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首页> 外文期刊>Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine >Effects of low molecular weight organic acids on (137)Cs release from contaminated soils.
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Effects of low molecular weight organic acids on (137)Cs release from contaminated soils.

机译：低分子量有机酸对（137）Cs从污染土壤中释放的影响。

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摘要

Radio pollutant removal is one of several priority restoration strategies for the environment. This study assessed the effect of low molecular weight organic acid on the lability and mechanisms for release of (137)Cs from contaminated soils. The amount of (137)Cs radioactivity released from contaminated soils reacting with 0.02 M low molecular weight organic acids (LMWOAs) specifically acetic, succinic, oxalic, tartaric, and citric acid over 48 h were 265, 370, 760, 850, and 1002 Bq kg(-1), respectively. The kinetic results indicate that (137)Cs exhibits a two-step parabolic diffusion equation and a good linear relationship, indicating that the parabolic diffusion equation describes the data quite well, as shown by low p and high r(2) values. The fast stage, which was found to occur within a short period of time (0.083-3 h), corresponds to the interaction of LMWOAs with the surface of clay minerals; meanwhile, during the slow stage, which occurs over a much longer time period (3-24 h), desorption primarily is attributed to inter-particle or intra-particle diffusion. After a fifth renewal of the LMWOAs, the total levels of (137)Cs radioactivity released by acetic, succinic, oxalic, tartaric, and citric acid were equivalent to 390, 520, 3949, 2061, and 4422 Bq kg(-1) soil, respectively. H(+) can protonate the hydroxyl groups and oxygen atoms at the broken edges or surfaces of the minerals, thereby weakening Fe-O and Al-O bonds. After protonation of H(+), organic ligands can attack the OH and OH(2) groups in the minerals easily, to form complexes with surface structure cations, such as Al and Fe. The amounts of (137)Cs released from contaminated soil treated with LMWOAs were substantially increased, indicating that the LMWOAs excreted by the roots of plants play a critical role in (137)Cs release.
机译：清除无线电污染物是环境的几种优先恢复策略之一。这项研究评估了低分子量有机酸对从污染土壤中释放（137）Cs的不稳定性和机理的影响。与0.02 M低分子量有机酸（LMWOA）特别是乙酸，琥珀酸，草酸，酒石酸和柠檬酸反应的受污染土壤释放的（137）Cs放射性在48小时内为265、370、760、850和1002 Bq kg（-1）分别。动力学结果表明（137）Cs表现出两步抛物线扩散方程和良好的线性关系，表明抛物线扩散方程很好地描述了数据，如低p和高r（2）值所示。快阶段，发现在短时间内（0.083-3小时）发生，对应于LMWOA与粘土矿物表面的相互作用。同时，在较长的时间段（3-24小时）内的缓慢阶段，解吸主要归因于颗粒间或颗粒内扩散。 LMWOAs进行第五次更新后，乙酸，琥珀酸，草酸，酒石酸和柠檬酸释放的（137）Cs放射性总量相当于390、520、3949、2061和4422 Bq kg（-1）土壤， 分别。 H（+）可使质子的断裂边缘或表面的羟基和氧原子质子化，从而削弱Fe-O和Al-O键。 H（+）的质子化后，有机配体可以轻松地攻击矿物中的OH和OH（2）基团，与表面结构阳离子（例如Al和Fe）形成配合物。从LMWOAs处理过的污染土壤中释放的（137）Cs数量大大增加，表明植物根部分泌的LMWOAs在（137）Cs释放中起关键作用。

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