Study of Modified Banana Fiber as Adsorbent for Cadmium(II) Ions from Aqueous Solution

Abstract

Raw banana fiber (RBF), acid treated banana fiber (ATBF) from banana stem was evaluated as adsorbent for the elimination Cd 2+ from solution. The Cd 2+ solution of 1000 mg/L concentration was prepared from Cd(NO3)2 and different concentrations were prepared by dilution of stock solution. Effects of adsorbent dose, contact time, temperature, initial metal concentration and pH study were evaluated. Langmuir and Freundlich isotherms were employed to describe adsorption capacity The maximum amounts of cadmium(II) adsorbed (qm), which was evaluated by Langmuir isotherm, were 0.469 mg/g and 5.230 mg/g, and highest R 2 (0.9968, 0.9815,) for raw banana fiber and acid treated banana fiber, respectively. Pseudo-second order kinetics best fitted with R 2 = (0.9457), (0.9571) for raw banana fiber and acid treated banana fiber, respectively. Thermodynamic parameters obtained were ∆G° (-8.268) kJ mol -1 K -1 , ∆H° (-9.874), kJ mol -1 K -1 and ∆S° (-5.152) kJ mol -1 for acid treated banana fiber and spontaneity decreases with increase in temperature in case of raw banana fiber and acid treated banana fiber. This indicates that the system is exothermic. Banana stems possess feasible characteristics for making an adsorbent and acid treated banana fiber is more efficient for removal of Cd 2+ ion from its aqueous solution.