Nitrate reduction over nanoscale zero-valent iron prepared by hydrogen reduction of goethite

2012 ◽  
Vol 133 (1) ◽  
pp. 205-211 ◽  
Author(s):  
H.B. Liu ◽  
T.H. Chen ◽  
D.Y. Chang ◽  
D. Chen ◽  
Y. Liu ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Hydrogen Reduction ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron

Evaluation of nanoscale zero valent iron filled column for nitrate reduction

2018 ◽  
Vol 32 (3) ◽  
pp. 243-251 ◽  
Author(s):  
Youngpyoe Hong ◽  
Younggyo Seo ◽  
Hyowon Kim ◽  
Yuhoon Hwang
Keyword(s):  
Nitrate Reduction ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron

Promoting nitrate reduction kinetics by nanoscale zero valent iron in water via copper salt addition

2016 ◽  
Vol 287 ◽  
pp. 367-380 ◽  
Author(s):  
Ahmed M.E. Khalil ◽  
Osama Eljamal ◽  
Skander Jribi ◽  
Nobuhiro Matsunaga
Keyword(s):  
Nitrate Reduction ◽  
Zero Valent Iron ◽  
Copper Salt ◽  
Reduction Kinetics ◽  
Salt Addition ◽  
Nanoscale Zero Valent Iron

Fate of nitrogen species in nitrate reduction by nanoscale zero valent iron and characterization of the reaction kinetics

2010 ◽  
Vol 61 (3) ◽  
pp. 705-712 ◽  
Author(s):  
Y. H. Hwang ◽  
D. G. Kim ◽  
Y. T. Ahn ◽  
C. M. Moon ◽  
H. S. Shin
Keyword(s):  
Nitrate Reduction ◽  
Chemical Reduction ◽  
Reduction Rate ◽  
Zero Valent Iron ◽  
Ammonium Ion ◽  
Alkaline Condition ◽  
Order Kinetic ◽  
Nitrogen Species ◽  
Nanoscale Zero Valent Iron ◽  
Fate Of Nitrogen

This study investigates the fate of nitrogen species during nitrate reduction by nanoscale zero valent iron (NZVI) as well as the related kinetics. The NZVI used for the experiments was prepared by chemical reduction without a stabilizing agent. The pseudo first order kinetic constant of nitrate reduction at 30°C with an NZVI/nitrate ratio of 1.25:1, which were the reference conditions of this study, was 4.08 h−1 (R2 = 0.955). A nitrogen mass balance was established by quantitative analysis of aqueous-phase and gas-phase nitrogen species. The results confirm that the nitrate was converted to ammonium ion, that ammonia stripping subsequently occurred under a strong alkaline condition, and that the total amount of aqueous nitrogen was consequently reduced. The nitrate reduction rate also increased with a lower pH and a higher temperature when microscale ZVI was used. However, in contrast to the reaction by microscale ZVI, the nitrate reduction rate by NZVI was higher for an unbuffered condition, possibly due to the abundance of surface atoms and the smaller size.

Nitrate Reduction Using Nanoscale Zero Valent Iron Supported by Porous Suspended Ceramsite

2013 ◽  
Vol 726-731 ◽  
pp. 677-682
Author(s):  
Run Hua Liao ◽  
Yu Miao ◽  
Yan Hong ◽  
Yue Ming Li ◽  
Zong Yang Shen ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Reduction Rate ◽  
Zero Valent Iron ◽  
Ph Change ◽  
Nanoscale Zero Valent Iron

Porous suspended ceramsite (PSC) supported nanoscale zero valent iron (NZVI/PSC) were applied to the reductive removal of nitrate to investigate the effects. XRD, SEM and EDS analyses on NZVI/PSC revealed that PSC had loaded some nanoparticles, whose size was about 50 nm. Nitrate reduction rate of NZVI/PSC reached about 80% in 60 min, while the PSC unsupported nanozerovalent iron performed poorly with only 8% removal of the nitrate. Furthmore, during the reactions of NZVI/PSC and PSC with nitrate, for the NZVI/PSC, pH change was the greatest, while the reaction with PSC (this particles shows the lowest reactivity for nitrate reduction) resulted in the least pH change.

scholarly journals Improved Affinity of Nanoscale Zero Valent Iron toward Hydrophobic Organic Solvent using Poly(1-vinylpyrrolidone-co-vinyl acetate)

2020 ◽  
Vol 42 (9) ◽  
pp. 431-441
Author(s):  
Jeongmin Hong ◽  
Hayeon Yang ◽  
Taeyeon Cha ◽  
Younggyo Seo ◽  
Yuhoon Hwang
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Vinyl Acetate ◽  
Soil Remediation ◽  
Organic Contaminants ◽  
Nitrate Reduction ◽  
Groundwater Remediation ◽  
Reduction Rate ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron

Objectives : Levels of organic contaminants in excess of the standard minimum have been detected in many commercial and residential sites, and the severity of soil and groundwater pollution is increasing. In particular, non-aqueous phase liquids (NAPLs) are hydrophobic organic pollutants that do not mix with water and are difficult to remove with existing soil remediation technology. These pollutants slowly dissolve into the groundwater over long periods of time, thus contaminating the groundwater. With the increasing need to remove NAPLs for soil and groundwater remediation, widespread interest has focused on the use of nanoscale zero valent iron (nZVI). However, nZVI has the disadvantage of reduced subsurface mobility. Hence, in the present study, the nZVI surface is modified with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), which has both hydrophilic and hydrophobic groups, to improve the mobility and selectivity of nZVI for the removal of NAPL.Methods : The PVP/VA modified nZVI is synthesized through the reaction of FeSO4･7H2O and NaBH4 in the presence of PVP/VA. To confirm the dispersibility of the prepared material, a precipitation experiment is performed using a visible light spectrometer, and the mobility through a sand-filled column is evaluated. In addition, the variation in particle size and characteristics according to the presence of PVP/VA is examined via transmission electron microscopy. The nitrate reduction ability of nZVI with PVP/VA is also evaluated to reveal changes in reactivity depending upon the degree of dispersion. To confirm the selective mobility towards NAPL, trichloroethylene and dodecane are used to evaluate the mobility with and without PVP/VA. Finally, the ratio of nZVI passing through the sponge layer absorbing dodecane is evaluated to determine the selective mobility towards NAPL in the porous medium.Results and Discussion : Although the dispersibility of the PVP/VA-nZVI is not significantly changed, the particle size is significantly decreased. Both the mobility in porous media and the nitrate reduction rate are improved via PVP/VA modification. The affinity for hydrophobic contaminants and the selective migration of PVP/VA-nZVI towards the NAPL layer are also improved. The high affinity for the NAPL was also shown by the column with NAPL layer.Conclusions : Surface-modification with PVP/VA, which has both hydrophilic and hydrophobic ends, enabled the synthesis of nZVI with a smaller and more uniform particle size, thus providing high mobility in porous media and high reactivity towards contaminants. The combined hydrophilicity and hydrophobicity of PVP/VA is shown to increase the affinity of nZVI towards NAPL and, thus, promote its migration to the NAPL layer. Thus, it is anticipated that the efficiency of soil remediation can be improved by promoting the movement of nZVI towards the target NAPL layer.

Decreasing ammonium generation using hydrogenotrophic bacteria in the process of nitrate reduction by nanoscale zero-valent iron

2009 ◽  
Vol 407 (21) ◽  
pp. 5465-5470 ◽  
Author(s):  
Yi An ◽  
Tielong Li ◽  
Zhaohui Jin ◽  
Meiying Dong ◽  
Qianqian Li ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron
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