| Abstract |
| Calcium-rich dolomite was calcined at high temperature to increase heavy metal removal capacity. Dolomite calcined at 900℃ (D900) was shown to obtain highest adsorption amount of heavy metal ( Cd2+, Cu2+, Pb2+, Ni2+). Kinetic, equilibrium, and thermodynamic adsorption was performed to characterize the heavy metal adsorption onto D900. Heavy metals adsorption onto D900 reached equilibrium within 3 hours. The maximum adsorption amounts of Cd2+, Cu2+, and Ni2+ onto D900 were 466.51 mg/g, 566.33 mg/g and 567.84 mg/g, respectively. Freundlich model was more suitable for describing equilibrium adsorption of heavy metals onto D900 than Langmuir model. Thermodynamic analysis showed that the heavy metal adsorption onto D900 is endothermic and spontaneous reaction. The increase of ionic strength of solution influenced negatively on heavy metals ( Cd2+, Cu2+, Pb2+, Ni2+) adsorption. As the dosing amount of D900 increased, the removal percentage of Cd2+ and Ni2+ remained constant but the amount of heavy metal adsorption onto unit mass of D900 was decreased. The increase of D900 dose increased the removal percentage of Cu2+ and Pb2+ but decreased its amount of Cu2+ and Pb2+ adsorption onto unit mass of D900. It can be concluded that D900 can be used as an efficient adsorbent for the removal of heavy metals from aqueous solution. |
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| Key Words |
| Adsorption, Dolomite, Heavy metal, Ionic strength, Thermal treatment |
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