scholarly journals Ochrobactrum anthropi used to control ammonium for nitrate removal by starch-stabilized nanoscale zero valent iron

2017 ◽  
Vol 76 (7) ◽  
pp. 1827-1832 ◽  
Author(s):  
Jun Zhou ◽  
Qianyu Sun ◽  
Dan Chen ◽  
Hongyu Wang ◽  
Kai Yang
Keyword(s):  
Nitrate Reduction ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Reduction Rate ◽  
Reduction Process ◽  
Zero Valent Iron ◽  
Ochrobactrum Anthropi ◽  
Iron Corrosion ◽  
Combined System ◽  
Nanoscale Zero Valent Iron

In this study, the hydrogenotrophic denitrifying bacterium Ochrobactrum anthropi was added in to the process of nitrate removal by starch-stabilized nanoscale zero valent iron (nZVI) to minimize undesirable ammonium. The ammonium control performance and cooperative mechanism of this combined process were investigated, and batch experiments were conducted to discuss the effects of starch-stabilized nZVI dose, biomass, and pH on nitrate reduction and ammonium control of this system. The combined system achieved satisfactory performance because the anaerobic iron corrosion process generates H2, which is used as an electron donor for the autohydrogenotrophic bacterium Ochrobactrum anthropi to achieve the autohydrogenotrophic denitrification process converting nitrate to N2. When starch-stabilized nZVI dose was increased from 0.5 to 2.0 g/L, nitrate reduction rate gradually increased, and ammonium yield also increased from 9.40 to 60.51 mg/L. Nitrate removal rate gradually decreased and ammonium yield decreased from 14.93 to 2.61 mg/L with initial OD600 increasing from 0.015 to 0.080. The abiotic Fe0 reduction process played a key role in nitrate removal in an acidic environment and generated large amounts of ammonium. Meanwhile, the nitrate removal rate decreased and ammonium yield also reduced in an alkaline environment.

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.

scholarly journals Removal of nitrate from water by acid-washed zero-valent iron/ferrous ion/hydrogen peroxide: influencing factors and reaction mechanism

2017 ◽  
Vol 77 (2) ◽  
pp. 525-533 ◽  
Author(s):  
Yongye Li ◽  
Fenglian Fu ◽  
Zecong Ding
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Mechanism ◽  
Photoelectron Spectroscopy ◽  
Nitrate Reduction ◽  
Nitrate Removal ◽  
Zero Valent Iron ◽  
Ferrous Ion ◽  
Combined System ◽  
X Ray ◽  
Before And After

Abstract In this paper, a system consisting of acid-washed zero-valent iron (ZVI), ferrous ion (Fe2+), and hydrogen peroxide (H2O2) was employed for the removal of nitrate (NO3−) from water, and the reaction mechanism for this is discussed. The effects of acid-washed ZVI, Fe2+, H2O2, and initial NO3− concentration on nitrate removal were investigated. Acid-washed ZVI before and after reaction with nitrate were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Results reveal that the combined system can enhance the corrosion of ZVI and facilitate aqueous nitrate reduction. The products of nitrate reduction are mainly ammonium, with some N2. The ZVI particles after reaction may have a core of ZVI with an oxidation layer mainly consisting of Fe3O4.

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.

scholarly journals Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1417
Author(s):  
Min Zhuang ◽  
Wen Shi ◽  
Hui Wang ◽  
Liqiang Cui ◽  
Guixiang Quan ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Surface Passivation ◽  
Bimetallic Nanoparticles ◽  
Zero Valent Iron ◽  
Molar Ratio ◽  
Particle Sizes ◽  
Iron Corrosion ◽  
Graphitized Carbon ◽  
Nanoscale Zero Valent Iron ◽  
Iron Nickel

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

INTEGRATING NANOSCALE ZERO-VALENT IRON AND TITANIUM DIOXIDE FOR NUTRIENT REMOVAL IN STORMWATER SYSTEMS

NANO ◽  
2008 ◽  
Vol 03 (04) ◽  
pp. 297-300 ◽  
Author(s):  
NI-BIN CHANG ◽  
MARTY WANIELISTA ◽  
FAHIM HOSSAIN ◽  
LEI ZHAI ◽  
KUEN-SONG LIN
Keyword(s):  
Titanium Dioxide ◽  
Water Reuse ◽  
Algal Blooms ◽  
Chemical Reduction ◽  
Nitrate Removal ◽  
Packed Bed ◽  
The United States ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron ◽  
Freshwater Bodies

Nutrients, such as nitrate, nitrite, and phosphorus, are common contaminants in many aquatic systems in the United States. Ammonia and nitrate are both regulated by the drinking water standards in the US primarily because excess levels of nitrate might cause methemoglobinemia. Phosphorus might become sources of the eutrophication problems associated with toxic algae in the freshwater bodies. Toxic algal blooms can cause severe acute and chronic public health problems. Chemical reduction of nitrate by using zero-valent iron started as early as 1964, and considerable research reports relating to this technology to nanomaterial were extensively reported in 1990s making the use of nanoscale zero-valent iron (NZVI) particles for nitrate removal become one of the most popular technologies in this field. The purpose of the present study was to examine the potential of integrating green sorption media, such as sawdust, limestone, tire crumb, and sand/silt, with two types of nanoparticles, including NZVI and Titanium Dioxide ( TiO 2), for nitrate removal in an engineering process. The study consists of running packed bed column tests followed by the addition of NZVI and TiO 2 to improve nitrate and phosphorus removal efficiency. Preliminary results in this paper show that the potential and advanced study may support the creation of design criteria of stormwater and groundwater treatment systems for water reuse in the future.

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

A Facile Strategy to Fabricate Nanoscale Zero-Valent Iron Decorated Graphene Oxide Composite for Dechloridation of Trichloroacetic Acid in Water

2018 ◽  
Vol 18 (12) ◽  
pp. 8252-8257 ◽  
Author(s):  
Huixuan Zhang ◽  
Xinyi Zhang ◽  
Ruonan Guo ◽  
Qingfeng Cheng ◽  
Xiuwen Cheng
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Sewage Treatment ◽  
Reduction Process ◽  
Zero Valent Iron ◽  
Chlorinated Organic Compounds ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Adsorption Desorption

In this study, nanoscale zero-valent iron decorated graphene oxide (NZVI/GO) composite was fabricated through a reduction process in the presence of sodium borohydride (NaBH4) solution. Subsequently, physicochemical properties of the NZVI/GO composites were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR) and Raman spectra. Results indicated that Fe species existed in the form of Fe0, which uniformly dispersed on the surface of GO. Furthermore, the performance of NZVI/GO was evaluated by the degradation of tichloroacetic acid (TCAA). TCAA can be rapidly degraded by NZVI/GO. This paper provides a promising strategy to synthesize versatile catalyst which would be potentially applied in sewage treatment to degrade chlorinated organic compounds.

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
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