聚吡咯/凹凸棒纳米复合材料对Cr^(6+)的吸附性能

Chromium(Ⅵ) Adsorption onto Polypyrrole/Attapulgite Nanocomposites

以FeCl3为氧化剂和掺杂剂用原位聚合法制备了聚吡咯/凹凸棒纳米复合材料,用以吸附溶液中高毒性的Cr6+。研究表明,该吸附剂在10min内即可达到吸附平衡,吸附效果优异,同时考察了吸附剂用量、Cr6+的初始浓度和pH值对吸附效果的影响。吸附过程等温线数据符合Langmuir等温吸附方程式,饱和吸附量为48.45mg/g,计算得到的热力学数据ΔH、ΔG、ΔS均为负值,说明该吸附过程是一个放热的自发过程。吸附动力学符合准二级动力学方程,说明吸附过程属于化学吸附反应过程。用傅里叶变换红外光谱和扫描电镜对复合材料的结构进行表征,发现聚吡咯微球包覆在棒状的凹凸棒表面形成纳米复合材料,其红外谱图与聚吡咯基本一致。

Using employed FeCl3 as oxidant and dopant,polypyrrole（PPy）/attapulgite（ATP） nanocomposites were prepared by in situ polymerization to remove high poisonous Cr6＋ions from aqueous solutions.The results indicate that the adsorbent possesses high adsorption speed and can reach the adsorption equilibrium within 10min.Other influencing factors such as adsorbent dose,initial concentration of Cr6＋ and pH value were investigated.Isotherm data fits well to the Langmuir isotherm model.The maximum adsorption capacity for Cr6＋ is 48.45mg/g.The thermodynamic parameters,ΔH,ΔG,ΔS were evaluated.Thermodynamic parameters are all negative which imply that the adsorption process is spontaneous and exothermic.The adsorption process follows pseudo-second-order equation,which indicates the adsorption process is controlled by chemical adsorption mechanism.The composites were characterized by Fourier transform infrared spectra（FT-IR） and scanning electron microscopy（SEM）.The results suggest that surfce of ATP was covered with PPy to form nanocomposites.