Study of Cd (II) ions biosorption from aqueous solution by wheat bran

Abstract

Biosorption Wheat bran Cadmium ion Aqueous solution Thermodynamic parametersWheat bran without any chemical treatment was used as biosorbent for sorption of cadmium ions from aqueous solution.The structure of biosorbent was characterized by ATR-IR spectra and pH of the point zero charge (pHPZC).The effect of initial metal concentration, biosorbent dose, contact time, temperature, initial solution, pH, on biosorption of Cd(II) ion from aqueous solution into wheat bran were determined.The best results were achieved at contact time 30 min at pH 5.5 and temperature 25 o C. We used Freundlich and Langmuir isotherms to characterize the adsorption equilibrium.The biosorption of cadmium ions fits well with the Langmuir and Freundlich isotherms, according to experimental data (R 2 0.996 and R 2 0.995, respectively).The maximum biosorption capacity of cadmium ions with the Langmuir model for wheat bran is qmax= 6.25 mg/g, at optimal conditions.Thermodynamic parameters (ΔH o , ΔS o and ΔG o ) showed that the exothermic, spontaneous and favourable biosorption process.These results predict that wheat bran can be used for uptake of cadmium ions from aqueous solution.