The absorption of carbon dioxide accompanied by first order reaction into potassium carbonate-bicarbonate buffer solutions, containing sodium hypochlorite as the catalyst, was used to evaluate liquid film mass transfer coefficients and effective interfacial areas in a screen（60 mesh） disc packing column and a smoothed face metallic disc packing columm, respectively. The residence time distributions using a tracer pulse input-response technique were measured to find the extent of mixing of liquid on the disc packings.
It was found that liquid film mass transfer coefficients, effective interfacial areas and the holdup of liquid for both packings increased with increase of liquid wetting rate, that the effective interfacial areas depended on the holdup of liquid, and that the holdup of liquid and the extent of liquid mixing on the screen disc packing increased 1.8 and 1.5 times as high as that on the metallic disc packing, respectively.