Zhang D, Liu X Y, Zhao H T, Yang L, Lü T, Jin M Q
College of Materials and Environmental Engineering, Hangzhou Dianzi University Hangzhou Zhejiang 310018 China
College of Environmental & Resource Sciences, Zhejiang University Hangzhou Zhejiang 310058 China.
RSC Adv. 2018 Jun 8;8(38):21084-21091. doi: 10.1039/c8ra04013c.
Radioactive iodine is quite mobile in soil and poses threats to human health and the ecosystem. Many materials, including layered double hydroxides (LDH), have been synthesized to successfully capture iodine from aqueous environments. However, limited information is available on the application of LDH in soil to immobilize iodine species. In the present study, the feasibility of using Mg-Al-NO LDH for retention of soil iodate (IO ) in both batch and column systems was analyzed. The 2 : 1 Mg-Al-NO LDH exhibited the greatest removal efficiency of IO from aqueous solution, compared with 3 : 1 and 4 : 1 Mg-Al-NO LDH. The Mg-Al-NO LDH demonstrated a strong affinity for IO , with a high sorption capacity of 149 528 mg kg and a Freundlich affinity constant of 21 380 L kg. The addition of Mg-Al-NO LDH in soil resulted in significant retention of IO in both the batch and column experiments. The affinity parameter of soil with the addition of 1.33% Mg-Al-NO LDH was 136 L kg, which was 28.6 times higher than soil without LDH added. Moreover, the eluted iodate percentage was only 12.9% in the soil column with the 1.33% Mg-Al-NO LDH addition, whereas almost 43.5% iodate was washed out in the soil column without LDH addition. The results suggested that Mg-Al-NO LDH could effectively immobilize iodate in soil without obvious interference.
放射性碘在土壤中具有较强的迁移性，对人类健康和生态系统构成威胁。人们已合成了许多材料，包括层状双氢氧化物（LDH），以成功地从水环境中捕获碘。然而，关于LDH在土壤中固定碘形态的应用研究较少。本研究分析了Mg-Al-NO LDH在批次和柱系统中保留土壤中碘酸盐（IO₃⁻）的可行性。与3:1和4:1的Mg-Al-NO LDH相比，2:1的Mg-Al-NO LDH对水溶液中IO₃⁻的去除效率最高。Mg-Al-NO LDH对IO₃⁻表现出很强的亲和力，吸附容量高达149528 mg/kg，弗伦德利希亲和常数Kf为21380 L/kg。在土壤中添加Mg-Al-NO LDH后，批次和柱实验中IO₃⁻均有显著保留。添加1.33% Mg-Al-NO LDH的土壤的亲和参数Kf为136 L/kg，比未添加LDH的土壤高28.6倍。此外，在添加1.33% Mg-Al-NO LDH的土壤柱中，洗脱的碘酸盐百分比仅为12.9%，而在未添加LDH的土壤柱中，几乎43.5%的碘酸盐被洗脱。结果表明，Mg-Al-NO LDH能有效固定土壤中的碘酸盐，且无明显干扰。
