The influence of the magnetic field on the crystallisation form of calcium carbonate and the testing of a magnetic water-treatment device

Kobe, Spomenka; Dražić, Goran; McGuiness, P.J.; Stražišar, J.

doi:10.1016/s0304-8853(01)00432-2

Cited by 94 publications

(57 citation statements)

References 10 publications

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“…Experiments were also performed in the laboratory to investigate the magnetic effects on CaCO 3 nucleation and crystal growth via a more systematic approach; however, conflicting results also exist in the literature. For example, the magnetic field would suppress (Dalas and Koutsoukos, 1989;Kobe et al, 2001), accelerate (Higashitani et al, 1993;Barrett and Parsons, 1998), or have no effect (Duffy, 1977;Hasson and Bramson, 1985) on the CaCO 3 growth, thus creating a widespread controversy as to the credibility of this type of water conditioning, such as the conclusion of Herzog et al (1989) that the effectiveness of a magnetic water treatment device was attributed to the contamination of solution by Fe ions, which dissolved from the device and inhibited the build-up of scale.…”

Section: Introductionmentioning

confidence: 99%

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Effects of magnetic field on the crystallization of CaCO3 using permanent magnets

Tai

Chang

2008

Chemical Engineering Science

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Section: Introductionmentioning

confidence: 99%

“…An additional drawback of some reported studies was measuring the deposit rate of scales on the pipe wall, which took a long time to collect any data, probably several weeks or months (Kobe et al, 2001). Recently, Tai et al (2008) investigated the effect of a magnetic field on the calcite growth rate in a constant-composition environment.…”

Section: Introductionmentioning

confidence: 99%

Effects of magnetic field on the crystallization of CaCO3 using permanent magnets

Tai

Chang

2008

Chemical Engineering Science

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“…Only 10 min of settling time was required to reach a maximal removal rate for different algae densities. The magnetic water treatment device has been applied in the practical water treatment (Kobea et al 2001;Smith et al 2003;Patent US4888113). This integration of nano-Fe 3 O 4 and PACl provides a potential application for fast algal removal of algae in reservoirs.…”

Section: Resultsmentioning

confidence: 99%

Removal of Microcystis aeruginosa using nano-Fe3O4 particles as a coagulant aid

Zhang

Jiang

Guo

et al. 2015

Environ Sci Pollut Res

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Blue-green algae bloom is of great concern globally since they adversely affect the water ecosystem and also drinking water treatment processes. This work investigated the removal of Microcystis aeruginosa (M. aeruginosa) by combining the conventional coagulant polyaluminum chloride (PACl) with nano-Fe3O4 particles as a coagulant aid. The results showed that the addition of nano-Fe3O4 significantly improved the removal efficiency of M. aeruginosa by reducing the amount of PACl dosage and simultaneously hastening the sedimentation. At the M. aeruginosa density of an order of magnitude of 10(7), 10(6), and 10(5) pcs/mL, respectively, the corresponding PACl dose of 200, 20, and 2 mg/L and the mass ratio of PACl to nano-Fe3O4 of 4:1, the removal efficiency of M. aeruginosa could be increased by 33.0, 44.7, and 173.1%, respectively. Compared to PACl, PACl combined with the nano-Fe3O4 as a coagulant aid had higher removal efficiency at a wider pH range. SEM images showed that nano-Fe3O4 first combined with PACl to form clusters and further generated the flocs with algae. Results from the laser particle analyzer further suggested that the floc size increased with the addition of nano-Fe3O4. It was noted that the addition of nano-Fe3O4 led to aluminum species change after PACl hydrolyzed in the algae solution, from Ala to Alb and Alc subsequently. As a coagulant aid, the nano-Fe3O4, in conjunction with PACl, apparently provided nucleation sites for larger flocs to integrate with M. aeruginosa. In addition, increased floc density improved the removal of M. aeruginosa.

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“…When water temperature increases, the solubility of calcium carbonate decreases (Young I. Cho et al, 2005;Coetzee, Yacoby, Howell, & Mubenga, 1998) and when dissolved or suspended minerals precipitate they are attracted to the membrane surface due to their natural charges (Bisbee, 2003;Thompson et al, 2012) and form crystals (Kobe, Dražić, McGuiness, & Stražišar, 2001). Scaling results in permeate flux decline and crystals can damage the active membrane layer (Valavala, Sohn, Han, Her3, & Yoon, 2011 ).…”

Section: Introductionmentioning

confidence: 99%

The influence of electromagnetic fields from two commercially available water-treatment devices on calcium carbonate precipitation

Piyadasa

Yeager

Gray

et al. 2017

Environ. Sci.: Water Res. Technol.

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ABSTRACT:The marketing and implementation of commercially available pulsedelectromagnetic field (PEMF) devices to ostensibly control scaling, in processes such as reverse osmosis (RO) and cooling-tower installations, is based on the notion that such devices enhance the coagulation of inorganic particles such as calcium carbonate. In order to provide a scientific basis for such claims, the precipitation characteristics of calcium carbonate under the influence of the PEMFs from two commercially available devices has been investigated under controlled conditions. Thus the rate and profile of calcium carbonate precipitation in the presence and absence of PEMF exposure of parent calcium nitrate and sodium carbonate aqueous solutions was tracked in parallel by UV absorption at 350 nm and by turbidity measurements. The morphology of the corresponding crystalline precipitates was, at the same time, also assessed using SEM. From these studies, is apparent that exposure of the parent solutions to the PEMF from one of these devices in particular can influence both the profile of CaCO3 precipitation and the morphology of the resulting microcrystals.

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The influence of the magnetic field on the crystallisation form of calcium carbonate and the testing of a magnetic water-treatment device

Cited by 94 publications

References 10 publications

Effects of magnetic field on the crystallization of CaCO3 using permanent magnets

Effects of magnetic field on the crystallization of CaCO3 using permanent magnets

Removal of Microcystis aeruginosa using nano-Fe3O4 particles as a coagulant aid

The influence of electromagnetic fields from two commercially available water-treatment devices on calcium carbonate precipitation

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