Cattail leaves as a novel biosorbent for the removal of malachite green from liquid phase: data analysis by non-linear technique

The ability of cattail (Typha angustifolia) leaves (CL) for the biosorption of malachite green (MG), a cationic dye, from aqueous solutions was investigated. Biosorption isotherm and kinetics of MG by CL were studied through a number of batch sorption experiments. The influence of operating conditions such as initial dye concentration, biosorbent dose, initial pH, stirring speed, temperature, ionic strength and biosorbent particle size on the removal of MG was investigated. Equilibrium data were fitted to the Langmuir, Freundlich, Redlich–Peterson and Sips isotherm models using non-linear regression technique. Experimental equilibrium data were best represented by the Redlich–Peterson and Sips isotherms, but the Redlich–Peterson model was better. Biosorption kinetics obtained at different initial concentrations were analysed using pseudo-first-order, pseudo-second-order and pseudo-nth order equations. The pseudo-nth order model fit the kinetic data well and was best than the pseudo-first- and pseudo-second-order equations. The order of biosorption reaction n was found to be between 1.27 and 1.93. The results revealed that the CL has the potential to be used as a biosorbent for the removal of MG from aqueous solutions.