Chiang Mai Journal of Science

In this study, the potential of biosorption of heavy metal ions by corncob and the natural fungi growing on corncob was investigated. Solutions containing lead (II) and copper (II) ions were prepared synthetically in single component and the time required for attaining biosorption equilibrium was studied. The effects of initial pH of heavy metal ions solutions and biosorbent dosages in respective ranges of 4.0 to 6.0 and 150 to 350 g (wet weight) on adsorption efficiency were also examined.Results showed the equilibrium time for biosorption of lead and copper ions from the solution to be approximately 90 minutes. The optimum initial pH for lead and copper adsorption by the natural fungi growing on corncob was 5.0. Under these conditions, the biosorption of lead and copper ions solution was 4.29 and 1.76 mg metal/g dry biomass, respectively. When using corncob alone as control, the corresponding values for the biosorption of lead and copper were 1.09 and 0.67 mg metal/g dry biomass, respectively, at initial pH level of 5. The adsorption equilibrium data were adequately characterized by both Langmuir and Freundlich equations. The maximum adsorption capacity based on the Langmuir isotherm, was found to be 14.75 and 1.77 mg metal per g dry weight biosorbent for lead and copper adsorption, respectively, at initial pH level of 5.0 by the natural fungi growing on corncob.