1.0 m naoh

Fe(OH) 2 (s) Synthesis. A detailed synthesis procedure for Fe(OH) 2 (s) and product characterization may be found in previously published work. 18 Briefly, Fe(OH) 2 (s) was prepared and stored inside an anoxic chamber (Coy Laboratories) that was maintained using a gas mix of N 2 (98%) and H 2 (2%). Fe(II)Cl 2 •4H 2 O (14 g, >95%, Fisher Scientific) was dissolved in N 2 -purged double deionized water (400 g, DDI, Millipore 18Ω). Dissolved Fe(II) was then precipitated as Fe(OH) 2 (s) by adding 8.2 mL of 10 M NaOH (Fisher Scientific) to solution and mixing by hand. The solid was allowed to react overnight and then separated from the supernatant using a 0.45 µm Nalgene® filter. The Fe(OH) 2 (s) was then allowed to dry for 24 hours before it was powdered using a mortar and pestle. Simulant Preparation. A 5 M Na Hanford LAW simulant with 1080 ppm Cr(VI) was generated as described previously, 17 and spiked with 1-100 ppm Tc(VII), using a 10,000 mg/L Tc stock solution (NH 4 TcO 4 ). The starting simulant was characterized using ion chromatography (IC) and inductively coupled plasma optical emission spectrometry (ICP-OES) (Table 1).