磷酸化氧化石墨烯的制备及其对U(Ⅵ)的吸附性能研究

Preparation of Phosphorylated Graphene Oxide and Its Adsorption Performance for U(Ⅵ)

研究了以浓磷酸作功能化试剂,通过原位磷酸化法制备磷酸化氧化石墨烯(PGO)。采用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FT-IR)和拉曼(Raman)光谱仪对所制备材料进行表征,考察了溶液初始pH、接触时间、U(Ⅵ)初始浓度和温度等对所制备材料从水溶液中吸附U(Ⅵ)的影响。结果表明:磷酸官能团被成功引入到氧化石墨烯(GO)中,而且GO结构没有被破坏;PGO吸附U(Ⅵ)的速率很快,90min即达平衡,吸附过程符合准二级动力学模型和Langmuir吸附等温线模型;磷酸化之后,GO最大单层吸附量从249.38mg/g提高到336.70mg/g;在有共存离子存在条件下,PGO对U(Ⅵ)的吸附选择性优于GO。

Using phosphoric acid as a functional reagent, preparation of phosphorylated graphene oxide （PGO） by in-situ phosphorylation was studied. Scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy（FT-IR） and Raman spectroscopy were applied to characterize the graphene oxide （GO） and PGO. Effects of pH, contact time, initial U （Ⅵ） concentration, and temperature on adsorbing U（Ⅵ） of GO and PGO from aqueous solution were investigated. FT-IR and Raman spectroscopic analysis results show that the phosphate group is successfully introduced into graphene oxide （GO）. SEM results show that the GO structure has not been destroyed during phosphorylation. In addition, the kinetic investigation results show that the adsorption of U （Ⅵ） in aqueous solution is very quick and archiving equilibrium at 90 rain, and can be described by pseudosecond order equation. Meanwhile, the adsorption processes of GO and PGO for U （ Ⅵ ） follow the Langmuir model,and the monolayer adsorption capacity of GO increases from 249.38 mg/g to 336.70 mg/g after phosphate groups being introduced into it. PGO is superior to GO for selective adsorption U（Ⅵ） in the simulated nuclear effluent with various co-existing ions.