Ejectors are gas-liquid contactors that are reported to provide higher mass transfer rates than conventional contactors. Detailed experiments were performed, and Computational Fluid Dynamics (CFD) modeling studies were undertaken to understand the mass transfer characteristics of the ejector geometry. The mass transfer coefficient and interfacial area were predicted from the volume averaged energy dissipation rate. Studies show that there is an optimum ratio of nozzle area to throat area (area ratio), at which the liquid entrainment rate is the highest. Using optimized geometry can lead to substantial economic benefit in the industrial practice.