Degradation of bromamine acid by nanoscale zero-valent iron (nZVI) supported on sepiolite

2012 ◽  
Vol 66 (12) ◽  
pp. 2539-2545 ◽  
Author(s):  
Xuening Fei ◽  
Lingyun Cao ◽  
Lifeng Zhou ◽  
Yingchun Gu ◽  
Xiaoyang Wang
Keyword(s):  
Ph Value ◽  
Energy Dispersive Spectrometer ◽  
Zero Valent Iron ◽  
Mass Ratio ◽  
Initial Concentration ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph ◽  
Set Up

Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.

scholarly journals Surface coating with Ca(OH)2 for improvement of the transport of nanoscale zero-valent iron (nZVI) in porous media

2013 ◽  
Vol 68 (10) ◽  
pp. 2287-2293 ◽  
Author(s):  
Cai-jie Wei ◽  
Xiao-yan Li
Keyword(s):  
Porous Media ◽  
Surface Coating ◽  
Coating Layer ◽  
Zero Valent Iron ◽  
Mass Ratio ◽  
Batch Experiments ◽  
Effective Protection ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Protection Layer

A novel thermal deposition method was developed to coat Ca(OH)2 on the surface of nanoscale zero-valent iron (nZVI). The nZVI particles with the Ca(OH)2 coating layer, nZVI/Ca(OH)2, had a clear core-shell structure based on the transmission electron microscopy observations, and the Ca(OH)2 shell was identified as an amorphous phase. The Ca(OH)2 coating shell would not only function as an effective protection layer for nZVI but also improve the mobility of nZVI in porous media for its use in environmental decontamination. A 10% Ca/Fe mass ratio was found to result in a proper thickness of the Ca(OH)2 shell on the nZVI surface. Based on the filtration tests in sand columns, the Ca(OH)2-based surface coating could greatly improve the mobility and transport of nZVI particles in porous media. In addition, batch experiments were conducted to evaluate the reactivity of Ca(OH)2-coated nZVI particles for the reduction of Cr(VI) and its removal from water.

Removal of a Di-Azo Dye Acid Red 73 Synthetic Wastewater by Advanced Fenton Process Based on Nanoscale Zero-Valent Iron

2012 ◽  
Vol 518-523 ◽  
pp. 2718-2721
Author(s):  
Feng Lian Fu ◽  
Zhi Hong Chen ◽  
Qi Wang
Keyword(s):  
Azo Dye ◽  
Ph Value ◽  
Zero Valent Iron ◽  
Color Removal ◽  
Synthetic Wastewater ◽  
H2o2 Concentration ◽  
Fenton Process ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph ◽  
Acid Red 73

In this study, the removal of a di-azo dye, C.I. Acid Red 73 synthetic wastewater was investigated using advanced Fenton process based on nanoscale zero-valent iron (NZVI) that was synthesized by the aqueous phase borohydride reduction method in the laboratory. NZVI has been characterized by SEM. The influences of NZVI dosage, H2O2 concentration and initial pH value in the process of dye removal by advanced Fenton process were studied in a batch setting. The color removal efficiency was found to be decreased with increase of initial pH, and increased with increase of NZVI and H2O2 concentration. By using proposed process with NZVI dose of 0.02 g/L and H2O2 concentration of 1.0 mM, at 30 min the Acid Red 73 color removal was more than 90%.

Application of coupled zero-valent iron/biochar system for degradation of chlorobenzene-contaminated groundwater

2016 ◽  
Vol 75 (3) ◽  
pp. 571-580 ◽  
Author(s):  
Xu Zhang ◽  
Yanqing Wu
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Ph Value ◽  
Cost Effective ◽  
Zero Valent Iron ◽  
Contaminated Groundwater ◽  
Mass Ratio ◽  
Chlorinated Organic Compounds ◽  
Initial Ph ◽  
Chlorinated Organic

