Feasibility of nanoscale zero-valent iron to enhance the removal efficiencies of heavy metals from polluted soils by organic acids

2018 ◽  
Vol 162 ◽  
pp. 464-473 ◽  
Author(s):  
Yaru Cao ◽  
Shirong Zhang ◽  
Qinmei Zhong ◽  
Guiyin Wang ◽  
Xiaoxun Xu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Organic Acids ◽  
Zero Valent Iron ◽  
Polluted Soils ◽  
Nanoscale Zero Valent Iron ◽  
Removal Efficiencies

scholarly journals Removal efficiency of hexavalent chromium from wastewater using starch-stabilized nanoscale zero-valent iron

2019 ◽  
Vol 80 (6) ◽  
pp. 1076-1084 ◽  
Author(s):  
Hualin Chen ◽  
Huajun Xie ◽  
Jiangmin Zhou ◽  
Yueliang Tao ◽  
Yongpu Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Reactivity ◽  
Zero Valent Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phase Reduction ◽  
Nanoscale Zero Valent Iron ◽  
Removal Efficiencies ◽  
Ph Range ◽  
Uniform Particle Size

Abstract In this study, starch-stabilized nanoscale zero-valent iron (S-nZVI) was produced using the liquid-phase reduction method. It was used to remove chromium from wastewater, and compared to a commercial nanoscale zero-valent iron (C-nZVI). Both nZVIs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The characterization results showed that S-nZVI had smaller particles and a more uniform particle size distribution than C-nZVI. Both nZVIs showed a core-shell structure with the Fe0 core prominently surrounded by less iron oxides of Fe2+ and Fe3+. The optimal application methods to remove Cr(VI) from wastewater were also explored. The results showed that both the removal efficiencies of total Cr and Cr(VI) increased with increases in the addition of nZVIs, while the removal efficiencies of total Cr and Cr(VI) by S-nZVI were clearly higher than that of C-nZVI, especially in a low pH range (pH = 1.0–6.0). This research indicated that starch-stabilized nanoscale zero-valent iron is a valuable material to remove heavy metals from wastewater due to its stability and high reactivity.

scholarly journals A porous biochar supported nanoscale zero-valent iron highly efficient for the remediation of cadmium and lead contaminated soil

2021 ◽  
Author(s):  
Wei Qian ◽  
Zeng-Hui Diao
Keyword(s):  
Heavy Metals ◽  
Clayey Soil ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron ◽  
Cadmium And Lead ◽  
Concentration Levels ◽  
Pb Immobilization ◽  
Better Than ◽  
Cd Species ◽  
Simultaneous Immobilization

Abstract Risk associated with heavy metals in soil has been received widespread attention. In this study, a porous biochar supported nanoscale zero-valent iron (BC-nZVI) was applied to immobilize cadmium (Cd) and/or lead (Pb) in clayey soil. Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process, and about 80 % of heavy metals immobilization was obtained in BC-nZVI process. Addition of BC-nZVI could increase soil pH and organic matter (SOM). Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol (2,4-DCP), but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels. Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process, and both Cd and Pb availability significantly decreased. Stable Cd species inculding Cd(OH)2, CdCO3 and CdO were formed, whereas stable Pb species such as PbCO3, PbO and Pb(OH)2 were produced with BC-nZVI treatment. Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed. This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple metals in soil.

APPLICATION OF NANOSCALE ZERO-VALENT IRON FOR GROUNDWATER REMEDIATION: LABORATORY AND PILOT EXPERIMENTS

NANO ◽  
2008 ◽  
Vol 03 (04) ◽  
pp. 287-289 ◽  
Author(s):  
STEPANKA KLIMKOVA ◽  
MIROSLAV CERNIK ◽  
LENKA LACINOVA ◽  
JAROSLAV NOSEK
Keyword(s):  
Heavy Metals ◽  
Groundwater Remediation ◽  
Laboratory Experiments ◽  
Permeable Reactive Barriers ◽  
Zero Valent Iron ◽  
Chlorinated Ethenes ◽  
Soluble Form ◽  
Chemical Decontamination ◽  
Nanoscale Zero Valent Iron

It is known that the reductive effects of zero-valent iron ( Fe 0) and the sorptive capability of iron and its oxides can be used for both the dehalogenation of chlorinated hydrocarbons (CHC), especially of chlorinated ethenes (PCE → TCE → DCE → VC → ethene, ethane), and the removing of heavy metals from groundwater by turning them into a less-soluble form through changes of their oxidation state, or by adsorption. These consequences are being exploited in the construction of iron filling permeable reactive barriers for a longer time.1 The advantages of nanoscale zero-valent iron ( nanoFe 0) over the macroscopic one consist not only in the better reactivity implicit in their greater specific surface area but also in their mobility in rock environment.2,3 Numerous laboratory experiments, especially the batch-agitated experiments, with samples from seven various contaminated localities in Europe have been carried out with the aim to discover the measurement of the reductive effect of the nanoFe 0 on selected contaminants. It was found that the nanoFe 0 can be reliably usable as a reductive reactant for in-situ chemical decontamination of sites polluted by chlorinated ethenes (CEs), or hexa-valent chromium ( Cr VI ). The rate of reductive reaction and the optimal concentrations for the real remediation action were determined. On the basis of these laboratory experiments, the methods for pilot application of nanoFe 0 have been specified. Subsequently the pilot experiments were accomplished in surveyed localities.

scholarly journals Phytoextraction and fractionation of heavy metals in soil after multiple applications of natural chelants

2008 ◽  
Vol 65 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Évio Eduardo Chaves de Melo ◽  
Clístenes Williams Araújo do Nascimento ◽  
Adriana Maria de Aguiar Accioly ◽  
Ana Cristiane Queiroz Santos
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Organic Acids ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Velvet Bean ◽  
Polluted Soils ◽  
Metal Concentrations ◽  
Synthetic Agents ◽  
Assisted Phytoextraction

Chelate-assisted phytoextraction of heavy metals is a promising approach to clean up polluted soils. However, the most successful chelants tested so far are synthetic agents that barely degrade in soil, increasing the metal leaching risks. Natural organic acids have been proposed to enhance phytoextraction due to their higher biodegradability, but they can also be a drawback for efficient phytoextraction. This work was carried out to compare the effectiveness of multiple applications of citric and gallic acids on the availability in soil and accumulation of Cd, Pb, Cu, and Zn by velvet bean (Stizolobium aterrimum) plants. The organic acids were added as follows: 5 mmol kg-1 in the 28th cultivation day; two doses of 5 mmol kg-1 at the 28th and 31st day; and three applications at the same rate at the 28th, 31st, and 34th day of velvet bean cultivation. Soil samples were sequentially extracted and soil solution metal concentrations assessed. Neither citric acid nor gallic acid was efficient for metals phytoextraction. In general, low molecular weight organic acids (LMWOA) application increased the metal concentrations in the water soluble and exchangeable fractions. Zinc and Cu were retained mostly in the organic matter fraction. Zn was remobilized from the organic matter fraction through LMWOA application into the water soluble and exchangeable fractions. LMWOA mobilized Pb and Cu from iron oxides, but such an increase in solubility was not high enough to affect phytoextraction.

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