Arundo donax L. as a low-cost and promising biosorbent for the removal of crystal violet from aqueous media: kinetic, isotherm and thermodynamic investigations

In the present study, Arundo donax L was used as a low-cost biosorbent for the uptake of basic dye crystal violet (CV) from aqueous media. Systematic batch mode studies of adsorption of crystal violet (CV) on Arundo donax were carried out as a function of process of parameters includes initial CV concentration, dose of adsorbent, pH, contact time and temperature. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D-R) isotherm models. The adsorption of CV followed the Langmuir model with a maximum adsorption capacity (qmax) of ۱۹.۶۰ mg/g and pseudo second-order kinetics under a specified set of conditions. The thermodynamic parameters like free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) changes for the adsorption of CV ions have been evaluated and it has been found that the reaction was spontaneous and exothermic in nature. Owing to its rapid adsorption rate and uptake capacity, stem of Arundo donax L. seems to be a promising biosorbent for removal of toxic dyes from wastewater.

Keywords:

Adsorption , Crystal violet , Isotherms , Kinetics , Thermodynamics