An electrolytic CO2-removal device for anion analysis of a liquid sample. The device includes a basic chamber and CO2-permeable tubing in the basic chamber. Anion exchange membranes are disposed on opposite sides of the basic chamber, and electrodes are disposed outside the membranes. The device can be integral with a suppressor in an ion chromatography system and/or an aqueous stream purifier. Also, methods performed by the device.