Removal of Cr(VI) species from water with a newly-designed adsorptive treatment train

Ma, Ji; Liu, Chunting; Chen, Kezheng

doi:10.1016/j.seppur.2019.116041

Cited by 9 publications

(3 citation statements)

References 37 publications

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“…Currently, researchers at home and abroad have proposed a variety of methods to remove Cr(VI) from wastewater, mainly including chemical reduction precipitation, adsorption, ion exchange resin method, solvent extraction, membrane separation, etc. [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Rapid Removal of Cr(VI) from Wastewater by Surface Ionized Iron-Based MOF: Ion Branching and Domain-Limiting Effects

Wang,

Chen,

Yang

2023

Water

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Exploring the ratio of metal centers to organic ligands and the amount of DMF are important to improve the stability and adsorption efficiency of MOF materials as adsorbents. In this work, MIL101(Fe)-Na2CO3 was successfully obtained by modification with formic acid, sodium carbonate, carbon nanotubes, and moieties. The adsorption efficiency of MIL-101(Fe) on Cr(VI) was greatly improved, and the removal efficiency was able to reach 100% in 20 min with a maximum adsorption capacity of 20 mg/g. The inhibition order of the competing anions for the removal of hexavalent chromium was as follows: Cl− < NO3− < SO42−. The analysis of the adsorption thermodynamic model found that the adsorption of MIL101(Fe)-Na2CO3 for Cr(VI) showed spontaneous heat-absorbing and entropy-increasing chemisorption behavior. When using NaOH as the eluent and HCl as the regeneration stabilizer, MIL-101(Fe)-Na2CO3 had good adsorption capacity in multiple cycles.

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Section: Introductionmentioning

confidence: 99%

Rapid Removal of Cr(VI) from Wastewater by Surface Ionized Iron-Based MOF: Ion Branching and Domain-Limiting Effects

Wang,

Chen,

Yang

2023

Water

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“…The excessive discharge of various pollutants has caused serious environmental problems, especially water pollution. , Cr(VI) with a strict emission standard (≤0.05 mg L –1 ) , has received great attention because its toxicity is more than thousands of times that of Cr(III) ions . The reduction transformation of Cr(VI) to Cr(III) is considered to be an effective approach to reduce its toxicity. , For the purpose of Cr(VI) reduction, the addition of reducing substances such as Na 2 S 2 O 5 and Na 2 SO 3 is necessary to provide electrons for Cr(VI) in traditional treatment processes, which can accelerate Cr(III) generation and removal. − However, the oxidation capacity of Cr(VI) in wastewater is worthlessly consumed by additional reducing agents, resulting in the waste of Cr(VI) oxidizability and the consumption of more chemicals. Of particular note is that some organic substances (e.g., bisphenol A (BPA), organic acid) also coexist in Cr(VI)-containing wastewater, , which may serve as an electron donor for Cr(VI) reduction.…”

Section: Introductionmentioning

confidence: 99%

Insight into the Key Role of Cr Intermediates in the Efficient and Simultaneous Degradation of Organic Contaminants and Cr(VI) Reduction via g-C₃N₄-Assisted Photocatalysis

Zhang

Lan

Cui

et al. 2022

Environ. Sci. Technol.

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Photocatalysis provides an impetus for the synergetic removal of Cr(VI) and organic contaminants, but the generation of Cr intermediates and their potential oxidizability may be overlooked in pollutant conversion. Herein, the Cr intermediates in the Cr(VI) reduction process were emphasized in Cr(VI)/bisphenol A (BPA) by using graphitic carbon nitride as a photocatalyst. The active species for BPA photodegradation in the BPA system and Cr(VI)/BPA system suggested that the Cr(VI) reduction process indeed promotes BPA photodegradation. Electron paramagnetic resonance (EPR) of Cr complexes and in situ variable-temperature EPR analysis demonstrated Cr(V) intermediate (g = 1.978) generation in Cr(VI) reduction and its oxidization for BPA degradation in photocatalysis. By adding the electron donor Na2SO3, BPA degradation was induced in Cr(VI)/BPA solution, further confirming the positive effect of Cr(V). Moreover, the difference in BPA degradation products in the BPA/air, Cr(VI)/BPA/air, and Cr(VI)/BPA/Ar systems indirectly explained why the Cr(V) intermediate was involved in BPA degradation. Density functional theory calculations revealed that photogenerated electrons can reduce the free energy (0.98 eV) of converting Cr(VI) into Cr(V), which can facilitate the subsequent Cr(V) oxidation step for BPA degradation. This work contributes to the exploration of the Cr(VI) reduction process and the synergistic removal of organic pollutants in Cr(VI)/organics systems.

