The Use of Corn cob Micro Powder as a Low Cost Adsorbent, for the Removal of Co2+Ion from Aqueous Solutions and from the View Point Thermodynamics

Abstract

Corn cob as a low cost adsorbent was used in the present work for the removal of toxic heavy metal Co2+ from aqueous solutions. Bath experiments were used to determine the best adsorption conditions. The equilibrium adsorption level was determined as a function of solution pH, temperature (T), contact time (tc), initial adsorbate concentration, and adsorbent dosage. Effective removal of metal ions was demonstrated at pH values of 8. Metal adsorption onto corn cob was evaluated by Langmuir and Freundlich isotherms. Results indicate that the Langmuir isotherm model is the most suitable one for the adsorption process using corn cob (R2=0.9503), thus, indicating the applicability of monolayer coverage of Co+2 ion on corn cob surface. The relationship between thermodynamic parameters was used to predict the absorption process. According to Thermodynamic analysis, the process was found to be endothermic and natural: (ΔHo= -18.7 J mol-1 and ΔSo = -47.6 J mol-1 K-1).<br /> Keywords: Cobalt (II); Adsorption; Thermodynamic; Corn cob