A novel iron-carbon micro-electrolysis system, bamboo-derived biochar coupled with zero-valent iron (ZVI), was investigated for chlorobenzene (CB)-contaminated groundwater removal. Influences of initial pH value, mass ratio of the ZVI/Biochar, initial CB concentration and ionic strength of the ZVI/Biochar micro-electrolysis were studied. The results indicated that the increase of initial pH led to the decrease of the CB removal efficiency. While the optimum mass ratio of ZVI to biochar was 2:1, the improved initial concentration and reaction time were 33.68 mg/L and 4 h, respectively. When pH of 2, mass ratio of 2:1 and reaction time of 4 h were applied, the CB removal efficiency was 99.92%. Enhanced degradation of CB was observed with increased Cl− concentration. When the Cl− concentration of 1,000 mg/L and reaction time of 1 h were applied, the CB removal efficiency arrived at 98.2%. Additionally, considering that biochar is cost-effective and readily produced, the coupled ZVI/Biochar micro-electrolysis could represent an effective approach for the treatment of groundwater containing chlorinated organic compounds in the future.

scholarly journals Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment

2021 ◽  
Vol 18 (11) ◽  
pp. 5921
Author(s):  
Haiyan Song ◽  
Wei Liu ◽  
Fansheng Meng ◽  
Qi Yang ◽  
Niandong Guo
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Inhibitory Effect ◽  
Ultrasonic Cavitation ◽  
Zero Valent Iron ◽  
Ultrasonic Pretreatment ◽  
Nanoscale Zero Valent Iron ◽  
Passivation Layers ◽  
Initial Ph ◽  
Two Phases

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO42−, NO3−, and Cl− had a strong inhibitory effect on this process, while the presence of SO42− promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe2+ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe0 core was exposed, which improved the reactivity of the composites.

High Cr(VI) Adsorption Performance of Coal-Based Activated Carbon in Aqueous Solution

2013 ◽  
Vol 798-799 ◽  
pp. 1123-1127
Author(s):  
Hua Lei Zhou ◽  
Qiong Qiong Zhu ◽  
Dong Hua Huang
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Pore Structure ◽  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Koh Activation ◽  
Transmission Electron ◽  
Mesoporous Adsorbent ◽  
Initial Ph

The activated carbon with high surface area was prepared by KOH activation from anthracite and used as adsorbent for removal of Cr (VI) from aqueous solution. The pore structure and surface properties were characterized by N2 adsorption at 77K, transmission electron microscope (TEM) and Fourier transform infrared spectroscopy ( FTIR). Effect of pH and isotherms at different temperature were investigated. Results show that the prepared carbon is a microporous-and mesoporous-adsorbent with developed pore structure and abundant surface oxygen-containing groups. PH value of the solution plays key function on the adsorption. The chemical adsorption dominates the adsorption process. The activated carbon exhibits much higher Cr adsorption capacity than the commercial activated carbon at initial pH of ~3. The equilibrium adsorption data are fitted by both Freundlich model and Langmuir model well.

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.

Enhanced Removal of Mercury and Lead by a Novel and Efficient Surface-functionalized Imogolite with Nanoscale Zero-valent Iron Material

2021 ◽  
Author(s):  
Estefanía Martinis ◽  
Juliano Denardin ◽  
Raul Calderón Raul Calderón ◽  
Cristóbal Flores ◽  
Karen Manquián-Cerda ◽  
...  
Keyword(s):  
Multicomponent System ◽  
Kinetic Studies ◽  
Zero Valent Iron ◽  
Hybrid Nanomaterial ◽  
Adsorption Sites ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Equilibrium Data ◽  
Softness Parameter ◽  
Chemical Procedure

Abstract A novel hybrid nanomaterial, nanoscale zero-valent iron (nZVI)-grafted imogolite nanotubes (Imo), was synthesized via a fast and straightforward chemical procedure. The as-obtained nanomaterial (Imo-nZVI) was characterized using transmission electron microscopy (TEM), electrophoretic mobility (EM) and vibrating sample magnetometry (VSM). The prepared Imo-nZVI was superparamagnetic at room temperature and could be easily separated by an external magnetic field. Sorption batch experiments were performed in single- and multicomponent system and showed that Hg2+ and Pb2+ could be quantitatively adsorbed at pH 4.0 with maximum adsorption capacities of 62.3 and 73.8 mg·g− 1, respectively. It was observed that the functional groups in Imo-nZVI interact preferentially with analytes according to Misono Softness parameter. The higher performance of Imo-nZVI compared with Imo and nZVI is related to the increased adsorption sites in the functionalized nanomaterial. The sorption equilibrium data obeyed the Langmuir model, while kinetic studies demonstrated that the sorption processes of Hg2+ and Pb2+ followed the pseudo-second-order model. This study suggests that the Imo-nZVI composite can be used as a promising sorbent and provides a simple and fast separation method for the removal of Hg and Pb ions from contaminated water.

