棕榈油厂倾析渣去除镉(Ⅱ)、铜(Ⅱ)及铅(Ⅱ)的吸附动力学及热力学

棕榈油厂的倾析渣含较高有机物质.可将其用作吸附废水中金属离子吸附剂.倾析渣经105℃干燥后于500℃碳化,以碳化后的倾析渣去除Cd^2＋,Cu^2＋和Pb^2＋.采用热重分析法分析碳化后的倾析渣表明：倾析渣湿度为4%,含挥发物21%、固定碳物23%、灰化物52%.运用朗格缪尔（Langmuir）等温模型和弗罗因德利奇（Freundlich）等温模型分析了含倾析渣1 g/100 mL离子水溶液,结果表明：碳化后的倾析渣对Cd,Cu,Pb的最大吸附量分别为24,23,97 mg/g,且吸附动力学遵循准二级反应动力学模型.测定了热力学参数标准生成焓（ΔH°）、标准熵（ΔS°）、标准自由能（ΔG°）.

Kinetic and Thermodynamic Studies of Cd2+, Cu2+ and Pb2+ Removal byDecanter Cake from Palm Oil Mill

Palm oil mills generate about 4-5 tons of decanter cake for every 100 tons of palm fresh fruit bunch processed. Due to the high organic content,the decanter cake could be converted into adsorbent for the removal of metal ions in waste water. The decanter cake was first dried at 105 ℃ and then carbonized at 500 ℃. The resulting carbonized decanter cake was tested for removing Cd2+,Cu2+ and Pb2+ions. Proximate analysis using thermogravimetry of decanter cake carbonized at 500℃ indicated that the adsorbent contained 4 % moisture,21 % volatiles,23 % fixed carbon,and 52 % ash. Adsorption tests were carried out by mixing 1.0 g of the decanter cake in 100 mL aqueous solution of the various ions. Langmuir and Freundlich isotherm models were used to fitted the isotherm experimental data. The maximum uptakes of Cd,Cu and Pb onto the carbonized decanter cake in this study were estimated to be 24,23,and 97 mg/g respectively. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The rmodynamic parameters including standard enthalpy (ΔH°),standard entropy (ΔS°) and standard free energy (ΔG°) were determined.