负载氢氧化铁的膨胀石墨吸附剂的除磷

Phosphate Removal of Expanded Graphite Loaded with Ferric Hydroxide

摘要:

成功制备了负载氢氧化铁的膨胀石墨吸附剂(EGFeOH)，其最优制备条件为铁浓度0.26 mol?L-1、浸渍时间100min.通过对EGFeOH等温吸附线和动力学研究，发现EGFeOH更加符合Langmuir等温吸附模型和准二级动力学方程，说明EGFeOH的除磷过程以单分子层的化学吸附为主.通过热力学参数ΔHΘ(＞0)和ΔGΘ(＜0)说明EGFeOH吸附磷过程是自发吸热的，升温在一定程度上会提升EGFeOH的除磷吸附容量.EGFeOH对低浓度含磷水体(5 mg?L-1)有较好的除磷效果.通过吸附过程中溶液pH值变化和傅里叶红外变换光谱(FTIR)等分析手段，联合说明了EGFeOH主要通过离子交换作用和Lewis酸碱相互作用进行吸附除磷.以NaOH为脱附液，实现了对EGFeOH的脱附再生.

Abstract:

The expanded graphite loaded with ferric hydroxide (EGFeOH) is prepared successfully. Its most suitable synthesis conditions are 0.26mol/L of ironic concentration and 100min of immersion time, respectively. The Langmuir model and the pseudo secondorder model are more suitable for well elucidation of the experimental data, indicating that the adsorption of phosphate is a monolayer chemisorption process. The positive ΔHΘ and negative ΔGΘ indicate that the process of phosphorus adsorption onto EGFeOH is spontaneous and endothermic. It is favorable for the phosphorus adsorption with the rising of temperature to some extent. EGFeOH performs excellently for phosphate adsorption in low concentration (5 mg?L-1). The ion exchange and lewis acidbase interactions are manifested to be two main mechanisms for phosphate adsorption of EGFeOH revealed by Fourier transform infrared (FTIR) spectroscopy and change of pH values associated with the adsorption process. The EGFeOH after adsorption is also recovered using sodium hydroxide (NaOH).