(1. 東華理工大學(xué) 核資源與環(huán)境省部共建國家重點(diǎn)實(shí)驗(yàn)室培育基地，南昌 330013；
2. 中國原子能科學(xué)研究院，北京 102413)
摘 要: 以微波輔助KMnO4改性玉米芯為吸附劑來吸附溶液中的U(Ⅵ)，探討改性玉米芯吸附溶液中U(Ⅵ)的熱力學(xué)特征。結(jié)果表明：隨著溫度的升高，改性玉米芯對(duì)U(Ⅵ)的吸附量增大。Langmuir模型能更好地反映吸附過程特征，說明吸附主要發(fā)生在改性玉米芯表面的活性區(qū)域，屬于單分子層吸附。吸附熱力學(xué)參數(shù)ΔG、ΔH和ΔS的計(jì)算結(jié)果表明，所有溫度下ΔG在 U(Ⅵ)初始濃度≤80 mg/L時(shí)均為負(fù)值，且溫度越高ΔG值越負(fù)，表明改性玉米芯對(duì)U(Ⅵ)的吸附過程是一個(gè)自發(fā)的過程，且溫度越高，自發(fā)程度越大。焓變?chǔ)和熵變?chǔ)都為正值，說明吸附過程吸熱，溫度越高，越有利于吸附的進(jìn)行。
關(guān)鍵字: 高錳酸鉀；玉米芯；鈾；吸附；熱力學(xué)特征
（1. State Key Laboratory Breeding Base of Nuclear Resources and Environment, East China Institute of Technology,
Nanchang 330013, China;
2. China Institute of Atomic Energy, Beijing 102）
Abstract:The corncob modified by KMnO4 in microwave was used for the adsorption of U(Ⅵ) ions from aqueous solution, and the thermodynamic characteristics on the adsorption were discussed. The results show that the adsorption capacity of the modified corncob increases with increasing temperature. Langmuir and Freundlich isotherms were used to fit the adsorption equilibrium data, and it is found that the adsorption process follows preferably the Langmuir isotherm adsorption model, which indicates that the adsorption mainly occurs in active region on the surface of modified corncob and belongs to the monolayer adsorption. The thermodynamic parameters, such as Gibbs free energy ΔG, enthalpy ΔH and entropy ΔS changes for the adsorption of U(Ⅵ) were calculated and discussed. When the concentration of U(Ⅵ) is below 80 mg/L, the Gibbs free energies of adsorption at all temperatures are negative and decrease with increasing temperature, which indicates that the adsorption process is spontaneous and the higher the temperature is, the greater the degree of spontaneous is. The entropy change ΔS and enthalpy change ΔH are positive, so the adsorption process is a heat absorption, the higher the temperature is, the more beneficial to adsorption is.
Key words: potassium permanganate; corncob; uranium; adsorption; thermodynamic characteristics
