Activated carbon （AC） derived from waste coconut buttons （CB） was investigated as a suitable adsorbent for the removal of heavy metal ions such as Pb（II）, Hg（II） and Cu（II） from industrial effluents through ...Activated carbon （AC） derived from waste coconut buttons （CB） was investigated as a suitable adsorbent for the removal of heavy metal ions such as Pb（II）, Hg（II） and Cu（II） from industrial effluents through batch adsorption process. The AC was characterized by elemental analysis, fourier transform infrared spectroscopy, X-ray diflraction, scanning electron microscopy, thermal gravimetric and diflerential thermal analysis, surface area analyzer and potentiometric titrations. The eflects of initial metal concentration, contact time, pH and adsorbent dose on the adsorption of metal ions were studied. The adsorbent revealed a good adsorption potential for Pb（II） and Cu（II） at pH 6.0 and for Hg（II） at pH 7.0. The experimental kinetic data were a better fit with pseudo second-order equation rather than pseudo first-order equation. The Freundlich isotherm model was found to be more suitable to represent the experimental equilibrium isotherm results for the three metals than the Langmuir model. The adsorption capacities of the AC decreased in the order： Pb（II） Hg（II） Cu（II）.展开更多
The adsorption characteristics of heavy metals： Cu（Ⅱ）, Pb（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） ions on tourmaline were studied. Adsorption equilibrium was established. The adsorption isotherms of all the four metal ions f...The adsorption characteristics of heavy metals： Cu（Ⅱ）, Pb（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） ions on tourmaline were studied. Adsorption equilibrium was established. The adsorption isotherms of all the four metal ions followed well Langmuir equation. Tourmaline was found to remove heavy metal ions efficiently from aqueous solution with selectivity in the order of Pb（Ⅱ）〉Cu（Ⅱ）〉Cd（Ⅱ）〉Zn（Ⅱ）. The adsorption of metal ions by tourmaline increased with the initial concentration of metal ions increasing in the medium. Tourmaline could also increase pH value of metal solution.The maximum heavy metal ions adsorbed by tourmaline was found to be 78.86, 154.08, 67.25, and 66.67 mg/g for Cu（Ⅱ）, Pb（U）, Zn（Ⅱ） and Cd（U）, respectively. The temperature （25-55℃） had a small effect on the adsorption capacity of tourmaline. Competitive adsorption of Cu（Ⅱ）, Pb（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） ions was also studied. The adsorption capacity of tourmaline for single metal decreased in the order of Pb〉Cu〉Zn 〉Cd and inhibition dominance observed in two metal systems was Pb〉Cu, Pb〉Zn, Pb〉Cd, Cu〉Zn, Cu〉Cd, and Cd〉Zn.展开更多
文摘Activated carbon （AC） derived from waste coconut buttons （CB） was investigated as a suitable adsorbent for the removal of heavy metal ions such as Pb（II）, Hg（II） and Cu（II） from industrial effluents through batch adsorption process. The AC was characterized by elemental analysis, fourier transform infrared spectroscopy, X-ray diflraction, scanning electron microscopy, thermal gravimetric and diflerential thermal analysis, surface area analyzer and potentiometric titrations. The eflects of initial metal concentration, contact time, pH and adsorbent dose on the adsorption of metal ions were studied. The adsorbent revealed a good adsorption potential for Pb（II） and Cu（II） at pH 6.0 and for Hg（II） at pH 7.0. The experimental kinetic data were a better fit with pseudo second-order equation rather than pseudo first-order equation. The Freundlich isotherm model was found to be more suitable to represent the experimental equilibrium isotherm results for the three metals than the Langmuir model. The adsorption capacities of the AC decreased in the order： Pb（II） Hg（II） Cu（II）.
基金The National Basic Research Program (973) of China (No. 2004CB418506-3)the National Natural Science Foundation of China(No. 20477029 )
文摘The adsorption characteristics of heavy metals： Cu（Ⅱ）, Pb（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） ions on tourmaline were studied. Adsorption equilibrium was established. The adsorption isotherms of all the four metal ions followed well Langmuir equation. Tourmaline was found to remove heavy metal ions efficiently from aqueous solution with selectivity in the order of Pb（Ⅱ）〉Cu（Ⅱ）〉Cd（Ⅱ）〉Zn（Ⅱ）. The adsorption of metal ions by tourmaline increased with the initial concentration of metal ions increasing in the medium. Tourmaline could also increase pH value of metal solution.The maximum heavy metal ions adsorbed by tourmaline was found to be 78.86, 154.08, 67.25, and 66.67 mg/g for Cu（Ⅱ）, Pb（U）, Zn（Ⅱ） and Cd（U）, respectively. The temperature （25-55℃） had a small effect on the adsorption capacity of tourmaline. Competitive adsorption of Cu（Ⅱ）, Pb（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） ions was also studied. The adsorption capacity of tourmaline for single metal decreased in the order of Pb〉Cu〉Zn 〉Cd and inhibition dominance observed in two metal systems was Pb〉Cu, Pb〉Zn, Pb〉Cd, Cu〉Zn, Cu〉Cd, and Cd〉Zn.