SYNTHESIS AND OPTICAL PROPERTIES OF WATER SOLUBLE ZnSe NANOCRYSTALS

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3881-3884 ◽  
Author(s):  
N. Murase ◽  
M. Y. Gao ◽  
N. Gaponik ◽  
T. Yazawa ◽  
J. Feldmann
Keyword(s):  
Ph Value ◽  
Water Soluble ◽  
Final Solution ◽  
Blue Fluorescence ◽  
Wet Chemistry ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Mean Size ◽  
Surface Capping ◽  
Znse Nanocrystals

ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under ZV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after ~ 40 hrs. The final mean size of the ZnSe nanocrystals measured by transmission electron microscopy is aboyt 2 nm in diameter. The quantum efficiency of the fluorescence form the final solution is estimated to be ~1%, although the preparation conditions have not yet been completely optimized. These properties are discussed in comparison with those of similarly prepared CdTe and differently prepared ZnSe nanocrystals.

scholarly journals Fenton-Like Oxidation of Antibiotic Ornidazole Using Biochar-Supported Nanoscale Zero-Valent Iron as Heterogeneous Hydrogen Peroxide Activator

2020 ◽  
Vol 17 (4) ◽  
pp. 1324 ◽  
Author(s):  
Yanchang Zhang ◽  
Lin Zhao ◽  
Yongkui Yang ◽  
Peizhe Sun
Keyword(s):  
Oxidation Process ◽  
Zero Valent Iron ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Promising Alternative ◽  
Nanoscale Zero Valent Iron ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
H2o2 System

Biochar (BC)-supported nanoscale zero-valent iron (nZVI-BC) was investigated as a heterogeneous Fenton-like activator to degrade the antibiotic ornidazole (ONZ). The characterization of nZVI-BC indicated that BC could enhance the adsorption of ONZ and reduce the aggregation of nZVI. Thus, nZVI-BC had a higher removal efficiency (80.1%) than nZVI and BC. The effects of parameters such as the nZVI/BC mass ratio, pH, H2O2 concentration, nZVI-BC dose, and temperature were systematically investigated, and the removal of ONZ followed a pseudo-second-order kinetic model. Finally, possible pathways of ONZ in the oxidation process were proposed. The removal mechanism included the adsorption of ONZ onto the surface of nZVI-BC, the generation of •OH by the reaction of nZVI with H2O2, and the oxidation of ONZ. Recycling experiments indicated that the nZVI-BC/H2O2 system is a promising alternative for the treatment of wastewater containing ONZ.

scholarly journals The nanostructure of barium dititanate prepared by hydrothermal method

2019 ◽  
Vol 09 (02) ◽  
pp. 1950011
Author(s):  
Sarah L. Rasheed ◽  
Emad K. Al-Shakarchi
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Hydrothermal Method ◽  
Ph Value ◽  
Hydrothermal Process ◽  
Dielectric Ceramic ◽  
Lattice Constants ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Lcr Meter

The dielectric ceramic of barium dititanate compound BaTi2O5 had been prepared through the hydrothermal process by applying different parameters, such as pH-value, reaction time, temperature and pressure. The prepared powders were examined by X-ray diffraction (XRD). The predominant phase was a monoclinic phase with lattice constants ([Formula: see text], [Formula: see text], [Formula: see text] Å), ([Formula: see text], [Formula: see text]), and the unit cell volume (527 Å3). The surface morphology was demonstrated by Scanning Electron Microscopy (SEM). It exhibited the grains in spherical and elliptical shapes with high homogeneity. The shapes of nanostructure were analyzed by Transmission Electron Microscopy (TEM). The appearance of nanostructures like the nanoparticles and nano rods were found. The size of nanoparticles was in the range of 9–31[Formula: see text]nm, and size of nanorods was 32–37[Formula: see text]nm. The dielectric measurements were done by using LCR meter at different temperature and frequencies (10, 50 and 100[Formula: see text]kHz). It was clear that the Curie temperature had a high value up to (485∘C). The relative permittivity was partially changed for two prepared samples regarding high pressure and long reaction time, which were the main preparation conditions of hydrothermal method.

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