The reduction Of CO2 concentration in a gas stream containing 500 ppm Of CO2 by a technique combining chemical absorption with Higee (high gravity) was investigated in this study. Using a 2.0 L aqueous amine-based solution to treat the feed gas with a flow rate which varied from 12.9 to 20.6 L min(-1), piperazine (PZ) was found to be more effective than 2-(2-aminoethylamino) ethanol (AEEA) and monoethanolamine (MEA) for reducing the CO2 concentration to a level below 20 ppm. The effects of temperature, rotating speed, amine solution flow rate, and gas flow rate on the removal efficiency Of CO2 were systematically examined. The results indicated that the proposed compact device could effectively reduce CO2 to a level below 20 ppm, as required by a zinc/air battery, for a long period of time using PZ and its mixture with AEEA and MEA as the absorbents. (c) 2006 Elsevier B.V. All rights reserved.