Axs d8 discover gadds x ray diffractometer

Experiments for XRD characterization were conducted using the FeEC and ACAIE experimental setups described in sections 2.1.1 and 2.1.2, but a simple electrolyte (5 mM NaCl, 5 mM NaHCO 3 , pH 7) was Manuscript accepted on April 20, 2020 for publication in Environmental Science and Technology. DOI: 10.1021/acs.est.0c00012 used instead of SBGW. We used the simple electrolyte, which was free of surface-poisoning oxyanions, to ensure that the solids formed were crystalline enough for adequate characterization by XRD. For this analysis, we focused primarily on distinguishing between pure Fe(III) precipitates and mixed-valent Fe(II-III) (hydr)oxides. Fe precipitates for XRD measurements were collected on a 0.1 µm filter using a vacuum pump. Fe(II-III) (hydr)oxide samples were collected under nitrogen atmosphere and a small amount (~1mL) of glycerol was added to the filtered solids to prevent Fe(II) oxidation by exposure to air. 35 Diffractograms were collected from 5 to 95 2θ with a Bruker AXS D8 Discover GADDS X-ray diffractometer, using Co K- radiation. To facilitate comparison among samples with different crystallinity, we report the diffractograms normalized by the highest intensity peak.