(遼寧大學(xué) 化學(xué)學(xué)院，沈陽(yáng) 110036)
摘 要: 研究納米TiO2對(duì)Mo(VI)的吸附過程，考察溶液的pH值、時(shí)間、溫度等因素對(duì)吸附的影響。結(jié)果表明：在pH 1~8范圍內(nèi)，納米TiO2對(duì)Mo(VI)的吸附率均超過99%，吸附于納米TiO2上的Mo(VI)可用2.0 mL的0.1 mol/L NaOH溶液定量洗脫；該吸附過程符合準(zhǔn)二級(jí)反應(yīng)動(dòng)力學(xué)模型，其反應(yīng)的表觀活化能為22.7 kJ/mol，粒子內(nèi)部擴(kuò)散過程是其吸附控制步驟，但液相邊界層向粒子表面的擴(kuò)散過程不能忽略；吸附行為服從Langmuir和D-R等溫模型。在室溫下，納米TiO2對(duì)Mo(VI)的飽和吸附容量為12.74 mg/g，平均吸附能為17.36 kJ/mol；吸附反應(yīng)焓變和熵變均為正值，自由能變?yōu)樨?fù)值，說明該吸附過程為自發(fā)的吸熱過程。
關(guān)鍵字: Mo(VI)；納米TiO2；吸附；動(dòng)力學(xué)；熱力學(xué)
（College of Chemistry, Liaoning University, Shenyang 110036, China）
Abstract:Titanium dioxide nanoparticles were employed for the sorption of Mo(VI) ions from aqueous solution. The process was studied in detail by varying the pH value, sorption time and temperature. The adsorption rate of Mo(VI) by the sorbent is over 99% at pH 1−8. Adsorbed Mo(VI) were desorbed by 2.0 mL of 0.1 mol/L NaOH. The kinetic experimental data properly correlate with the second-order kinetic model. The apparent activation energy is 22.7 kJ/mol. The overall rate process is mainly controlled by the intraparticle diffusion, while the boundary layer resistance cannot be ignored. The sorption data could be well interpreted by the Langmuir and D-R type sorption isotherms. At room temperature, the static saturated adsorption capacity is 12.74 mg/g, and the average sorption energy is 17.36 kJ/mol. The thermodynamic parameters: ΔHΘ＞0, ΔSΘ＞0 and ΔGΘ＜0, which indicates a spontaneous and decalescence adsorption process.
Key words: Mo(VI); nano-TiO2; adsorption; kinetics; thermodynamics
