The optimal conditions for preparation of rambutan peel based activated carbon (RPAC) for removal of Remazol Brilliant Blue R (RBBR) reactive dye from aqueous solution were investigated. The RPAC was prepared using physiochemical activation method which consisted of potassium hydroxide (KOH) treatment and carbon dioxide (CO2) gasification. The central composite design (CCD) was used to determine the effects of the preparation variable, activation temperature, activation time and KOH impregnation ratio on RBBR percentage removal and RPAC yield. Two quadratic models were developed to correlate the preparation variables for both responses. The significant factors on each experimental design response were identified from the analysis of variance (ANOVA). The optimum conditions for RPAC preparation were obtained by using activation temperature of 789 degrees C, activation time of 1.8h and IR of 3.5, which resulted in 78.38% of RBBR removal and 18.02% of RPAC yield. (C) 2011 Elsevier B.V. All rights reserved.