（英）二氧化钛/石墨烯复合材料对水溶液中钯离子的吸附性能研究

本文合成了一种新型二氧化钛/石墨烯(TiO2-Gr)复合材料吸附剂,研究了其对水溶液中Pd(II)的吸附作用,并与TiO2的吸附性能进行了比较。制得的TiO2-Gr吸附剂分别进行了透射电子显微镜(TEM)表征及X射线衍射(XRD)分析,考察了吸附过程中时间、溶液p H、吸附剂用量、离子强度、Pd(II)浓度和温度等参数对吸附量的影响。研究了吸附过程中动力学、热力学及吸附等温线。结果表明吸附过程符合假二级动力学模型,吸附等温线符合Langmuir和Freundlich等温吸附方程。对热力学函数(吉布斯函数变、焓变、熵变)测定表明,本文合成的TiO2-Gr吸附剂对Pd(II)的吸附属于自发吸热反应。

Adsorption of Palladium with TiO2-graphene Composites from Aqueous Solutions

In the present work, TiO₂-graphene (TiO₂-GN) composites were synthesized and employed as a new adsorbent for the adsorption of Pd(II) from an aqueous solution. The prepared TiO₂-GN composites were characterized with transmission electron microscope (TEM) and X-ray diffraction (XRD). The adsorption behaviors of Pd(II) on TiO₂-GN were compared with those on TiO₂. Parameters affecting the adsorption of Pd(II), such as contact time, sample pH, adsorbent amount, ion strength, Pd(II) concentration, and temperature, were studied in detail. The adsorption kinetics investigations illustrated that the adsorption rate of Pd(II) on TiO₂-GN could be described by the pseudo-second-order model. Langmuir and Freundlich isotherm models were used to express the adsorption data, indicating that both models matched the experimental data well. Thermodynamic functions, the changes of Gibbs free energy (?G°), enthalpy (?H°), and entropy (?S°), were also determined. Results showed that the adsorption of Pd(II) on TiO₂-GN was a spontaneous and endothermic reaction.