The Freundlich isotherm model was also used to fit the experimental
data for the adsorption of lac dye on cotton at pH
3.0. Linear plots of ln qe versus ln Ce showed that the adsorption
follows the Freundlich isotherm model well with high correlation
coefficients (R2O0.99) (Table 1). The value of Qf has
been used as a relative measure of adsorption capacity, and it
was found that Qf increased with decreasing temperature
which again indicated that the process was exothermic. In
addition, the n values greater than 1 indicated the favourable
adsorption condition.