SUPPORTING INFORMATION. Effects of Sulfidation, Magnetization, and Oxygenation on Azo Dye Reduction by Zerovalent Iron

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1 SUPPORTING INFORMATION Effects of Sulfidation, Magnetization, and Oxygenation on Azo Dye Reduction by Zerovalent Iron Chunhua Xu 1 *, Bingliang Zhang 1, Yahao Wang 1, Qianqian Shao 1, Weizhi Zhou 1 Dimin Fan 2, Joel Z. Bandstra 3, Zhenqing Shi 4, and Paul G. Tratnyek 5 * 1 School of Environmental Science and Engineering Shandong University, Jinan, Shandong 251, P.R. China 2 U.S. Environmental Protection Agency, Office of Superfund Remediation and Technology Innovation, Arlington, VA 2222 USA 3 School of Sciences, Saint Francis University 117 Evergreen Drive, Loretto, PA 1594 USA 4 School of Environment and Energy South China University of Technology Guangzhou, Guangdong 516, P.R. China 5 Institute of Environmental Health Oregon Health & Science University 3181 SW Sam Jackson Park Road, Portland, OR USA *Corresponding authors: xuchunhua@sdu.edu.cn, Phone: , Fax: tratnyek@ohsu.edu, Phone: , Fax: Environmental Science & Technology 1 October 216 1/1/16 S1

2 Contents The chronology of dye removal using ZVI in aerobic or anaerobic conditions (Figure S1)... S3 Properties of Beijing iron... S4 SEM analysis (Figure S2)... S5 EDS analysis (Figure S3)... S6 XPS spectra of Fe 2p and S 2p (Figure S4)... S7 UV-vis spectra for Orange I removal at different time (Figure S5)... S8 Matrix of time series correlations for experimental parameters (Figure S6)... S9 The major degradation pathway of Orange I (Figure S7)... S1 HPLC-MS analysis of Orange I and its product (Figure S8)... S11 FTIR spectra (Figure S9)... S12 Time series of geochemical properties in Fe/FeS respike experiments (Figure S1)... S13 Dissolved oxygen sag curves for varying levels of Orange I exposure (Figure S11)... S14 Fitting results from global analysis of all dissolved oxygen vs. time data (Figure S12)... S15 Summary of kinetic data at different experimental conditions (Table S1)... S16 Information of Orange I and sulfanilic acid obtained by HPLC-MS (Table S2)... S19 Summary of k obs in the respike experiment (Table S3)... S2 Model parameterization results from global analysis of DO data (Table S4)... S21 References for Supporting Information... S23 1/1/16 S2

3 Aerobic Uncertain Anaerobic Number of Records Year of Publication Figure S1. Chronology of research papers on treatment of dye contaminated water using zerovalent iron. Data compiled from multiple sources (Web of Science, Elsevier Science Direct, ACS Publications). The search term dyes returned mostly azo dyes, but also other dye types (anthraquinone, disperse, indicator, etc.), and all are included. Search terms for zerovalent iron (ZVI, Fe(), etc.) returned some papers that only involved iron oxides, so the latter were removed from the results. The intersection of these sets gave the 162 papers included in Figure S1. This group was then classified by whether the experiments were performed under aerobic or anaerobic conditions by analysis of the abstract and methods sections of each manuscript. It is noteworthy that a significant number of papers were classified as uncertain because they did not provide sufficient information to determine if the conditions were aerobic or anaerobic. Unfortunately, the proportion of papers in this category appears to have increased in the recent years, but this trend is likely to be reversed in the future as appreciation of the effects of oxygenation becomes more widespread. 1/1/16 S3