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“…Adsorption techniques are, therefore, widely used in domestic sewage treatment. Among the many types of available adsorbents, the most common include multiwalled carbon nanotubes (MWCNTs), diatomites, activated carbon, and biomass adsorbents . MWCNTs have attracted much attention because of their super-high strength, ductility, large specific surface areas, and complex pore structures. , However, MWCNTs have some limitations.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Separation of Cr(VI) from a Water Phase Using Multiwalled Carbon Nanotube-Immobilized Ionic Liquids

Sun

Wang

et al. 2020

ACS Omega

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Three types of multiwalled carbon nanotubes (MWCNTs, MWCNTs-OH, and MWCNTs-COOH) were used as carriers and five types of ionic liquids (ILs) were immobilized on each carrier by an impregnation method. Boehm titration, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, specific surface area analysis by the Brunauer–Emmett–Teller method, and thermogravimetric analysis were performed to investigate [C4mim]HSO 4 adsorption by the MWCNTs. The MWCNT-immobilized IL was used for Cr(VI) removal from a water phase. The adsorption properties of MWCNTs-COOH-immobilized [C4mim]HSO 4 were investigated by single-factor analysis. The results showed that the Cr(VI) removal rate was 52.14% and the adsorption capacity was 31.29 mg/g. The optimum adsorption conditions were as follows: initial Cr(VI) concentration, 60 mg/L; adsorbent dosage, 50 mg; pH 2.0; adsorption temperature 40 °C; and adsorption time, 200 min. Adsorption isotherm data fitted the Freundlich model, which indicates that the adsorption process was in line with the multimolecular layer adsorption theory. The Cr(VI) adsorption behaviors of the three adsorbents were consistent with a pseudo-second-order dynamic model. Thermodynamic analysis of the reaction systems was also performed. The Cr(VI) removal rates of MWCNTs-3, MWCNTs-OH-3, and MWCNTs-COOH-3 were 27.97, 9.39, and 7.34% lower than the initial removal rates after five cycles.

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Removal of Cr(VI) species from water with a newly-designed adsorptive treatment train

Cited by 9 publications

References 37 publications

Rapid Removal of Cr(VI) from Wastewater by Surface Ionized Iron-Based MOF: Ion Branching and Domain-Limiting Effects

Rapid Removal of Cr(VI) from Wastewater by Surface Ionized Iron-Based MOF: Ion Branching and Domain-Limiting Effects

Insight into the Key Role of Cr Intermediates in the Efficient and Simultaneous Degradation of Organic Contaminants and Cr(VI) Reduction via g-C₃N₄-Assisted Photocatalysis

Adsorption Separation of Cr(VI) from a Water Phase Using Multiwalled Carbon Nanotube-Immobilized Ionic Liquids

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Removal of Cr(VI) species from water with a newly-designed adsorptive treatment train

Cited by 9 publications

References 37 publications

Rapid Removal of Cr(VI) from Wastewater by Surface Ionized Iron-Based MOF: Ion Branching and Domain-Limiting Effects

Rapid Removal of Cr(VI) from Wastewater by Surface Ionized Iron-Based MOF: Ion Branching and Domain-Limiting Effects

Insight into the Key Role of Cr Intermediates in the Efficient and Simultaneous Degradation of Organic Contaminants and Cr(VI) Reduction via g-C3N4-Assisted Photocatalysis

Adsorption Separation of Cr(VI) from a Water Phase Using Multiwalled Carbon Nanotube-Immobilized Ionic Liquids

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Insight into the Key Role of Cr Intermediates in the Efficient and Simultaneous Degradation of Organic Contaminants and Cr(VI) Reduction via g-C₃N₄-Assisted Photocatalysis