title: Novel precipitated zirconia-based DGT technique for high-resolution imaging of oxyanions in waters and sediments.
abstract: 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.
authors: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China.
authors: Dong-Xing
authors: DX
authors: Guan
authors: ‡Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, United Kingdom.
authors: Paul N
authors: PN
authors: Williams
authors: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China.
authors: Jun
authors: J
authors: Luo
authors: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China.
authors: Jian-Lun
authors: JL
authors: Zheng
authors: §State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors: Hua-Cheng
authors: HC
authors: Xu
authors: ∥Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors: Chao
authors: C
authors: Cai
authors: †State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China.|⊥Soil and Water Science Department, University of Florida, Gainesville, Florida 32611, United States.
authors: Lena Q
authors: LQ
authors: Ma
mesh_terms: D000838:Anions / Q000032:analysis*; D011232:Chemical Precipitation; D004058:Diffusion; D004777:Environment; D005782:Gels; D019015:Geologic Sediments / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D021621:Imaging, Three-Dimensional; D007700:Kinetics; D009994:Osmolar Concentration; D010100:Oxygen / Q000032:analysis*; D013054:Spectrophotometry, Atomic; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000838:Anions; D005782:Gels; D014874:Water Pollutants, Chemical; D014867:Water; D015040:Zirconium; C028541:zirconium oxide; D010100:Oxygen