4 Properties of Beijing Iron The zerovalent iron used in this study was obtained from Beijing Enviro-Chem Environmental Technology Co., Ltd. (Beijing, P.R. China). It was selected because it has been used in recent, field-scale applications of ZVI for groundwater remediation in China. This material is manufactured by water atomization, ground with a Raymond mill, and annealed under H 2. The resulting product has nominal purity = 9% and d 5 = 3.1 µm. We further characterized this material by scanning electron microscopy (SEM) with energydispersive X-ray spectroscopy (EDS). The native material (Figure S2A) consists of irregular, roughly-spherical ~2 µm discrete particles, similar to the morphology that has been reported previously for ZVI prepared by the water atomization process. 1 The EDS on this sample detected only Fe and O (Figure S3A). The specific surface area measured by BET N 2 gas adsorption was.342 m 2 /g. After 3 min exposure of this ZVI to the reaction medium (containing Orange I) with WMF, the particle surfaces showed pitting and increased roughness (Figure S2B), C and N were detected on the iron surface by EDS (Figure S3B). Sulfidation of the ZVI increased the surface roughness and S become evident in the EDS (Figure S2C, Figure S4E), both of which are consistent with deposition of a fresh layer of iron sulfides, and the SSA increased to 2.17 m 2 /g. This is similar to what has been seen in other studies of ZVI sulfidation. 2, 3 Exposure of sulfidated ZVI to the reaction medium caused less-uniform surface features to form and left both C, N, and S on the surface (Figure S2D, Figure S3D). 1/1/16 S4

5 Figure S2. SEM analysis for ZVI from this study. (A) untreated Fe/FeO, (B) Fe/FeO after 3 min exposure to medium + Orange I, with WMF, (C) freshly prepared Fe/FeS, (D) Fe/FeS after 3 min exposure to medium + Orange I, without WMF. 1/1/16 S5

6 Figure S3. EDS analysis for ZVI from this study. (A) untreated Fe/FeO, (B) Fe/FeO after 3 min exposure to medium + Orange I, with WMF, (C) freshly prepared Fe/FeS, (D) Fe/FeS after 3 min exposure to medium + Orange I, without WMF. 1/1/16 S6

7 Counts (s) 16 x FeOOH Fe 2p 1/2 Fe 2p3/2 Fe(II)-O Fe /FeS FeOOH Fe(II)-O Fe /FeS Counts (s) 35 x FeOOH Satellite Fe 2p 1/2 Fe 2p 3/2 Fe 2 O 3 Satellite FeOOH Fe 2 O 3 Counts(s) 4 x FeOOH Satellite Fe 2p 1/2 Fe 2p 3/2 Fe 2 O 3 Satellite FeOOH Fe 2 O A (Fe/FeS, min) B (Fe/FeS, 3 min) Fe /FeS 15 1 C (Fe/FeS, 12 min) Binding Energy (ev) Binding Energy (ev) Binding Energy (ev) Counts (s) 16 x Satellite Fe 2p 3/2 Fe 2p 1/2 Fe 2 O FeOOH 3 Fe 2 O 3 FeOOH Satellite Counts (s) S 2 2- (bulk) S 2 2- (surf) S 2p S 2-6 D (Fe/FeO, min) 3 E (Fe/FeS, min-s) Binding Energy (ev) Binding Energy (ev) Figure S4. Fe 2p (A-D) and S 2p (E) XPS spectra for ZVI from this study. (A) Fe/FeS min, (B) Fe/FeS after reaction 3 min without WMF, (C) Fe/FeS after reaction 12 min without WMF, (D) Fe/FeO min, (E) Fe/FeS min. Conditions: ph = 7, Orange I C = 1 mg/l, Fe/FeS = 2 g/l, RPM = 4, T = 25 C. 1/1/16 S7

8 1.2 (A) Fe/FeO -WMF 1.2 (B) Fe/FeO +WMF Absorbance min 1 min 3 min 5 min 1 min 15 min 3 min 6 min 9 min 12 min 476 nm Absorbance nm min 1 min 2 min 3 min 4 min 5 min 7 min 1 min 15 min 3 min 6 min 9 min 12 min 476 nm Wavelength (nm) Wavelength (nm) 1.2 (C) Fe/FeS -WMF 1.2 (D) Fe/FeS +WMF Absorbance nm min 1min 2 min 3 min 5 min 7 min 1 min 15 min 2 min 3 min 6 min 9 min 12 min 476 nm Absorbance nm min 1 min 2 min 3 min 5 min 1 min 15 min 3 min 6 min 9 min 12 min 476 nm Wavelength (nm) Wavelength (nm) Figure S5. UV-vis spectra for Orange I removal using Fe/FeO and Fe/FeS with and without WMF. All data were obtained from stirred, open batch reactors with ph = 7, Orange I C = 1 mg/l, Fe/FeO or Fe/FeS = 2 g/l, RPM = 4, T = 25 C. 1/1/16 S8

