MODIFIED HARDWICKIA-BINATA BARK FOR ADSORPTION OF MERCURY (II) FROM WATER

Hardwickia binata bark was found to have a good sorption capacity for mercury (II). Colour leaching can be prevented and the physical characteristics of the bark can be improved by treatment with formaldehyde in acidic medium. Studies indicated that the sorption of Hg(II) increases as the pH increases and a contact time of 2 h was found to be optimum. The effect of concentration shows that modified bark can remove most of the Hg(II) from water if its concentration is below 20 mg/l and sorption of mercury conformed to the Freundlich adsorption isotherm. The presence of light metal ions interferes with the sorption of mercury. Mg(II) at a concentration of 200 mg/l interferes with sorption to a maximum extent. Among the different anions, it was observed that sorption of mercury was maximum for acetate and nitrate (97%). The break-through sorption capacity determined by conducting a column experiment was observed to be 21 mg/g. © 1990.