碱激发粉煤灰对Cs~+的吸附行为

将粉煤灰进行碱激发改性,运用XRD和SEM技术对碱激发粉煤灰进行了表征,通过静态平衡吸附实验研究了碱激发粉煤灰对Cs+的吸附动力学和热力学特性,并对吸附前后的碱激发粉煤灰进行了FTIR分析。表征结果显示,碱激发处理后,粉煤灰的晶相发生了改变,且粉煤灰表面密实的硬壳层被破坏。实验结果表明:在初始Cs+质量浓度为200 mg/L、吸附温度为25℃、溶液pH为10、碱激发粉煤灰投加量为12.0 g/L的条件下,碱激发粉煤灰对Cs+的平衡吸附率可达80%以上,其吸附能力比碱激发前提高了3倍以上;吸附过程可用准二阶动力学方程来描述,并较好地符合Langmuir等温吸附模型;碱激发粉煤灰对Cs+的吸附是吸热过程,且能自发进行;该过程以物理吸附为主,并伴随化学吸附。

Adsorption Behavior of Alkali Activated Fly Ash to Cesium Ions

The fly ash was modified by alkali activation and characterized by XRD and SEM. The adsorption kinetics and thermodynamics characteristics of Cs+ on alkali activated fly ash were investigated through an experiment of static equilibrium adsorption，and the alkali activated fly ash before and after adsorption was analysed by FTIR. The characterization results show that the crystal phase of the alkali activated fly ash is changed，and the hard shell layer on the surface of fly ash is destroyed after alkali activation. The experimental results show that：Under the conditions of initial Cs+ mass concentration 200 mg/L，adsorption temperature 25 ℃，solution pH 10 and alkali activated fly ash dosage is 12.0 g/L，the equilibrium adsorption ratio of Cs+ on the alkali activated fly ash can reach above 80%，which is more than 3 times higher than that on the fly ash before alkali activation；The adsorption is coincident with quasi-second order kinetics equation and fits Langmuir isothermal adsorption model well；The adsorption of Cs+ on alkali activated fly ash is a spontaneous endothermic process，and the main adsorption behavior is physical adsorption accompanied with chemical adsorption.