9 1. A 1. B 1. C C/C.6.4 Fe/FeO -WMF Fe/FeO +WMF Fe/FeS -WMF Fe/FeS +WMF C/C.6.4 Fe/FeO -WMF Fe/FeO +WMF Fe/FeS -WMF Fe/FeS +WMF C/C.6.4 Fe/FeO -WMF Fe/FeO +WMF Fe/FeS -WMF Fe/FeS +WMF DO (mg/l) Fe(II) aq (mg/l) Eh(SHE) (mv) 3 8 D 8 E 6 6 DO (mg/l) 4 Fe/FeO -WMF Fe/FeO +WMF Fe/FeS -WMF Fe/FeS +WMF DO (mg/l) 4 Fe/FeO -WMF Fe/FeO +WMF Fe/FeS -WMF Fe/FeS +WMF Fe(II) aq (mg/l) Eh(SHE) (mv) 3 16 F 14 Fe(II) aq (mg/l) Fe/FeO -WMF Fe/FeO +WMF Fe/FeS -WMF Fe/FeS +WMF Eh(SHE) (mv) 3 Figure S6. Matrix of time series correlations for each combination of synchronously measured experimental parameters (C/C for Orange I, DO, Fe(II), and Eh). Treatment effects include WMF (color) and Fe/FeO and Fe/FeS (symbols). Data are from the same series of experiments in Figure S5, all of which were done in stirred, open batch reactors with ph = 7, Orange I C = 1 mg/l, Fe/FeO or Fe/FeS = 2 g/l, RPM = 4, T = 25 C. 1/1/16 S9

10 Figure S7. The major degradation pathway of Orange I by Fe/FeO and Fe/FeS. Only major species are shown; potentially relevant pka s (from chemicalize.org) are shown in blue. 1/1/16 S1

11 Figure S8. HPLC-MS analysis 1 of the disappearance of Orange I and the appearance of degradation product compared with standards for Orange I and sulfanilic acid. (A) Orange I (m/z = 327) and sulfanilic acid (m/z = 172), (B) Fe/FeO after reaction 1 min with WMF, (C) Fe/FeO after reaction 3 min with WMF, (D) Fe/FeO after reaction 6 min with WMF, (E) Fe/FeO after reaction 12 min with WMF. Conditions: ph = 7, Orange I C = 1 mg/l, Fe/FeO = 2 g/l, RPM = 4, T = 25 C. 1 Orange I and the reaction product were analyzed by HPLC-MS (Thermo Ultimate 3) equipped with a C18 column (15 mm 2.1 mm, 3 µm particles, Atlantis). The mobile phase was a mixture of water (.1% formic acid) and methanol at a flow rate of.2 ml/min. The methanol (v/v, %) gradient program was applied: -6 min (1%), 6-8 min (9%), and 8-1 min (1%). The injection volume was 5 µl. The negative ion mode was adopted in MS analysis, and the mass spectrometer was equipped with an ESI ion source. The temperature of drying gas was 35 C, and the flow rate of drying gas was 12 L/min. 1/1/16 S11

12 Figure S9. FTIR spectra of Fe/FeO and Fe/FeS after reactions with orange I with and without WMF. All data were obtained from stirred, open batch reactors with ph = 7, Orange I C = 1 mg/l, Fe/FeO or Fe/FeS = 2 g/l, RPM = 4, T = 25 C. 1/1/16 S12

13 1 A Orange I (mg/l) B DO (mg/l) Fe/FeS, WMF Fe/FeS, WMF Fe/FeS, + + WMF Fe/FeS, + + WMF C 3 Eh (mv vs SHE) Time (min) Figure S1. Time-series plots of (A) dye concentration, (B) dissolved oxygen concentration and (C) redox potential for re-spike batch experiments conducted with Fe/FeS and in the presence (or absence) of WMF during a given cycle as indicated in the legend by + (or ). Fe/FeO respike data presented in Figure 3. 1/1/16 S13

