Removal of low concentration Cr(VI) from aqueous solution by magnetic-fluids fixed bed using the high gradient magnetic separation

Wang, Qiang; Guan, Yong; Ren, Xiaopeng; Yang, Ming; Liu, Xiang

doi:10.1016/j.jcis.2012.02.001

Cited by 19 publications

(7 citation statements)

References 42 publications

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“…Movement of magnetic nanoparticles in response to external magnetic field is a working mechanism in the magnetic separation. Magnetic field gradient greater than 10 3 T/m is applied for the fast and efficient movement of particles in the separation technology . Such high field gradients are generated by distorting magnetic fields with magnetizable materials like steel wool fiber.…”

Section: Introductionmentioning

confidence: 99%

Agglomeration Dynamics of Magnetite Nanoparticles at Low Magnetic Field Gradient

Jin

Kim

2018

Bulletin Korean Chem Soc

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Agglomeration of magnetite nanoparticles in the aqueous solution is studied at the low magnetic field gradients of 23-34 T/m by monitoring the temporal change of magnetic weight. A conventional electronic balance is used to measure the magnetic weight that is the magnetic force on the magnetic sample by the magnetic field gradient. The magnetic weight grows slowly following the stretched exponential after the instantaneous jump by the Neel and Brown relaxation. Magnetization of the magnetite nanoparticles is estimated from the magnetic weight and compared with the Langevin function. The magnetization is close to the saturation in the studied magnetic field range and the saturation magnetization of the agglomerate of nanoparticles is about 60% of that of the bulk magnetite. Kinetic parameters of the stretched exponential show little the magnetic field dependence in the investigated range. Complex energy landscape is involved in the agglomeration as the stretched exponential dynamics indicates. The half-life of the response function for the magnetic weight change suggests that the pathways of low energy barriers are activated by magnetic field at the early stage of agglomeration.

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Section: Introductionmentioning

confidence: 99%

Agglomeration Dynamics of Magnetite Nanoparticles at Low Magnetic Field Gradient

Jin

Kim

2018

Bulletin Korean Chem Soc

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“…For example, solvent extraction method could bring in organic pollutants, sulfide precipitator as common precipitator may be residual and generate hydrogen sulfide (H 2 S). In general, conventional techniques are either low efficiency or cost too much when they are applied to low Cr(VI) concentration in wastewater (Wang et al 2012a ; Huang and Huang 1996 ).…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal derived nitrogen doped SrTiO3 for efficient visible light driven photocatalytic reduction of chromium(VI)

et al. 2016

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In this work, we report on the synthesis of nitrogen doped SrTiO3 nanoparticles with efficient visible light driven photocatalytic activity toward Cr(VI) by the solvothermal method. The samples are carefully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–Vis diffuse reflectance spectroscopy and photocatalytic test. It is found that nitrogen doping in SrTiO3 lattice led to an apparent lattice expansion, particle size reduction as well as subsequent increase of Brunner–Emmet–Teller surface area. The visible light absorption edge and intensity can be modulated by nitrogen doping content, which absorption edge extends to about 600 nm. Moreover, nitrogen doping can not only modulate the visible light absorption feature, but also have consequence on the enhancement of charge separation efficiency, which can promote the photocatalytic activity. With well controlled particle size, Brunner–Emmet–Teller surface area, and electronic structure via nitrogen doping, the photocatalytic performance toward Cr(VI) reduction of nitrogen doped SrTiO3 was optimized at initial hexamethylenetetramine content of 2.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2804-2) contains supplementary material, which is available to authorized users.

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“…In addition, this treatment highly depends on the pH level, which is quite challenging to maintain for treating raw wastewater (Kace & Linford, 1975). Recently, the separation by magnetic force has gained attention due to its capability to remove particles efficiently, cost-efficient technology, and adequate to treat a high volume of wastewater within a short time (Zhou et al, 2009;Wang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Optimization and Modelling of Turbidity Removal of Sewage using High-Gradient Magnetic Separation (HGMS) by Response Surface Methodology (RSM)

Supian¹,

Sohaili²,

Zon³

2020

JST

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Endless industrial development and growing society occasionally create an enormous volume of wastewater, which leads to some issues on wastewater treatment. Existing conventional screening processes have various limitations and drawbacks. Therefore, this study investigated the use of a combination of non-corrosive stainless steel wool and a permanent magnet to increase magnetic gradient, hence reducing suspended matter in sewage through turbidity test. An approach for optimizing the reduction of suspended matter through turbidity analysis was conducted using central composite design (CCD) under response surface methodology (RSM). Three critical independent variables, such as magnet strength, circulation time, and steel wool, and turbidity removal as the response, were further studied to analyze their interaction effects. As a result, an optimal value of turbidity removal was found at 90.3% under the specified optimum conditions of magnet strength of 245 mT, 116 g of non-corrosive stainless steel wool, and 16 h of circulation time. Statistical analysis had shown that the magnet strength, circulation time, and steel wool significantly affected the turbidity removal performance. Furthermore, design of experiment was significantly verified by a small range of error between predicted and actual data. Consequently, a higher gradient of magnetic separation was proven to effectively remove suspended matter using inexpensive non-corrosive stainless steel wool without using magnetic adsorbent. Thus, the suggested approach was found to be cost-effective and environmentally friendly for sewage treatment.

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Removal of low concentration Cr(VI) from aqueous solution by magnetic-fluids fixed bed using the high gradient magnetic separation

Cited by 19 publications

References 42 publications

Agglomeration Dynamics of Magnetite Nanoparticles at Low Magnetic Field Gradient

Agglomeration Dynamics of Magnetite Nanoparticles at Low Magnetic Field Gradient

Hydrothermal derived nitrogen doped SrTiO3 for efficient visible light driven photocatalytic reduction of chromium(VI)

Optimization and Modelling of Turbidity Removal of Sewage using High-Gradient Magnetic Separation (HGMS) by Response Surface Methodology (RSM)

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