Comparison of Optimized Isotherm Models and Error\nFunctions for Carbon Dioxide Adsorption on Activated Carbon

Abstract

The adsorption of CO₂ on\ncommercial activated carbon\nWG12 and WG12 modified by ZnCl₂ and KOH was investigated\nusing a high pressure Sievert’s apparatus. The experimental\ndata were analyzed using Langmuir, Freundlich, Sips, Toth, Unilan,\nFtitz–Schlunder, and Redlich–Peterson equations. An\nerror analysis was performed to examine the effect of using different\nerror criteria for the isotherm parameters determination. Five error\nanalysis methods were used: the sum of the squares of errors, the\nhybrid fractional error function, the average relative error, the\nMarquardt’s percent standard deviation, and the sum of the\nabsolute errors. The Sips isotherm provided the best quality of fitting\nfor all the experimental data. Error function analysis found that\nsum of the squares of the errors and hybrid fractional error function\nprovided the best overall results.