ABSTRACT This article extends the study of the comparison between linear and nonlinear forms of the two widely used kinetic models, namely, pseudo-first-order and pseudo-second-order, by considering the binary biosorption of the basic dyes methylene blue and safranin onto pretreated rice husk in a batch system. The present investigation showed that nonlinear forms of pseudo-first-order and pseudo-second-order models were more suitable than the linear forms for fitting the experimental data. The sorption process was found to follow the pseudo-second-order kinetics. The results suggest that it is not appropriate to use the linear method in determining the kinetic parameters of a particular kinetic model. The nonlinear method is a better way to obtain the kinetic parameters than the linear method and thus it should be primarily adopted to determine the kinetic parameters.