Soaked Al powder for efficient reduction of hexavalent chromium in neutral solution

Peng, Tao; Guo, Xiao-Han; Yang, Yang; Gai, Wei‐Zhuo; Deng, Zhen‐Yan

doi:10.1016/j.jclepro.2022.132901

Cited by 6 publications

(6 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, there is an induction time for the beginning of Al-water reaction in neutral aqueous solution, which results from the hydration process of the Al surface passive oxide film. ,,, In this work, a soaking procedure was used to activate Al powder so that Al particle surfaces were covered by a layer of fine nanometer Al(OH) 3 particles. This layer of fine Al(OH) 3 particles is porous (Figure b,d) and has low tensile strength so that outside ions and molecules can contact and react with inner Al more easily, leading to shorter induction time for the beginning of Al-water reaction, which was confirmed by many of previous works ,,, and also by this work shown in Figure . The Al surface modification method was successfully used to speed up Al-water reaction to generate hydrogen, and its detailed mechanisms are discussed in previous works. , Figure indicates that the induction time for the beginning of Al-water reaction using soaked Al powder is much shorter than that using pristine Al powder, and nitrate in aqueous solution promotes Al-water reaction as well due to its weak alkalinity …”

Section: Resultssupporting

confidence: 81%

“…After soaking, the dense passive oxide film on pristine Al particles became loose, and there was a layer of fine flocculent particles on soaked Al particle surfaces (Figure b,d), because the passive oxide film on pristine Al particle surfaces underwent a hydration reaction during the soaking process. , The fine flocculent particles on soaked Al surfaces are crystallized aluminum hydroxides with the sizes of a few nanometers (arrows in Figure e), which are a bayerite (Al(OH) 3 ) phase confirmed by their X-ray diffraction patterns shown in Figure . The thickness of the crystallized aluminum hydroxides on soaked Al particles can be up to ∼1 μm for a soaking time of ∼35 h …”

Section: Resultsmentioning

confidence: 99%

“…The soaked Al suspension was centrifuged for 10 min using a centrifuger (TDL-5-A, Anting Scientific Instrument Factory, China), then the up-layer water was removed, and a concentrated Al slurry was obtained. The concentrated Al slurry was sent for freeze-drying for 24 h using a freeze-dryer (Scientz-10nd, Ningbo Xinzhi Co., China) to obtain the soaked Al powder . Before the nitrate reduction, the soaked Al powder was sieved with a 100-mesh sieve.…”

Section: Methodsmentioning

confidence: 99%

“…The concentrated Al slurry was sent for freeze-drying for 24 h using a freeze-dryer (Scientz-10nd, Ningbo Xinzhi Co., China) to obtain the soaked Al powder. 41 Before the nitrate reduction, the soaked Al powder was sieved with a 100-mesh sieve.…”

Section: Methodsmentioning

confidence: 99%

“…47,48 The fine flocculent particles on soaked Al surfaces are crystallized aluminum hydroxides with the sizes of a few nanometers (arrows in Figure 1e), which are a bayerite (Al(OH) 3 ) phase confirmed by their X-ray diffraction patterns shown in Figure 2. The thickness of the crystallized aluminum hydroxides on soaked Al particles can be up to ∼1 μm for a soaking time of ∼35 h. 41 3.2. Nitrate Removal.…”

Section: Characterizationmentioning

confidence: 99%

See 4 more Smart Citations

Efficient Removal of Nitrate in Neutral Solution Using Zero-Valent Al Activated by Soaking

Dai

Guo

et al. 2023

ACS Omega

Self Cite

View full text Add to dashboard Cite

Nitrate is a contaminant widely found in surface water, and a high concentration of nitrate can pose a serious threat to human health. Zero-valent iron is widely used to reduce nitrate in aqueous solution, but an acidic condition is required. Zero-valent aluminum has a much lower redox potential (E 0(Al3+/Al0) = −1.662 V) than zero-valent iron (E 0(Fe2+/Fe0) = −0.44 V), making it a better choice for reduction of nitrate. However, a passive oxide film covering on Al surfaces inhibits its electron transfer. In this work, metal Al powder was activated by a soaking procedure in deionized water. It was found that nitrate in neutral solution can be efficiently and completely reduced by soaked Al, even if the concentration of nitrate-N was up to 100 mg L–1. Using an optimal soaking time, the soaked Al can remove >90% of nitrate in aqueous solution within ∼2 h at 50 °C. Furthermore, the nitrate reduction efficiency increased with increasing reaction temperature and dosage of Al powder. After reaction, only ∼50% of pristine N content was left in the form of ammonia ions (NH4 +) in aqueous solution. Mechanism analyses showed that after soaking, Al particle surfaces were covered by a layer of loose and fine Al(OH)3 grains, which can shorten the induction time for the beginning of the reaction between inner Al and outside ions or molecules. This is the reason why soaked Al has a high efficiency for nitrate removal. The present results indicate that soaking is an effective way to activate Al to remove nitrate in water.

