(江蘇大學(xué) 化學(xué)化工學(xué)院，鎮(zhèn)江 212013)
摘 要: 以鈦酸四丁酯為鈦源，NH4Br為溴源，應(yīng)用水熱技術(shù)制備Br摻雜納米多孔TiO2材料(Br/TiO2)。利用X射線衍射儀和場發(fā)射掃描電鏡表征材料的結(jié)構(gòu)和形貌，并從熱力學(xué)和動力學(xué)角度研究Br/TiO2對陽離子藍(lán)X-GRL的吸附行為。結(jié)果表明：Br摻雜有利于形成棒狀交聯(lián)的多孔結(jié)構(gòu)，增強(qiáng)TiO2對陽離子藍(lán)X-GRL的吸附性能，吸附效率為92.2%，是空白樣品的1.56倍。動力學(xué)研究表明：該吸附行為符合準(zhǔn)二級動力學(xué)模型，測得其表觀活化能為14.551 kJ/mol，說明該吸附屬于物理吸附。熱力學(xué)研究表明：Br/TiO2對陽離子藍(lán)X-GRL吸附自由能變?yōu)?#8722;8.343~−5.600 kJ/mol，吸附熵變?yōu)?37.10 J/(K∙mol)，吸附焓變?yōu)?3.773 kJ/mol，該吸附過程是一個(gè)自發(fā)的吸熱過程。
關(guān)鍵字: Br摻雜；二氧化鈦；納米多孔材料；吸附動力學(xué)；吸附熱力學(xué)
（School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, China）
Abstract:Br-doped TiO2 nano porous materials (Br/TiO2) were prepared using NH4Br as the bromine precursor and tetrabutylorthotitanate as Ti source by the hydrothermal method. The structure and morphology of the prepared sample were characterized by X-ray diffraction (XRD) and field-emission scanning electronmicroscopy (FE-SEM). The kinetic and thermodynamic parameters for the absorption of cationic blue X-GRL in aqueous solution by Br/TiO2 were studied．The results show that Br doping favors to form the nano porous network structure composed of TiO2 nanorods, which helps to the absorption property of cationic blue X-GRL. The adsorption efficiency of Br/TiO2 is 92.2%, which is the 1.56 times of bare TiO2. The kinetics study results show that the pseudo-second-order kinetic model is well described for the adsorption of Br/TiO2 for cationic blue X-GRL. And the apparent activation energy is determined to be 14.551 kJ/mol. The thermodynamics study results show that the values of ΔGΘ are in the range of −8.343~−5.600 kJ/mol, and the values of ΔHΘ and ΔSΘ are 33.773 kJ/mol and 137.10 J/(K∙mol), respectively. So, the adsorption process is endothermic and spontaneous.
Key words: Br doping; TiO2; nanoporous material; adsorption kinetics; adsorption thermodynamics