14 8 A 8 B [O 2,aq ] (mg/l) 6 4 [O 2,aq ] (mg/l) C = 5 mg/l C = 1 mg/l C = 2 mg/l Respike (to 1 mg/l) Time (min) Time (min) 8 C 8 D [O 2,aq ] (mg/l) 6 4 [O 2,aq ] (mg/l) Time (min) Time (min) Figure S11. Dissolved oxygen sag curves (A) Fe/FeO WMF, (B) Fe/FeS WMF, (C) Fe/FeO +WMF, and (D) Fe/FeS +WMF for varying levels of Orange I exposure (indicated in the legend). The respike experiments (blue asterisks) involved adjustment of the Orange I concentration back to the initial concentration of 1 mg/l on 3 min intervals, so these experiments resulted in the largest Orange I exposure levels. Passivation of the iron is indicated by the rebound of dissolved oxygen toward saturation. The dissolved oxygen rebound appears to be independent of Orange I exposure level thereby supporting our modeling hypothesis that passivation is driven by reaction of the iron surface with dissolved oxygen rather than with Orange I. 1/1/16 S14

15 Xu/Tratnyek (216) Figure S12. Fitting results from global analysis of all dissolved oxygen vs. time data. Top panel shows residuals vs. time. Bottom panel shows both the data (squares) and the model predictions (lines). 1/1/16 S15

16 Table S1. Summary of data for kinetic data for Fe/FeS and Fe/FeO with (+) and without ( ) WMF. Cmpd. Orange I Cmpd. Orange I k obs (Fe/FeS WMF) (min -1 ) k obs (Fe/FeO WMF) (min -1 ) R= k obs (Fe/FeS WMF)/ k obs (Fe/FeO WMF) Treatment Common Conditions Ref Fe/FeO or Fe/FeS = 1 g/l Open batch reactors, [C ] = 1 mg/l, Fe/FeO or Fe/FeS = 2 g/l RPM = 4, ph = 7. Treatment variable = Fe/FeO or Fe/FeS = 3 g/l [Fe/FeO or Fe/FeS] C = 5 mg/l Open batch reactors, [Fe/FeO or Fe/FeS] = C = 1 mg/l g/l, RPM = 4, ph = 7. Treatment C = 2 mg/l variable = [C ] mm Na 2 SO 4 Open batch reactors, [C ] = 1 mg/l, mm Na 2 SO 4 [Fe/FeO or Fe/FeS] = 2g/L, RPM = 4, ph = 7. Treatment variable = [Na 2 SO 4 ] mm IPA Open batch reactors, [C ] = 1 mg/l, mm IPA [Fe/FeO or Fe/FeS] = 2g/L, RPM = 4, ph = 7. Treatment variable = [IPA] [Fe(II)] = 4 mg/l Open batch reactors, [C ] = 1 mg/l, [Fe/FeO or Fe/FeS] = 2g/L, RPM = 4, ph [Fe(II)] = 8 mg/l = 7. Treatment variable = [Fe(II)]. k obs (Fe/FeS +WMF) (min -1 ) k obs (Fe/FeO WMF) (min -1 ) R = k obs (Fe/FeS +WMF)/ k obs (Fe/FeO WMF) Fe/FeO or Fe/FeS = 1 g/l Fe/FeO or Fe/FeS = 2 g/l Fe/FeO or Fe/FeS = 3 g/l C = 5 mg/l C = 1 mg/l C = 2 mg/l This work Treatment Common Conditions Ref. Open batch reactors, [C ] = 1 mg/l, RPM = 4, ph = 7. Treatment variable = [Fe/FeO or Fe/FeS ]. Open batch reactors, [Fe/FeO or Fe/FeS ] = 2 g/l, RPM = 4, ph = 7. Treatment variable = [C ]. This work 1/1/16 S16

