Dong Zhen, Du Jifu, Chen Yanliang, Zhang Manman, Zhao Long
State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electric and Electronic Engineering, Huazhong University of Science and Technology, 430074, Wuhan, China.
School of Nuclear Technology and Chemistry & Biology, Hubei University of Science and Technology, Xianning, 437100, China.
Environ Pollut. 2021 Jan 5;273:116432. doi: 10.1016/j.envpol.2021.116432.
Ammonium molybdophosphate (AMP) exhibits high selectivity towards Cs but it cannot be directly applied in column packing, so it is necessary to prepare AMP-based adsorbents into an available form to improve its practicality. This work provided two AMP immobilized cellulose microspheres (MCC@AMP and MCC-g-AMP) as adsorbents for Cs removal by radiation grafting technique. MCC-g-AMP was prepared by radiation graft polymerization of GMA on microcrystalline cellulose microspheres (MCC) followed by reaction with AMP suspension, and MCC@AMP was synthesized by radiation hybrid grafting of AMP and GMA onto MCC through one step. The different structures and morphologies of two adsorbents were characterized by FTIR and SEM. The adsorption properties of two adsorbents against Cs were investigated and compared in batch and column experiments under different conditions. Both adsorbents were better obeyed pseudo-second-order kinetic model and Langmuir model. MCC-g-AMP presented faster adsorption kinetic and more stable structure, whereas MCC@AMP presented more facile synthesis and higher adsorption capacity. MCC@AMP was pH independent in the range of pH 1-12 but MCC-g-AMP was sensitive to pH for Cs removal. The saturated column adsorption capacities of MCC@AMP and MCC-g-AMP were 5.4 g-Cs/L-ad and 0.75 g-Cs/L-ad in column adsorption experiments at SV 10 h. Both adsorbents exhibited very high radiation stability and can maintain an adsorption capacity of >85% even after 1000 kGy γ-irradiation. On the basis, two AMP-loaded adsorbents possessed promising application in removal of Cs from actual contaminated groundwater. These findings provided two efficient adsorbents for treatment of Cs in radioactive waste disposal.
钼酸铵磷酸盐（AMP）对铯具有高选择性，但它不能直接用于柱填充，因此有必要将基于AMP的吸附剂制备成可用形式以提高其实用性。本工作提供了两种AMP固定化纤维素微球（MCC@AMP和MCC-g-AMP）作为通过辐射接枝技术去除铯的吸附剂。MCC-g-AMP是通过甲基丙烯酸缩水甘油酯（GMA）在微晶纤维素微球（MCC）上进行辐射接枝聚合，然后与AMP悬浮液反应制备的，而MCC@AMP是通过一步将AMP和GMA辐射杂化接枝到MCC上合成的。通过傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）对两种吸附剂的不同结构和形态进行了表征。在不同条件下的分批和柱实验中研究并比较了两种吸附剂对铯的吸附性能。两种吸附剂均较好地符合准二级动力学模型和朗缪尔模型。MCC-g-AMP呈现出更快的吸附动力学和更稳定的结构，而MCC@AMP呈现出更简便的合成方法和更高的吸附容量。MCC@AMP在pH 1-12范围内对pH不敏感，但MCC-g-AMP对去除铯的pH敏感。在空床接触时间（SV）为10 h的柱吸附实验中，MCC@AMP和MCC-g-AMP的饱和柱吸附容量分别为5.4 g-Cs/L-吸附剂和0.75 g-Cs/L-吸附剂。两种吸附剂均表现出非常高的辐射稳定性，即使在1000 kGy γ辐照后仍能保持>85%的吸附容量。在此基础上，两种负载AMP的吸附剂在从实际受污染地下水中去除铯方面具有广阔的应用前景。这些发现为放射性废物处置中铯的处理提供了两种高效吸附剂。
