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13 pages, 1616 KiB

Open AccessArticle

Accumulation of Vanadium by Nanoscale Zero-Valent Iron Supported by Activated Carbon under Simulation Water Conditions: A Batch Study

by Qiang Huang, Shuai Fu, Huijie Zhu, Huaihui Song, Zhe Yang, Xiuji Zhang, Junhong Bie, Jianhong Lu, Mingyan Shi and Bo Liu

Water 2022, 14(18), 2867; https://doi.org/10.3390/w14182867 - 14 Sep 2022

Cited by 1 | Viewed by 2051

Abstract

Vanadium (V(V)) removal from simulation water (SW) was successfully accomplished using nanoscale zero-valent iron that was immobilized by activated carbon (NZVI/AC) which was used as an adsorbent. We investigated the effects of different parameters on V(V) removal, such as pH, dissolved oxygen (DO), common ions and adsorption kinetics for SW. The intraparticle diffusion model fits this study well (R² > 0.9) according to the results of the kinetics investigation which showed that the adsorption of vanadium by NZVI/AC was rapid in the first 12 h and that equilibrium was reached in about 72 h. The amount of V(V) that was removed from the solution increased when it was subjected to pH 2 to pH 8, and this decreased after pH 8. While the effects of other anions and humic acid were negligible, the elimination of V(V) was significantly reduced by using phosphate and silicate. Fe²⁺ and Al³⁺, two common metal cations, improved the V(V) adsorption. High oxygen levels impeded the vanadium elimination, while anoxic conditions encouraged it. Elution with 0.1 M NaOH can be used to renew NZVI/AC in an efficient manner. Full article

(This article belongs to the Section Wastewater Treatment and Reuse)

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12 pages, 1355 KiB

Open AccessArticle

Removal of Molybdenum(VI) from Raw Water Using Nano Zero-Valent Iron Supported on Activated Carbon

by Huijie Zhu, Qiang Huang, Shuai Fu, Xiuji Zhang, Mingyan Shi and Bo Liu

Water 2020, 12(11), 3162; https://doi.org/10.3390/w12113162 - 12 Nov 2020

Cited by 12 | Viewed by 3638

Abstract

Traces of Molybdenum (Mo) in drinking water pose potent dangers owing to its harmful effects on the health of humans. This study used nanoscale zero-valent iron (Fe⁰) supported by activated carbon (NZVI/AC) for removing Mo(VI) from raw water. In an attempt to gain an understanding of the various factors that affect the process, we designed the study to look into the impact of various experimental parameters including pH, adsorption kinetics, and coexisting ions on the Mo(VI) removal using fixed-bed column runs and a batch-adsorption method and for Mo(VI) removal using NZVI/AC. The optimum conditions were found to be pH 4.5 and an equilibrium time of 9 h and 72 h for simulation water (SW) and raw water (RW), respectively. The removal of Mo(VI) was remarkably inhibited by the presence of silicate (

{SiO}_{4}^{2 -}

) and phosphate (

{PO}_{4}^{3 -}

), while the impact of humic acid and some other anions was insignificant. Metal cations such as Fe³⁺, Al³⁺, Zn²⁺, and Ni²⁺ enhanced the adsorption of Mo(VI). The influent contaminant concentration Mo(VI) in raw water was found to be 0.1603 mg/L, the empty-bed contact time (EBCT) was 3 and 6 min, whereas the breakthrough empty-bed volumes were 800 and 1100 and at the value of 70 μg/L provided by WHO provisional guidelines, respectively. Full article

(This article belongs to the Special Issue Advances in Wastewater Treatment Processes)

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12 pages, 4386 KiB

Open AccessArticle

Adsorption Kinetics of Arsenic (V) on Nanoscale Zero-Valent Iron Supported by Activated Carbon

by Huijie Zhu, Mingyan Shi, Xiuji Zhang, Bo Liu and Dahu Yao

Nanomaterials 2020, 10(9), 1791; https://doi.org/10.3390/nano10091791 - 9 Sep 2020

Cited by 22 | Viewed by 3152

Abstract

The presence of arsenic (As) in drinking water is of serious concern due to its negative impact on human health. This work reports on the kinetics of nanoscale zero-valent iron (Fe⁰) supported by activated carbon (NZVI/AC) for the removal of As (V) species from aqueous solutions. To better understand the factors affecting this process, we investigated the effects of various experimental parameters including initial As (V) concentration, adsorbent dosage, pH, temperature, and coexisting ions on the adsorption kinetics using a batch-adsorption method. The optimum conditions for As (V) removal by NZVI/AC were found to be: 318 K, pH 3.5, an adsorbent dosage of 1.5 g/L, and an equilibrium time of 72 h. A greater mass of NZVI/AC, lower concentration of As (V) and lower pH positively promoted adsorption kinetics. The presence of phosphate (

{PO}_{4}^{3 -}

) and silicate (

{SiO}_{4}^{2 -}

) markedly inhibited As (V) removal kinetics. However, in the presence of 4.5 g/L NZVI/AC, ≥99.9% of As (V) was removed from raw groundwater. Full article

(This article belongs to the Special Issue Nanomaterials and Nanotechnology in Wastewater Treatment)

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