17 Cmpd. Orange I Cmpd. Cmpd. Orange II k obs (Fe/FeO +WMF) (min -1 ) k obs (Fe/FeO WMF) (min -1 ) R= k obs (Fe/FeO +WMF)/ k obs (Fe/FeO WMF) Fe/FeO = 1 g/l Fe/FeO = 2 g/l Fe/FeO = 3 g/l C = 5 mg/l C = 1 mg/l C = 2 mg/l R= k obs (Fe/FeS k obs (Fe/FeS k obs (Fe/FeS +WMF)/ +WMF) WMF) k obs (Fe/FeS (min -1 ) (min -1 ) WMF) Fe/FeS = 1 g/l Fe/FeS = 2 g/l Fe/FeS = 3 g/l C = 5 mg/l C = 1 mg/l C = 2 mg/l k obs (Fe/FeO +WMF) (min -1 ) k obs (Fe/FeO WMF) (min -1 ) R = k obs (Fe/FeO +WMF)/ k obs (Fe/FeO WMF) ph = ph = ph = ph = 5.5 Treatment Common Conditions Ref. Open batch reactors, [C ] = 1 mg/l, RPM = 4, ph = 7. Treatment variable = [Fe/FeO]. Open batch reactors, [Fe/FeO] = 2 g/l, RPM = 4, ph = 7. Treatment variable = [C ]. This work Treatment Common Conditions Ref. Open batch reactors, [C ] = 1 mg/l, RPM = 4, ph = 7. Treatment variable = [Fe/FeS]. Open batch reactors, [Fe/FeS] = 2 g/l, RPM = 4, ph = 7. Treatment variable = [C ]. This work Treatment Common Conditions Ref. Open batch reactors, [C ] = 1 mg/l, [Fe/FeO] = 2 g/l, RPM = 45. Treatment variable = [ph] Fe/FeO =.5 g/l Open batch reactors, [C ] = 1 mg/l, [ph] Fe/FeO = 1 g/l = 3.3, RPM = 45. Treatment variable = 1/1/16 S17

18 Fe/FeO = 2 g/l [Fe/FeO] Fe/FeO = 5 g/l C = 25 mg/l Open batch reactors, [Fe/FeO] = 5 g/l, [ph] C = 5 mg/l = 3.3, RPM = 45. Treatment variable C = 15 mg/l =[C ]. 1/1/16 S18

19 Table S2. Information of Orange I and sulfanilic acid obtained by HPLC-MS. Cont. Condition Retention Time (min) Peak Area Concentration (mg/l) Note Orange I Sulfanilic acid Standard Sample min min min min Standard Sample min min min min Due to the instability of 1-amino-4- naphthol, it could not be identified by HPLC-MS in this study. Data are from the same series of experiments in Figure S8. 1/1/16 S19

20 Table S3. Summary of k obs (in min 1 ) of Fe/FeS and k obs of Fe/FeO in the respike experiment with (+) and without ( ) WMF. Category Label 1 st Cycle (k obs ± 1SD) 2 nd Cycle (k obs ± 1SD) 3 rd Cycle (k obs ± 1SD) 4 th Cycle (k obs ± 1SD) Common Conditions Ref. Fe/FeO Fe/FeS WMF WMF + + WMF + + WMF WMF WMF + + WMF + + WMF.46 ± ± ± ± ± ± ± ±.7.24 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±.5 Open batch reactors, [Fe/FeO] = 2 g/l, [C ] = 1 mg/l, RPM = 4, ph = 7. Treatment variable = respike. Open batch reactors, [Fe/FeS] = 2 g/l, [C ] = 1 mg/l, RPM = 4, ph = 7. Treatment variable = respike. This work 1/1/16 S2

21 Table S4. Model parameterization results from global analysis of DO data. k O2,depl and k O2,ra treated as global parameters. Data Set k O2,depl (min -1 mg -1 L) k O2,ra (min -1 ) [O 2,aq ] Sat (mg L -1 ) [S a ] t= (mg L -1 ) Fe/FeO 1 g/l; +WMF; Orange I, 1 mg/l.76 ± ± ± ±6.14 Fe/FeO 2 g/l; +WMF; Orange I, 1 mg/l 8.86 ± ±11.73 Fe/FeO 3g/L; +WMF; Orange I, 1 mg/l 8.67 ± ±14.5 Fe/FeO 1 g/l; WMF; Orange I, 1 mg/l 8.54 ± ±.98 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l 8.38 ± ±1.8 Fe/FeO 3g/L; WMF; Orange I, 1 mg/l 8.2 ± ± 1.7 Fe/FeO 2 g/l; Respike WMF; Orange I, 1 mg/l 8.33 ± ± Fe/FeO 2 g/l; Respike WMF; Orange I, 1 mg/l 8.21 ± ±.89 Fe/FeO 2 g/l; +WMF; Orange I, 5 mg/l 8.49 ± ± 9.66 Fe/FeO 2 g/l; +WMF; Orange I, 2 mg/l 8.96 ± ±9.87 Fe/FeO 2 g/l; WMF; Orange I, 5 mg/l 8.35 ± ± 1.9 Fe/FeO 2 g/l; WMF; Orange I, 2 mg/l 8.18 ± ±1.9 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l; Na 2 SO 4, 1 mm 8.83 ± ±2.72 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l; Na 2 SO 4, 2 mm 8.93 ± ± 6.61 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l; IPA, 5 mm 8.69 ± ± 1.5 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l; IPA, 1 mm' 8.37 ± ±1.8 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l; Fe 2+, 4 mg/l 8.2 ± ± 1.16 Fe/FeO 2 g/l; WMF; Orange I, 1 mg/l; Fe 2+, 8 mg/l 8.42 ± ± 1.43 Fe/FeO 2 g/l; Respike + + WMF; Orange I, 1 mg/l 8.39± ± 16.2 Fe/FeO 2 g/l; Respike + + WMF; Orange I, 1 mg/l 8.9 ± ± Fe/FeO 2 g/l; Respike + +WMF; Orange I, 1 mg/l 7.45 ± ±18.99 Fe/FeO 2 g/l; Respike + +WMF; Orange I, 1 mg/l 8.3 ± ±2.3 Fe/FeS 1 g/l; +WMF; Orange I, 1 mg/l 8.1 ± ± /1/16 S21

