Performance evaluation of two chelating ion-exchange sorbents for the fractionation of labile and inert metal species from aquatic media
Performance evaluation of two chelating ion-exchange sorbents for the fractionation of labile and inert metal species from aquatic media
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两种螯合离子交换吸附剂用于从水生介质中分离不稳定和惰性金属物质的性能评估
DOI：
10.1007/s00216-003-2237-y
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发表时间：
2004
影响因子：
4.3
通讯作者：
D. Batistoni
中科院分区：
文献类型：
--
作者：
M. Alvarez;M. E. Malla;D. Batistoni
两个亚氨基二乙酸螯合树脂的性能，应用于元素分馏计划，进行了研究，在潜在污染的港口和工业区收集的海洋和河流水样品的表征。比较涉及的吸附/解吸行为的镉，铜，铅和锌的Chelex-100，吸附剂广泛用于金属形态的研究，并Lewatit TP-207，具有类似的螯合特性的材料，没有应用程序的分馏研究报告的评价。后一种树脂的表征在从水溶液中吸收的金属和随后的酸洗脱的样品pH值的影响方面进行。分馏研究进行天然水样品和模型溶液类似的组合物，加标微摩尔浓度的金属。操作上定义的分馏方案是基于动态吸附的树脂不稳定馏分的金属上的吸附剂制成的微柱。该阶段之后是分批程序，其中来自柱的洗脱液与新鲜树脂接触，以区分在柱相互作用时间期间不能与树脂反应的相对稳定的物质，以及即使在几个小时的时间内也不与吸附剂相互作用的强络合金属。从粗过滤的子样品和通过孔径为0.45和0.22 µm的膜过滤器的样品中获得结果。该方法还用含有不同浓度（在10-3-10-7摩尔范围内）的络合物形成剂如次氮基三乙酸和反式-1，2-二氨基环己烷-N，N，N '，N'-四乙酸的金属的模型溶液进行了评估。一个额外的分批方法，其中固定量的树脂与样品溶液接触增加的时间段，并作为经过的时间的函数测量的溶液中剩余的金属的量，被用来获得在添加的络合剂的存在下形成的物种的解离动力学的信息。两种树脂的行为相似，这表明Chelex-100实验中的物种区分可以通过使用Lewatit TP-207进行的独立分馏测试进行适当验证。吸附剂的行为也讨论了在颗粒或胶体材料的可能影响和动力学效应相关的络合剂的存在下。
The performance of two iminodiacetate chelating resins, applied in an element fractionation scheme, was investigated for the characterization of marine and stream water samples collected in potentially contaminated harbor and industrial zones. The comparison involved an evaluation of the sorption/desorption behavior of Cd, Cu, Pb and Zn on Chelex-100, a sorbent extensively employed for metal speciation studies, and on Lewatit TP-207, a material with similar chelating characteristics for which no applications for fractionation studies are reported. A characterization of the latter resin in terms of the influence of sample pH on the uptake of metals from aqueous solutions and their subsequent acid elution was carried out. Fractionation studies were performed on natural water samples and model solutions resembling their composition, spiked with micromolar concentrations of the metals. The operationally defined fractionation scheme is based on dynamic adsorption of the resin-labile fractions of metals on microcolumns made of the sorbents. This stage is followed by a batch procedure in which the eluent from the column is contacted with fresh resin to discriminate between the relatively stable species unable to react with the resin during the column interaction time, and the strongly complexed metals that do not interact with the sorbent even for periods of several hours. Results were obtained from coarsely filtered sub-samples and from specimens passed through membrane filters of pore size 0.45 and 0.22 µm. The method was also assessed with model solutions of the metals containing variable concentrations (in the 10-3–10-7 molar range) of complex forming agents such as nitrilotriacetic acid and trans-1,2-diaminocyclohexane-N,N,N’,N’-tetraacetic acid. An additional batch method, in which a fixed amount of resin was contacted with sample solution for increasing periods of time and the amount of metal remaining in solution measured as a function of the elapsed time, was used to obtain information on the kinetics of dissociation of species formed in the presence of added complexants. The behavior of both resins was similar, demonstrating that the discrimination of species derived from experiments with Chelex-100 may be properly validated by independent fractionation tests carried out with Lewatit TP-207. The behavior of the sorbents is also discussed in terms of the possible influence of particulate or colloidal materials and of kinetic effects related to the presence of complexing agents.