Under the same total alkalinity, the absorbing rate of the regenerated spent caustic liquid (or mass transfer factor) is directly related with the OH concentration.

The correlations of the packing factor of pressure drop, packing factor of flooding point, and HTU of the true liquid phase mass transfer were obtained.

It was shown that average pore size of membrane, which determined the mechanisms of mass transfer through the membrane, was the substantial factor of the membrane separation characteristics.