核化学与放射化学2026，Vol.48Issue(4)：420-427,8.DOI:10.7538/hhx.2026.48.04.0420
基于二氧化锰沉淀法的大体积水样中241Am的分析方法
Determination of 241Am in Large Volume Water Samples Based on Manganese Dioxide Precipitation Method
摘要
Abstract
Americium-241(241Am)is an important transuranic nuclide with a half-life of 432.6 years,and is classified as a highly toxic radionuclide.Due to its rapid migration and potential for bioaccumulation along food chains in the environment,241Am poses potential threats to environmental radiation safety and human health.The concentration of 241Am in environmental water samples is extremely low,necessitating the collection of large-volume water samples to enhance detection sensitivity and enable the analysis and measurement of low-level 241Am.Pretreatment of large-volume water samples is a major challenge in chemical separation procedures.In this paper,50 L water samples were used for 241Am measurement,with systematic investigation of key factors such as coprecipitation methods and precipitate carrier amounts.After separation and purification,a suitable method was selected through systematic discussion.Finally,an analytical method for 241Am determination in environmental water samples using alpha spectrometry was established.In the process of water sample pretreatment,tap water samples(50 L)were used to compare the pre-concentration efficiencies of calcium-magnesium co-precipitation and manganese dioxide(MnO2)precipitation were compared,and the MnO2 precipitation method was selected for pre-concentration.Approximately 2.0 g of potassium permanganate(KMnO4)was added to form MnO2 precipitates,thereby enriching Am from the water matrix.In the separation and purification step,extraction chromatography was used to systematically investigate the effects of key parameters(i.e.,loading acidity and elution volume)on the chemical recovery yield.DGA resin was used to adsorb Am from the sample solution under 5-6 mol/L HNO3 conditions,followed by elution with 20 mL of 0.01 mol/L HCl-0.03 mol/L NaNO2 to achieve effective separation of Am from other interfering nuclides.For source preparation after separation and purification,0.1 mol/L(NH4)2SO4 was used as the electrolyte solution,and the pH was adjusted to approximately 2.Electrodeposition was carried out at a current density of 0.65-0.70 A/cm2 for about 60 minutes to prepare the measurement source for alpha spectrometry.Thus,an analytical method for 241Am determination in environmental water samples based on alpha spectrometry was established.The established analytical procedure was validated.The experimental results show that with a 48 h measurement time by alpha spectrometry,the overall chemical recovery yield of 243Am in the procedure is 83.4%,the decontamination factor for 242Pu exceeds 103,and the minimum detectable activity concentration of 241Am is determined to be 9.48×10-6 Bq/L.These results indicate that the established method is accurate and reliable.Finally,the method is applied to analyze 241Am in various environmental water samples,including surface water,groundwater,and river water,for monitoring radiation safety in the aquatic environment,meeting the requirements for routine analysis and monitoring of low-level 241Am in environmental water samples.关键词
241Am/大体积水样/二氧化锰沉淀法/分离纯化/分析测量Key words
241Am/large volume water sample/manganese dioxide precipitation method/separation and purification/analytical measurement分类
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文雯,娄海林,文富平,王绍林,丛日俐,郑一凡,李玉芹,江强,喻正伟..基于二氧化锰沉淀法的大体积水样中241Am的分析方法[J].核化学与放射化学,2026,48(4):420-427,8.基金项目
中核集团集中研发项目(FA2225120002066) （FA2225120002066）
