Indian Journal of Chemical Technology, Vol.12, No.2, 181-186, 2005
Rubber seed shell carbon as sequestrant of heavy metals and organic compounds from aqueous solution
Powdered activated carbon was prepared from ammonium chloride activated rubber seed shell at 500 degrees C and characterized in terms of pH, bulk density, surface area, abrasion resistance and total surface charge. The sorption behaviour of zinc ions and alcohols (methanol, ethanol and n-propanol) on the shell carbon was studied. The removal efficiency of the metal ions was found to depend upon the initial metal ion concentration, with efficiency decreasing with increase in concentration of the metal ions. By fitting the equilibrium sorption data obtained into the Langmuir isotherm equation, values for maximum metal ions binding capacity and affinity (binding) constant of 0.425 mmol/g and 2.614 respectively were determined. The sorption data also fitted the Freundlich isotherm equation, but with relatively lower correlation coefficient, and values for the coefficient and exponent of the isotherm equation of 0.19 and 0.59 respectively were determined. The removal efficiency of the alcohols was measured in terms of changes in the chemical oxygen demand of solutions containing various volume fractions of the alcohols before and after treatment with the shell carbon. Removal efficiency was generally lower than 30%: and corresponded to about 5.82 mg/L/g decrease in chemical oxygen demand; and was highest for n-propanol and lowest for methanol.