Removal of hexavalent chromium from groundwater using sodium alginate dispersed nano zero-valent iron

Li, Zihan; Xu, Shaofa; Xiao, Guanghui; Li-min, Qian; Song, Yun

doi:10.1016/j.jenvman.2019.04.130

Cited by 80 publications

(19 citation statements)

References 45 publications

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“…Settling rate constants (k) and settled fractions (F) in the rapid and slow compartments of particle sedimentation, calculated from the biphasic rate model (R 2 > 0.9). Zeta potential is a key index of the stability of NZVI and a higher absolute value indicates more stability [37]. Zeta potentials of F-NZVI with different mass ratios are listed in Table 2.…”

Section: Sedimentation Test Of F-nzvi Particles With Different Mass Rmentioning

confidence: 99%

The Influence of Pluronic F-127 Modification on Nano Zero-Valent Iron (NZVI): Sedimentation and Reactivity with 2,4-Dichlorophenol in Water Using Response Surface Methodology

Zhang

Jing

et al. 2020

Catalysts

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Nano zero-valent iron (NZVI) is widely used for reducing chlorinated organic pollutants in water. However, the stability of the particles will affect the removal rate of the contaminant. In order to enhance the stability of nano zero-valent iron (NZVI), the particles were modified with F-127 as an environmentally friendly organic stabilizer. The study investigated the effect of the F-127 mass ratio on the colloidal stability of NZVI. Results show that the sedimentation behavior of F-NZVI varied at different mass ratios. A biphasic model was used to describe the two time-dependent settling processes (rapid sedimentation followed by slower settling), and the settling rates were calculated. The surface morphology of the synthesized F-NZVI was observed with a scanning electron microscope (SEM), and the functional groups of the samples were analyzed with Fourier Transform Infrared Spectroscopy (FTIR). Results show that the F-127 was successfully coated on the surface of the NZVI, and that significantly improved the stability of NZVI. Finally, in order to optimize the removal rate of 2,4-dichlorophenol (2,4-DCP) by F-NZVI, three variables were tested: the initial concentration 2,4-DCP, the pH, and the F-NZVI dosage. These were evaluated with a Box-Behnken Design (BBD) of response surface methodology (RSM). The experiments were designed by Design Expert software, and the regression model of fitting quadratic model was established. The following optimum removal conditions were determined: pH = 5, 3.5 g·L−1 F-NZVI for 22.5 mg·L−1 of 2,4-DCP.

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Section: Sedimentation Test Of F-nzvi Particles With Different Mass Rmentioning

confidence: 99%

The Influence of Pluronic F-127 Modification on Nano Zero-Valent Iron (NZVI): Sedimentation and Reactivity with 2,4-Dichlorophenol in Water Using Response Surface Methodology

Zhang

Jing

et al. 2020

Catalysts

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“…For nZVI, its mobility in quartz sand column is very low, only <0.05 when it reaches the plateaus (Figure 4a). This may be due to the aggregation of nZVI in solution, which leads to the increase of particle size and the decline of mobility of nanoparticles [53]. In addition, in this experiment, the zeta potential of nZVI is positive and its surface is positively charged, while the zeta potential of quartz sand is negative and its surface is negatively charged (Table S2).…”

Section: Transport Of Nzvi and B-nzvi In Quartz Sand Columnsmentioning

confidence: 80%

Nanoscale Zero-Valent Iron Modified by Bentonite with Enhanced Cr(VI) Removal Efficiency, Improved Mobility, and Reduced Toxicity

Luo

Sun

et al. 2021

Nanomaterials

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The aggregation of nanoscale zero-valent iron (nZVI) particles and their limited transport ability in environmental media hinder their application in environmental remediation. In this study, the Cr(VI) removal efficiency, transport performance, and toxicity of nZVI and bentonite-modified nZVI (B-nZVI) were investigated. Compared with nZVI, B-nZVI improved the removal efficiency of Cr(VI) by 10%, and also significantly increased the transport in quartz sand and soil. Increasing the flow rate can enhance the transport of nZVI and B-nZVI in the quartz sand columns. The transport of the two materials in different soils was negatively correlated with the clay composition. Besides, modification of nZVI by bentonite could reduce toxicity to luminous bacteria (Photobacterium phosphereum T3) and ryegrass (Lolium perenne L.). Compared with Fe-EDTA, the transfer factors of nZVI and B-nZVI were 65.0% and 66.4% lower, respectively. This indicated that although iron nanoparticles accumulated in the roots of ryegrass, they were difficult to be transported to the shoots. The results of this study indicate that B-nZVI has a strong application potential in in situ environmental remediation.

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“…Two distinct peaks of Cr 2 O 3 (577.17 eV) and Cr(OH) 3 (586.76 eV) can be observed in the reaction product of Cr(III) and nZVI/PBC. It indicated that nZVI/PBC removed Cr(III) and formed Cr 2 O 3 and Cr(OH) 3 precipitates 43 . The characteristic peaks at 933.16 eV (Cu 2p 3/2) and 952.80 eV (Cu 2p 1/2) represented Cu 0 /Cu 2 O, while the characteristic peaks at 938.6 eV (Cu 2p 3/2) and 942.50 eV (Cu 2p 1/2) corresponded to Cu(II) 44 .…”

Section: Resultsmentioning

confidence: 99%

High‐efficiency adsorption of various heavy metals by tea residue biochar loaded with nanoscale zero‐valent iron

Liu

Zhang

Fan

et al. 2021

Env Prog and Sustain Energy

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Nanoscale zero‐valent iron (nZVI) loaded on tea residue biochar activated with phosphoric acid composites was synthesized. This adsorbent can efficiently adsorb multiple heavy metal ions such as Pb (II), Cr (III), Cu (II), and Ni (II) simultaneously. The adsorption process was found to follow the pseudo‐second‐order kinetic model. Equilibrium adsorption capacities reached 288.18, 162.34, 242.72, and 267.22 mg·g−1 for Pb(II), Cr(III), Cu(II), and Ni(II), respectively. The common interfering ions exhibited lower influence on its adsorption capacity. The adsorption mechanism includes reduction, ion exchange, surface complexation and precipitation. Furthermore, the waste adsorbent was converted into a catalyst in situ, which could catalyze the degradation of Congo red by establishing an electron transfer pathway. This research provides a new concept for the sustainable utilization of industrial tea residues and the harmless treatment of waste nZVI composite adsorbents.

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Removal of hexavalent chromium from groundwater using sodium alginate dispersed nano zero-valent iron

Cited by 80 publications

References 45 publications

The Influence of Pluronic F-127 Modification on Nano Zero-Valent Iron (NZVI): Sedimentation and Reactivity with 2,4-Dichlorophenol in Water Using Response Surface Methodology

The Influence of Pluronic F-127 Modification on Nano Zero-Valent Iron (NZVI): Sedimentation and Reactivity with 2,4-Dichlorophenol in Water Using Response Surface Methodology

Nanoscale Zero-Valent Iron Modified by Bentonite with Enhanced Cr(VI) Removal Efficiency, Improved Mobility, and Reduced Toxicity

High‐efficiency adsorption of various heavy metals by tea residue biochar loaded with nanoscale zero‐valent iron

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