The present research is centred upon the application of reverse osmosis to the ultrapurification of aqueous hydrogen peroxide (35%, w/w). Semiconductor Equipment and Materials International (SEMI) organization develops the globally most respected standards to establish the quality requirements for the chemicals used in this sector; one of these standards, SEMI 00 is proposed for hydrogen peroxide. Electronic grade hydrogen peroxide accounts for sub-ppm metallic impurity levels (sub-ppb concentrations are required for the most exigent grades), so various elements present as impurities in technical grade hydrogen peroxide exceed the fixed limits. A preliminary experimental study was carried out with a laboratory-scale facility (flat-sheet membrane unit) with 6 different commercial reverse osmosis membranes in order to choose the most appropriate one for hydrogen peroxide ultrapurification. BE membrane (manufactured by Woongjin Chemical) was selected for further viability study because of its higher permeate flux (1.95 x 10(-5) m(3)/m(2) s at 40 bar) and metal rejections values (ranging from 0.825 for B to 0.961 for Cu). The Kedem-Katchalsky model resulted as the most representative for characterizing the selected membrane behaviour as it achieved a percentage of overall variation explained upper than 94%. (C) 2010 Elsevier B.V. All rights reserved.