Novel Precipitated Zirconia-Based DGT Technique for High-Resolution Imaging of Oxyanions in Waters and Sediments
| Autor: | Paul N. Williams, Huacheng Xu, Jun Luo, Jian Lun Zheng, Chao Cai, Lena Q. Ma, Dong-Xing Guan |
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| Rok vydání: | 2015 |
| Předmět: |
Anions
Geologic Sediments Time Factors Materials science Analytical chemistry Oxyanion Environment Diffusion Ferrihydrite chemistry.chemical_compound Imaging Three-Dimensional Chemical Precipitation Environmental Chemistry Cubic zirconia Precipitation (chemistry) Spectrophotometry Atomic Osmolar Concentration Water Sorption General Chemistry Hydrogen-Ion Concentration Diffusive gradients in thin films Oxygen Kinetics chemistry Zirconium Particle size Gels Layer (electronics) Water Pollutants Chemical |
| Zdroj: | Environmental Science & Technology. 49:3653-3661 |
| ISSN: | 1520-5851 0013-936X |
| Popis: | Water-sediment exchange is a fundamental component of oxyanion cycling in the environment. Yet, many of the (im)mobilization processes overlay complex spatial and temporal redox regimes that occur within millimeters of the interface. Only a few methods exist that can reliably capture these porewater fluxes, with the most popular being high-resolution diffusive gradients in thin films (HR-DGT). However, functionality of HR-DGT is restricted by the availability of suitable analyte binding agents within the sampler, which must be simple to cast and homogeneously distributed in the binding layer, exhibit adequate sorption capacities, be resistive to chemical change, and possess a very fine particle size (≤10 μm). A novel binding layer was synthesized to meet these requirements by in situ precipitation of zirconia into a precast hydrogel. The particle diameter≤0.2 μm of zirconia in this precipitated gel was uniform and at least 50-times smaller than the conventional molding approach. Further, this gel had superior binding and stability characteristics compared with the commonly used ferrihydrite HR-DGT technique and could be easily fabricated as an ultrathin gel (60 μm) for simultaneous oxygen imaging in conjunction with planar-optodes. Chemical imaging of anion and oxygen fluxes using the new sampler were evaluated on Lake Taihu sediments. |
| Databáze: | OpenAIRE |
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