Technical University of Crete, Laboratory of Analytical and Environmental Chemistry, University Campus, GR-73100 Chania, Greece.
Technical University of Crete, Laboratory of Analytical and Environmental Chemistry, University Campus, GR-73100 Chania, Greece; Public Power Corporation (PPC) Renewables S.A., Attica, Greece.
Sci Total Environ. 2019 Dec 20;697:134099. doi: 10.1016/j.scitotenv.2019.134099. Epub 2019 Aug 24.
Solid-state Hg(II) selective membranes were produced and assessed by means of X-ray absorption near edge structure in the total reflection X-ray fluorescence (TXRF-XANES) setup and by the energy dispersive X-ray fluorescence (EDXRF) technique. Membranes were functionalized using four promising ligands for mercury complexation, i.e.: i) 4-(2-Pyridylazo) resorcinol (PAR), ii) thiourea, iii) calconcarboxylic acid (CCS), and iv) dithizone. A simple analytical procedure was followed, using miniscule reagent quantities, thus suggesting the process is also cost-effective. TXRF-XANES revealed that mercury complexes with the ligands, and is not simply adsorbed onto the PVC matrix, while the complexation was found to not be affected by the matrix existence. Mercury exhibited an increased oxidation grade and was covalently bound to the ligand functional groups, via a strong chemical bond. EDXRF revealed that the solid-state membranes can be used for mercury speciation and trace analysis from environmentally relevant matrices, such as tap water. The membranes could be a promising alternative to polymer inclusion membranes (PIMs), due to their simple configuration and high Hg (II) selectivity in aqueous media, but more research is needed. PAR appears to be the most promising ligand, followed by dithizone and thiourea. CCS had a minuscule preconcentration efficiency since it was preferably bound with Cu in tap water, indicating limited usefulness for mercury preconcentration. However, results suggest that, depending on the ligand, the solid-state membranes could be also possibly used for multi-elemental heavy metals analysis in water.
采用全反射 X 射线荧光（TXRF-XANES）装置的 X 射线吸收近边结构和能量色散 X 射线荧光（EDXRF）技术，制备并评估了固态 Hg(II) 选择膜。该膜通过四种有前景的汞络合配体进行功能化，即：i）4-(2-吡啶偶氮)间苯二酚（PAR）、ii）硫脲、iii）钙羧酸（CCS）和 iv）双硫腙。采用微量试剂的简单分析程序，因此该过程也具有成本效益。TXRF-XANES 表明汞与配体形成了配合物，而不是简单地吸附在 PVC 基质上，同时发现配合物的形成不受基质存在的影响。汞的氧化态增加，通过强化学键与配体的官能团共价结合。EDXRF 表明固态膜可用于对环境相关基质（如自来水）中的汞进行形态分析和痕量分析。由于其简单的配置和在水相中的高 Hg(II) 选择性，固态膜可能成为聚合物整体膜（PIMs）的替代品，但需要进一步研究。PAR 似乎是最有前途的配体，其次是双硫腙和硫脲。CCS 的预浓缩效率很小，因为它在自来水中优先与 Cu 结合，表明其在汞预浓缩方面的用途有限。然而，结果表明，根据配体的不同，固态膜也可能用于水中多种重金属元素的分析。
