在本研究中,以Purolite S930Plus 螯合樹脂為固體吸附劑,吸附水溶液中的重金屬鎘(Ⅱ)和鎳(Ⅱ)。藉由改變金屬濃度、樹脂克數及操作溫度並觀察溶液pH值的變化,探討其吸附特性。 研究顯示,鎘(Ⅱ)、鎳(Ⅱ)的單成分溶液系統的吸附平衡時間大約分別在600分鐘、960分鐘,而鎘(Ⅱ)與鎳(Ⅱ)共存的雙成分溶液系統的吸附平衡時間大約在1440分鐘;在鎘(Ⅱ)與鎳(Ⅱ)金屬共存的雙成分溶液系統下,發現樹脂對鎳(Ⅱ)的選擇性高於鎘(Ⅱ)。而平衡吸附量則隨著溶液溫度上升而增加,但是平衡吸附量卻隨著溶液中樹脂克數增加而降低。金屬平衡後的數據以Freundlich、Langmuir 、BET等溫模式比較下,實驗結果顯示符合Freundlich等溫模式。此外也由金屬離子吸附結果求得熱力學參數中的焓(ΔH°)、自由能(ΔG°)、熵(ΔS°)值。 在單成份系統Cd2+:ΔH°= 8824∼11089(J/mol),ΔG°= -5226∼-7432 (J/mol),ΔS°= 20.36∼57.65 (J/mol.K)。 在單成份系統Ni2+:ΔH°=5125∼13405(J/mol),ΔG°= -5790∼-9773 (J/mol),ΔS°= 39.98∼68.06(J/mol.K)。 在雙成份系統中Cd2+:ΔH°=13100∼13314(J/mol),ΔG°= -5741∼-8013(J/mol),ΔS°=21.24∼73.31(J/mol.K)。 在雙成份系統中Ni2+:ΔH°=9454∼11961(J/mol) ,ΔG°= -5972∼-11066(J/mol),ΔS°=54.02∼69.45(J/mol.K)。
In this study, we examined the adsorption characteristics of Cadmium(II) and Nickel(II) onto Purolite S930Plus from aqueous solution in respect to changes in metal concentration, resin gram and temperature of the reaction environment, while changes in pH value of solutions were observed. The study showed that the lengths of time to achieve adsorption balance for the Cadmium(II) single composition solution system and the Nickel(II) single composition solution system are 600 minutes and 960 minutes respectively, whereas for the binary composition solution system of Cadmium(II) and Nickel(II), it is 1440 minutes. In the binary composition solution system, the selectivity of resin toward Nickel(II) is higher than its selectivity for Cadmium(II). The adsorption amount per resin gram increased as the temperature of the reaction environment rose, but decreased along with rises in resin grams. The results also showed that for the adsorption of both metals, the Freundlich isotherm model fitted the equilibrium data best, compared with the Langmuir isotherm and the BET isotherm models. In addition, we also calculated the thermodynamic functions, enthalpy (ΔH°), free energy (ΔG°), and entropy (ΔS°) changes of adsorption for each metal ion. Single system(Cd2+):ΔH°= 8824∼11089(J/mol),ΔG°= -5226∼-7432 (J/mol),ΔS°= 20.36∼57.65 (J/mol.K). Single system(Ni2+):ΔH°=5125∼13405(J/mol),ΔG°= -5790∼-9773 (J/mol),ΔS°= 39.98∼68.06(J/mol.K). Binary system(Cd2+):ΔH°=13100∼13314(J/mol),ΔG°= -5741∼-8013(J/mol),ΔS°=21.24∼73.31(J/mol.K). Binary system(Ni2+):ΔH°=9454∼11961(J/mol),ΔG°= -5972∼-11066(J/mol),ΔS°=54.02∼69.45(J/mol.K).