Kim, S.W.;Lim, J.L.

  • Published : 2007.02.28


Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.


Adsorption;Herb residue;Heavy metal;Pre-treatment;Korean medicine


  1. Al-Asheh, S., and Duvnjak, Z., 'Sorption of cadmium and other heavy metals by pine bark,' J. Hazard. Mater., 56, 35-51 (1997)
  2. Al-Asheh, S., Banat, F., Al-Omari, R., and Duvnjak, Z., 'Prediction of binary sorption isothermsfor the sorption of heavy metals by pine bark using single isotherm data,' Chemosphere, 41, 659-665 (2000)
  3. Brown, P. A., Gill, S. A., and Allen, S. J., 'Metal removel from wastewater using peat,' Water Res., 34, 3907-3916 (2000)
  4. Brown, P., Jefcoat, I. A., Parrish, D., Gill, S., and Graham, E., 'Evaluation of the adsorptive capacity of peanut hull pellets for heavy metals in solution,' Adv. Environ. Res., 4, 19-29 (2000)
  5. Burns, C. A., Cass, P. J., Harding, I. H., and Grawford, R. J., 'Adsorption of aqueous heavy metals onto carbonaceous substrates,' Colloid. Surf. A: Physicochem. and Eng. Asp., 155, 63-68 (1999)
  6. Kumar, A., Rao, N. N., and Kaul, S. N., 'Alkali-treated straw and insoluble straw xanthate as low cost adsorbents for heavy metal removal-preparation, characterization and application,' Bioresour. Technol., 71, 133-142 (2000)
  7. Mohan, D., and Chander, S., 'Single component and multi-component adsorption of metal ions by activated carbons,' Colloid. Surf. A: Physicochem. Eng. Asp., 177, 183-196 (2001)
  8. Mohan, D., and Singh, K. P., 'Single- and multi-component adsorption of cadmium and zinc using activated carbon derived from bagasse-and agricultural waste,' Water Res., 36, 2304-2318 (2002)
  9. Ricordel, S., Taha, S., Cisse, I., and Dorange, G., 'Heavy metals removal by adsorption onto peanut husks carbon : Characterization, kinetic study and modeling,' Sep. Purif. Tech., 24, 389-401 (2001)
  10. Yu, B., Zhang, Y., Shuka, A., Shukla, S. S., and Dorris, K. L., 'The removal of heavy metals from aqueous solutions by sawdust adsorption-removal of lead and comparison of its adsorption with copper,' J. Hazard. Mater., B84, 83-94 (2001)
  11. Rhee, In H., 'Binary and ternary cation exchanges: The effect of electrolyte anions on selectivity and adsorption capacity,' Environ. Eng. Res., 4(3), 195-206 (1999)
  12. Borge, G, Arana, G., Fernandez, L. A., and Madariaga, J. M., 'Determination of ion exchangs equilibrium constants of strongly acidic resins with alkaline-earth metals by means of the potentiometric titrations technique,' Talanta, 48, 91-102 (1999)