show abstract

Section: Resultssupporting

confidence: 81%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

See 3 more Smart Citations

Efficient Removal of Nitrate in Neutral Solution Using Zero-Valent Al Activated by Soaking

Dai

Guo

et al. 2023

ACS Omega

Self Cite

View full text Add to dashboard Cite

show abstract

Novel Preparation of Two Oxidized Starch Formulations for Removal of Cr (VI) Ions From an Aqueous Solution

Qin,

Wang,

Zhang

et al. 2024

Starch Stärke

View full text Add to dashboard Cite

Hexavalent chromium (Cr(VI)) has attracted much attention because it is a harmful pollutant. In this study, acid hydrolyzed hydrothermal double modified starch (AHS) and hydroperoxide oxidized starch (HOS) are prepared from natural starch and used for the reduction of chromium (VI) in aqueous systems. The effects of hydrothermal acidolysis and oxidative modification of starch on the reduction rate of Cr(VI) are discussed, including the changes of solubility, swelling power, particle size, content of straight‐chain starch, and carbonyl/carboxylic group content. The results of response surface methodology (RSM) optimization show that the influence of reaction conditions on the reduction rate of Cr(VI) by NS is as follows: reaction time > initial pH of solution > reaction temperature > starch to Cr(VI) mass ratio; and on the reduction rate of Cr(VI) by AHS and HOS is as follows: initial pH of solution > reaction time > starch to Cr(VI) mass ratio > reaction temperature.

show abstract

Preparation of nano zero-valent aluminum for one-step removal of methylene blue from aqueous solutions: cost analysis for scaling-up and artificial intelligence

Sadek

Mostafa

2022

Appl Water Sci

View full text Add to dashboard Cite

Methylene blue (MB) is a heterocyclic aromatic dye that is difficult to biodegrade due to its complex chemical structure. In this study, chemically prepared nano zero-valent aluminum (nZVAl) was investigated for the first time for one-step removal of MB from aqueous solutions under different experimental factors (pH, dosage, time, MB concentration, stirring rate, temperature, detergents, and ionic strength). The prepared nZVAl material was characterized using XRD, TEM, SEM, EDS, and FTIR. Results indicated that at an initial MB concentration of 10 mg/L, pH 10, nZVAl dosage 1.0 g/L, stirring rate 200 rpm, and temperature 30 °C, the removal efficiency of approximately 99.0% was achieved within an equilibrium time of 90 min. An improvement in MB removal efficiency was observed in the presence of inorganic salts, while the presence of detergents resulted in a reduction in MB removal efficiency. The isotherm adsorption data were best fitted by the Freundlich isotherm model (R2: 0.9569), while the kinetic data were well described by the pseudo-second-order (PSO) model (R2: 0.9999). Based on the thermodynamic study, the MB adsorption process is physically diffusion-controlled. The adsorption of MB onto nZVAl was accurately described using an artificial neural network (ANN) with a structure of 11–10–1 and R2 of 0.97. The overall cost of scaling up the adsorption unit to be used for MB removal from aqueous solutions under the optimum conditions is about US$1.31/m3. Consequently, this study opens the door for other researchers to test nZVAl in treating real textile wastewater.

show abstract

Soaked Al powder for efficient reduction of hexavalent chromium in neutral solution

Cited by 6 publications

References 83 publications

Efficient Removal of Nitrate in Neutral Solution Using Zero-Valent Al Activated by Soaking

Efficient Removal of Nitrate in Neutral Solution Using Zero-Valent Al Activated by Soaking

Novel Preparation of Two Oxidized Starch Formulations for Removal of Cr (VI) Ions From an Aqueous Solution

Preparation of nano zero-valent aluminum for one-step removal of methylene blue from aqueous solutions: cost analysis for scaling-up and artificial intelligence

Contact Info

Product

Resources

About