Factorial design of experiments in the determination of adsorption equilibrium constants for basic methylene blue using biopolymer

Equilibrium conditions in the adsorption of a basic dye on Chitosan were st udied. The Factorial Design methods and Analysis of Variance have been appl ied in the experimental determination of adsorption equilibrium constants. Factorial design with three levels of temperature (30 degrees C, 45 degrees C, 60 degrees C), pH (6.7, 8.1, 9.5), particle size (0.177 mm, 0.914 mm, 1 .651 mm) was used in identification of significant effects and interactions in the calculation of the equilibrium constants. The dye adsorption capaci ty of chitosan was found to increase by decreasing the particle size and in creasing temperature and pH. The methodology identifies the principal exper imental variables, which have the greatest effect on the adsorption process .