MOE Key Laboratory of New Processing Technology for Non-ferrous Metals and Materials, Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials, School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, PR China.
Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, PR China.
J Environ Manage. 2023 Jan 1;325(Pt B):116424. doi: 10.1016/j.jenvman.2022.116424. Epub 2022 Oct 22.
The effective removal of radioactive strontium (especially Sr) from nuclear wastewater is crucial to environmental safety. Nevertheless, materials with excellent selectivity in Sr removal remain a challenge since the similarity with alkaline earth metal ions in the liquid phase. In this work, a novel titanium phosphate (TiP) aerogel was investigated for Sr(II) removal from the radioactive wastewater based on the sol-gel method and supercritical drying technique. The TiP aerogel has amorphous, three-dimensional and mesoporous structures with abundant phosphate groups, which was confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), atomic force microscope (AFM) and Fourier transform infrared spectroscopy (FT-IR). The adsorbent exhibited high efficiency and selectivity for the removal of Sr(II) with an extensive distribution coefficient up to 4740.03 mL/g. The adsorption equilibrium reached within 10 min and the maximum adsorption capacity was 373.6 mg/g at pH 5. And the kinetics and thermodynamics data fitted well with the pseudo-second-order model and Langmuir model respectively. It can be attributed to the rapid trapping and slow intraparticle diffusion of Sr(II) inside the mesoporous channels of the TiP aerogel. Furthermore, TiP aerogel exhibited over 80% removal for 50 mg/L Sr in real water systems (seawater, lake water and tap water). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy revealed that strong ionic bonding formed during Sr(II) adsorption with the phosphate group on TiP aerogel. These results indicated that TiP aerogel is a promising high-capacity adsorbent for the effective and selective capture of Sr(II) from radioactive wastewater.
有效去除核废水中的放射性锶（尤其是 Sr）对于环境安全至关重要。然而，由于与液相中碱土金属离子的相似性，具有优异 Sr 去除选择性的材料仍然是一个挑战。在这项工作中，我们基于溶胶-凝胶法和超临界干燥技术，研究了一种新型钛磷酸盐（TiP）气凝胶，用于从放射性废水中去除 Sr(II)。TiP 气凝胶具有非晶态、三维和中孔结构，并且含有丰富的磷酸根，这一点通过 X 射线衍射（XRD）、能量色散光谱（EDS）、原子力显微镜（AFM）和傅里叶变换红外光谱（FT-IR）得到了证实。该吸附剂对 Sr(II)的去除具有高效率和选择性，分配系数高达 4740.03 mL/g。吸附平衡在 10 min 内达到，在 pH 5 时的最大吸附容量为 373.6 mg/g。动力学和热力学数据分别与准二级模型和 Langmuir 模型拟合良好。这可以归因于 Sr(II)在 TiP 气凝胶的中孔通道内的快速捕获和缓慢的颗粒内扩散。此外，TiP 气凝胶在实际水系统（海水、湖水和自来水）中对 50 mg/L Sr 的去除率超过 80%。X 射线光电子能谱（XPS）和拉曼光谱表明，在 Sr(II)吸附过程中，TiP 气凝胶上的磷酸根与 Sr(II)形成了强离子键。这些结果表明，TiP 气凝胶是一种很有前途的高效、选择性的大容量吸附剂，可用于从放射性废水中有效去除 Sr(II)。
