Research
| Title： | A novel Mg(OH)(2) binding layer-based DGT technique for measuring phosphorus in water and sediment |
|---|---|
| First author： | Xie, Fazhi; Li, Lu; Sun, Xiaoyan; Hu, Tingting; Song, Kang; Giesy, John P. P.; Wang, Qilin |
| Journal： | ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS |
| Years： | 2020 |
| DOI： | 10.1039/c9em00508k |
| Abstract： | Diffusive gradients in thin films (DGT) have gained wide attention for in situ measurement of reactive phosphorus species (PO4) in natural water, sediments and potentially soils. In this study, a novel Mg(OH)(2) binding gel was formed using magnesium hydroxide obtained by in situ hydration of calcined magnesium oxide. Laboratory scale experiments showed that the novel Mg(OH)(2) gel had a homogeneous dispersion of fine particles of Mg(OH)(2) with a particle size of 2-5 mu m. With 10 mL of 2.0 mol L-1 NaOH as the eluting agent, the optimal elution efficiency of PO4 on the Mg(OH)(2) gel was 72 +/- 5%. There were linear relationships between the accumulated PO4 mass and the applied PO4 concentration (0.1 to 20 mg P per L), time (0 to 24 h) and temperature (22 to 40 degrees C). The capacity of the Mg(OH)(2) binding layer was determined to be 99.5 mu g P per disc. Tests in synthetic seawater, Chaohu Lake and Yihai Pond confirmed that Mg(OH)(2)-DGT was able to accurately measure phosphorus up to 10 days. This was indicated by the good agreements between the concentrations measured by DGT (C-DGT) technology and by an ex situ chemical method in solution (C-soln), with a C-DGT/C-soln ratio between 0.91 and 1.09. |
