass transfer at non-isothermal conditions is investigated via a coupled computational fluid dynamics-discrete element method (CFD-DEM) approach. The application of CFD-DEM approach in mass exchange prediction is verified. Meanwhile, mass transfer behaviors for an isolated bubble at different injection temperatures are analyzed. It is found that the non-uniform gas concentration is significantly influenced by the uneven temperature inside the bubble besides the impact of flow patterns. Furthermore, the effects of bubble interaction and coalescence on mass transfer are discussed. Two bubbles are injected through the same orifice or two horizontally separated orifices. It is observed that the mass transfer process for two vertically separated bubbles is greatly enhanced in the final period owing to the powerful “suction effect” from the upper bubble. Whereas the mass transfer becomes weak when two bubbles are horizontally injected.