Activated carbon impregnated by zero-valent iron nanoparticles (AC/nZVI) optimized for simultaneous adsorption and reduction of aqueous hexavalent chromium: Material characterizations and kinetic studies

Mortazavian, Soroosh; An, Hyeunhwan; Chun, Dong Won; Moon, Jaeyun

doi:10.1016/j.cej.2018.07.170

Cited by 213 publications

(62 citation statements)

References 71 publications

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“…In order to address these drawbacks, researchers have attempted to stabilize and disperse NZVI particles with the following method: 1) offering a support for NZVI particles, such as kaolinite [17], bentonite [18], activated carbon [19,20], mesoporous carbon [21], and mesoporous silica [22]; 2) changing the surface properties of NZVI with surfactant [23], polyelectrolyte, or nature biopolymer [24]. Most solid supports cannot be used to control stability and nanometer distribution of the NZVI particles.…”

Section: Introductionmentioning

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: Introductionmentioning

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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“…Therefore, the removal of Cr(VI) by nZVI-ASBC is in accordance with the pseudo second-order dynamic model. The removal yield of Cr(VI) by nZVI-ASBC depends on the concentrations of Cr ions and the adsorbent [30]. Moreover, k = 0.1544 can be obtained, which indicates that the reaction rate of the adsorption was 0.5365 mg•g −1 min −1 by calculation.…”

Section: Kinetics Of Cr(vi) Removalmentioning

confidence: 83%

“…The orthogonal experiment, L25 (1 5 × 1 4 × 1 5 ), involved three factors, namely, the temperature, pH, and initial concentration of Cr(VI). The temperature included three parallels (283, 288, 293, 298, and 303 K), pH included five parallels (pH = 3, 5, 7, 9, 11), and the initial concentration of Cr(VI) included four parallels (10,20,30, and 40 mg•L −1 ). SPSS software was used to design and analyze the orthogonal experiments.…”

Section: Orthogonal Experimental Design and Statistical Analysismentioning

confidence: 99%

Almond Shell-Derived, Biochar-Supported, Nano-Zero-Valent Iron Composite for Aqueous Hexavalent Chromium Removal: Performance and Mechanisms

Shu

Cui

et al. 2020

Nanomaterials

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Nano-zero-valent iron biochar derived from almond shell (nZVI-ASBC) was used for hexavalent chromium (CR) removal. Experiments showed that pH was the main factor (p < 0.01) that affected the experimental results. At a dosage of 10 mg·L−1 and pH of 2–6, in the first 60 min, nZVI-ASBC exhibited a removal efficiency of 99.8%, which was approximately 20% higher than the removal yield at pH 7–11. Fourier transform infrared spectroscopy results indicated N-H was the main functional group that influenced the chemisorption process. The pseudo second-order dynamics and Langmuir isotherm models proved to be the most suitable. Thermodynamic studies showed that the reaction was exothermic and spontaneous at low temperatures (T < 317 K). Various interaction mechanisms, including adsorption and reduction, were adopted for the removal of Cr(VI) using the nZVI-ASBC composite. The findings showed that the BC-modified nZVI prepared with almond shell exerts a good effect and could be used for the removal of Cr(VI).

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“…The following are available online at http://www.mdpi.com/1420-3049/25/1/47/s1, Figures S1-S6, Tables S1 and S2 [11,26,33,48,49,[55][56][57][58][59][60][61][62].…”

Section: Supplementary Materialsmentioning

confidence: 99%

Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater

et al. 2019

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Nanometer zero-valent iron (nZVI) has been widely used in the treatment of heavy metals such as hexavalent chromium (Cr(VI)). A novel composite of bead string-structured nZVI on modified activated carbon (nZVI-MAC) is prepared here, using polyethylene glycol as the stable dispersant rather than traditional ethanol during the loading process. The microstructure characterization shows that nZVI particles are loaded on MAC with a bead string structure in large quantity and stably due to the addition of hydroxyl functional groups on the surface by polyethylene glycol. Experiments on the treatment of Cr(VI) in wastewater show that the reaction process requires only 20 min to achieve equilibrium. The removal rate of Cr(VI) with a low concentration (80-100 mg/L) is over 99% and the maximum saturation removal capacity is up to 66 mg/g. The system converts Cr(VI) to trivalent chromium (Cr(III)) through an oxidation-reduction effect and forms an insoluble material with iron ions by coprecipitation, which is then adsorbed on the surface of the nZVI-MAC. The process conforms to the quasi-second order adsorption kinetics equation (mainly chemical adsorption process).

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Activated carbon impregnated by zero-valent iron nanoparticles (AC/nZVI) optimized for simultaneous adsorption and reduction of aqueous hexavalent chromium: Material characterizations and kinetic studies

Cited by 213 publications

References 71 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

Almond Shell-Derived, Biochar-Supported, Nano-Zero-Valent Iron Composite for Aqueous Hexavalent Chromium Removal: Performance and Mechanisms

Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater

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