22 Fe/FeS 2 g/l; +WMF; Orange I, 1 mg/l 8.96 ± ± 9.73 Fe/FeS 3g/L; +WMF; Orange I, 1 mg/l 8.63 ± ±14.26 Fe/FeS 1 g/l; WMF; Orange I, 1 mg/l 8.45 ± ± 2.85 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l 8.27 ± ± 5.89 Fe/FeS 3g/L; WMF; Orange I, 1 mg/l 8.53 ± ± Fe/FeS 2 g/l; Respike WMF; Orange I, 1 mg/l 8.21 ± ± 1.1 Fe/FeS 2 g/l; Respike WMF; Orange I, 1 mg/l 8.17 ± ± 4.82 Fe/FeS 2 g/l; +WMF; Orange I, 5 mg/l 8.51 ± ± 8.8 Fe/FeS 2 g/l; +WMF; Orange I, 2 mg/l 8.95 ± ± 9.3 Fe/FeS 2 g/l; WMF; Orange I, 5 mg/l 8.78 ± ± Fe/FeS 2 g/l; WMF; Orange I, 2 mg/l 8.8 ± ± 7.88 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l; Na 2 SO 4, 1 mm 8.52 ± ± 9.18 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l; Na 2 SO 4, 2 mm 8.37 ± ± 8.14 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l; IPA, 5mM 8.89 ± ± 6.5 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l; ; IPA, 1 mm 8.71 ± ± 6.21 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l; Fe 2+, 4 mg/l 8.95 ± ±1.86 Fe/FeS 2 g/l; WMF; Orange I, 1 mg/l; Fe 2+, 8 mg/l 8.72 ± ± 9.37 Fe/FeS 2 g/l; Respike + + WMF; Orange I, 1 mg/l 8.72 ± ± Fe/FeS 2 g/l; Respike + +WMF; Orange I, 1 mg/l 8.89 ± ± /1/16 S22

23 References in Supporting Information 1. Li, J.; Qin, H.; Guan, X. Premagnetization for enhancing the reactivity of multiple zerovalent iron samples toward various contaminants. Environ. Sci. Technol. 215, 49 (24), Fan, D.; Anitori, R. P.; Tebo, B. M.; Tratnyek, P. G.; Lezama Pacheco, J. S.; Kukkadapu, R. K.; Engelhard, M. H.; Bowden, M. E.; Kovarik, L.; Arey, B. W. Reductive sequestration of pertechnetate ( 99 TcO 4 ) by nano zerovalent iron (nzvi) transformed by abiotic sulfide. Environ. Sci. Technol. 213, 47 (1), Rajajayavel, S. R. C.; Ghoshal, S. Enhanced reductive dechlorination of trichloroethylene by sulfidated nanoscale zerovalent iron. Water Res. 215, 78, Xiao, Z.; Zhou, Q.; Qin, H.; Qiao, J.; Guan, X. The enhancing effect of weak magnetic field on degradation of Orange II by zero-valent iron. Desalin. Water Treat. 216, 57 (4), /1/16 S23