Ex vivo applications of human carbonic anhydrase II (HCA II) for its potential in CO2 capture technologies are emerging owing to the formidably large hydration turnover number Nature endowed this enzyme with to catalyze aqueous hydration of CO2 near diffusion limits. An innovative scrubbing concept is proposed and simulated with a multiscale (channel-washcoat-resin bead) model to analyze the performances of a new gas-liquid-solid monolith slurry reactor for CO2 catalytic hydration with immobilized (washcoat) HCA II and in-situ bicarbonate removal by ion exchange beads (slurry). The function of in-situ ion-exchange for HCO3- removal is to reduce product inhibition and to enhance CO2 hydration rate. Simulation of CO2 scrubbing for monolith three-phase slurry enzymatic reactor in postcombustion capture enabled assessing the role of enzyme loading, channel washcoat thickness, resin concentration, buffer acid-base constant and concentration, fluid fluxes, gas composition and channel length. By enabling resin exchange-removal of inhibitor, reactor performances are improved with increasing enzyme loading, and buffer concentration and acid-base constant. (C) 2011 Elsevier B.V. All rights reserved.