Nanoscale zero-valent iron@mesoporous hydrated silica core-shell particles with enhanced dispersibility, transportability and degradation of chlorinated aliphatic hydrocarbons

Chen, Shuai; Bedia, Jorge; Li, Hui; Ren, Lu Yao; Naluswata, Fauzia; Belver, Carolina

doi:10.1016/j.cej.2018.03.011

Cited by 59 publications

(14 citation statements)

References 49 publications

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“…TEM analysis revealed that the average size of bare and CMC-nZVI nanoparticles ranged between 30 and 70 and 20 and 50 nm, respectively ( Figure 3). These values are consistent with the results from several previous studies [15,31,32]. The average hydrodynamic size measured by dynamic light scattering (DLS) of nZVI nanoparticles differed significantly from the diameter of single nZVI particles measured by TEM analysis (Table 1).…”

Section: Properties Of the Synthesized Nzvi Particlessupporting

confidence: 91%

Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

et al. 2019

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Efficient application of nanoscale zero-valent iron (nZVI) particles in remediation processes relies heavily on the ability to modify the surfaces of nZVI particles to enhance their stability and mobility in subsurface layers. We investigated the effect of sodium carboxy-methyl-cellulose (CMC) polymer stabilizer, pH, particle concentration, and flow rate on the transport of nZVI particles in sand columns. Breakthrough curves (BTCs) of nZVI particles indicated that the transport of nZVI particles was increased by the presence of CMC and by increasing the flow rate. The relative concentration (RC) of the eluted CMC-nZVI nanoparticles was larger at pH 9 as compared to RC at pH 7. This is mainly attributed to the increased nZVI particle stability at higher pH due to the increase in the electrostatic repulsion forces and the formation of larger energy barriers. nZVI particle deposition was larger at 0.1 cm min −1 flow due to the increased residence time, which increases the aggregation and settlement of particles. The amount of CMC-nZVI particles eluted from the sand columns was increased by 52% at the maximum flow rate of 1.0 cm min −1 . Bare nZVI were mostly retained in the first millimeters of the soil column, and the amount eluted did not exceed 1.2% of the total amount added. Our results suggest that surface modification of nZVI particles was necessary to increase stability and enhance transport in sandy soil. Nevertheless, a proper flow rate, suitable for the intended remediation efforts, must be considered to minimize nZVI particle deposition and increase remediation efficiency.

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Section: Properties Of the Synthesized Nzvi Particlessupporting

confidence: 91%

Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

et al. 2019

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“…The rate constants for a pseudo second-order reaction were 0.0259 g/(mg·min) for 20 mg/L, 0.0048 g/(mg·min) for 100 mg/L, and 0.0025 g/(mg·min) for 200 mg/L, respectively. The result indicates that the degradation of MO occurs in the interface of BC-nZVI [20,22], hence the rate of degradation was closely linked to the initial concentration of MO and the active surface sites of BC-nZVI, as discussed in the previous section. It should be emphasized that the BC-nZVI materials in our study were prepared by the mechanical agitation method and most of nZVI particles are mainly distributed in the outer layer of BC.…”

Section: Kinetics Of Degradation Of Mosupporting

confidence: 52%

“…No characteristic diffraction peaks of Fe were observed because of its weak crystallization and the inclusion of DBS. The characteristic peaks have several small peaks at 2θ = 17.41°, 19.24°, and 3.84° on nZVI wave lines, which represent iron oxide [22], indicating a certain oxidation in the nanoparticles. In the characteristic peak of the BC-nZVI wave lines, there were obvious carbon peaks at 2θ = 26.60°, 43.45°, 54.79° [23] and the iron oxide peak disappears, indicating that the loading was beneficial to prevent the oxidation of the nZVI.…”

Section: Characterization Of Nzvi and Bc-nzvimentioning

confidence: 99%

“…The removal percentage of MO can be effectively improved with higher temperature, larger BC-nZVI dosage, and lower initial concentration of MO at the pH of 7 condition. 2 of 11 carrier, such as kaolinite [14], bentonite [15], resin [16], activated carbon [17], mesoporous carbon [18], mesoporous silica [19], titanium oxide [20], pumice [1,21], and grapheme [22], through the liquid phase reduction method. Nevertheless, there still has some problems associated with method, such as low production efficiency, high production cost, and large amounts of hydrogen the generation during the preparation process [23,24].…”

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Preparation of Biomass Activated Carbon Supported Nanoscale Zero-Valent Iron (Nzvi) and Its Application in Decolorization of Methyl Orange from Aqueous Solution

