Br掺杂纳米多孔TiO_2的制备及其吸附性能

Preparation and adsorption property of Br-doped nano porous TiO_2

以钛酸四丁酯为钛源,NH4Br为溴源,应用水热技术制备Br掺杂纳米多孔TiO2材料(Br/TiO2)。利用X射线衍射仪和场发射扫描电镜表征材料的结构和形貌,并从热力学和动力学角度研究Br/TiO2对阳离子蓝X-GRL的吸附行为。结果表明:Br掺杂有利于形成棒状交联的多孔结构,增强TiO2对阳离子蓝X-GRL的吸附性能,吸附效率为92.2%,是空白样品的1.56倍。动力学研究表明:该吸附行为符合准二级动力学模型,测得其表观活化能为14.551 kJ/mol,说明该吸附属于物理吸附。热力学研究表明:Br/TiO2对阳离子蓝X-GRL吸附自由能变为8.343-5.600 kJ/mol,吸附熵变为137.10 J/(K.mol),吸附焓变为33.773 kJ/mol,该吸附过程是一个自发的吸热过程。

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 TiO2nanorods,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 ΔGΘare 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.