Pure CO₂ was absorbed by de-ionized water using membranes with different porosities in a flat sheet membrane contactor. When the liquid was kept static, the porosity had little effect on the absorption process. When the liquid was stirred, the mass transfer process was enhanced. However, the porosity influenced the mass transfer process due to the uneven distribution of the concentration profile of the solute near the membrane surface. In order to improve the distribution of the concentration of the solute near the membrane surface, solid particles were added to the absorbent liquid in order to enhance the turbulence in the boundary layer. The movement of the particles in the liquid boundary layer resulted in the concentration profile near the membrane surface on the liquid side becoming more homogeneous. Consequently adding the solid particles to the absorbent liquid resulted in a decrease in the differences in mass transfer coefficients obtained for various porosities and the mass transfer efficiency was raised above 40%. The highest enhancement factors were obtained for low porosities. The enhancement effect initially became more significant with increasing concentration of the solid, and then remained constant with further increases in solid concentration. The enhancement factor decreased with increasing stirring speed. 