Zhang

Wang

2019

Water

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The nanoscale zero-valent iron (nZVI) has great potential to degrade organic polluted wastewater. In this study, the nZVI particles were obtained by the pulse electrodeposition and were loaded on the biomass activated carbon (BC) for synthesizing the composite material of BC-nZVI. The composite material was characterized by SEM-EDS and XRD and was also used for the decolorization of methyl orange (MO) test. The results showed that the 97.94% removal percentage demonstrated its promise in the remediation of dye wastewater for 60 min. The rate of MO matched well with the pseudo-second-order model, and the rate-limiting step may be a chemical sorption between the MO and BC-nZVI. The removal percentage of MO can be effectively improved with higher temperature, larger BC-nZVI dosage, and lower initial concentration of MO at the pH of 7 condition.

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“…In order to avoid nZVI agglomeration, much porous materials support was used to improve nZVI's dispersion, increase reactive sites, remove pollutants synergistically, and improve the mobility of nZVI [20][21][22][23] . Porous materials made up for the shortcomings of nZVI and greatly improved the ability of nZVI to remove pollutants.…”

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confidence: 99%

Study on influencing factors and mechanism of removal of Cr(VI) from soil suspended liquid by bentonite-supported nanoscale zero-valent iron

Liu

Gao

Cheng

et al. 2020

Sci Rep

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In order to clarify the mechanism and effect of bentonite-supported nanoscale zero-valent iron (nZVI@Bent) on Cr(VI) removal in soil suspended liquid, nZVI@Bent was prepared by liquid-phase reduction method in this research. A number of factors, including the mass ratio of Fe 2+ to bentonite during preparation of nZVI@Bent, nZVI@Bent dosage, soil suspended liquid pH value and reaction temperature were assessed to determine their impact on the reduction of Cr(VI) in soil suspended liquid. The nZVI@Bent was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to analyze the mechanism of removal of Cr(VI) from the soil. The results showed that the temperature of soil suspended liquid had a significant effect on the removal efficiency. Calculated by the Arrhenius formula, nZVI@Bent removes Cr(VI) from the soil suspended liquid as an endothermic reaction with a reaction activation energy of 47.02 kJ/mol, showed that the reaction occurred easily. The removal of mechanism Cr(VI) from the soil by nZVI@Bent included adsorption and reduction, moreover, the reduction process can be divided into direct reduction and indirect reduction. According to XPS spectrogram analysis, the content of Cr(III) in the reaction product was 2.1 times of Cr(VI), indicated that the reduction effect was greater than the adsorption effect in the process of Cr(VI) removal. The experiment proved that nZVI@Bent can effectively remove Cr(VI) from soil suspension, and can provide technical support for repairing Cr(VI)-polluted paddy fields. Chromium (Cr) is a heavy metal element that exists on the earth, mostly in the two valence states of Cr(III) and Cr(VI). Under certain conditions, Cr(VI) will be reduced to Cr(III) by reducing substances in the soil. Different environmental pollution effects of chromium in different valence states. Cr(VI) can be inhaled with dust to cause respiratory diseases. Oral administration can also cause digestive tract corrosion. After long-term exposure to the high concentration of Cr(VI), gene expression may be changed by destroying DNA, protein and lipid, which can cause cancer in severe cases 1,2. However, the toxicity of Cr(III) is much lower than that of Cr(VI), moreover, Cr(III) was an essential trace element in biological activities, and low concentration of Cr(III) was beneficial to organisms 3-6. Compared with Cr(VI), Cr(III) is more stable in the environment and difficult to migrate. Many industries containing chromium pollution such as metallurgy, tannery and electroplating and so on had sprung up in recent years. The discharge of wastewater in these industries lead to increasing the concentration of chromium in the cultivated soil environment, meanwhile, the land near factories was also polluted by a large accumulation of chromium slag and chromium dust 7-9. It is almost impossible to remove Cr from the soil, so it is the

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Nanoscale zero-valent iron@mesoporous hydrated silica core-shell particles with enhanced dispersibility, transportability and degradation of chlorinated aliphatic hydrocarbons

Cited by 59 publications

References 49 publications

Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

Effect of Flow Rate and Particle Concentration on the Transport and Deposition of Bare and Stabilized Zero-Valent Iron Nanoparticles in Sandy Soil

Preparation of Biomass Activated Carbon Supported Nanoscale Zero-Valent Iron (Nzvi) and Its Application in Decolorization of Methyl Orange from Aqueous Solution

Study on influencing factors and mechanism of removal of Cr(VI) from soil suspended liquid by bentonite-supported nanoscale zero-valent iron

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