Determining the Magnetic Susceptibility of Ferroparticles from the Susceptibility of Their Dispersive Samples

Polismakova

et al. 2022

AMM

There is a lack of information on the magnetic properties of particles of such materials as powder magnetic (modified by inclusions of magnetite and maghemite) carbon sorbents intended for water purification from various kinds of impurities and, what is especially important, allowing to perform the prompt isolation of the spent sorbent – by magnetic separation. The data on the magnetic susceptibility χ of the particles of these sorbents, found by the developed experimental calculation method based on the concept of the corresponding magnetometry of a moderately rarefied dispersed sample with a dispersed phase of the particles under study, are presented. Experimental dependences of the magnetic susceptibility of <χ>of a dispersed sample on the volume fraction γ of controlled particles in it have been obtained - for different values of the magnetic field strength H in the range from 22 to 61 kA/m, i.e. in the postextremal region for the susceptibility. In addition to the necessary assessment of their linear, located at γ ≤ 0.15-0.2, sections, this also made it possible to find and phenomenologically describe the field dependences of the generalized data of the reduced susceptibility of <χ>/γ, i.e. data χ: in the form of an inverse power function with a power of 0.7 ... 0.8 at H.

Section: The Original Concept Of An Approach To Determining the Magne...mentioning

confidence: 94%

Magnetic Susceptibility of Powders and Magnetic Particles (Modified Inclusions of Iron Oxides) Carbon Sorbents

Polismakova

et al. 2022

AMM

“…Previous studies suggested that the magnetic susceptibility of the dispersive media linearly depends on the particle concentration for relatively small volume fractions (~<0.2) (Sandulyak et al 2019;Sandulyak et al 2017). According to these studies, at this concentration the distance between the nanoparticles are sufficiently long to prohibit mutual magnetic effect.…”

Section: Numerical Modellingmentioning

confidence: 98%

Magnetofluidic spreading in circular chambers under a uniform magnetic field

Maleki

Zhang

Kashaninejad

et al. 2020

Microfluid Nanofluid

Elucidating the microscale interaction between magnetism and fluid flow is of great importance for designing micro-magnetofluidic gradient generators, micromixers, and particle sorters. Coflowing magnetic and non-magnetic fluids can lead to instability at their interface and subsequent rapid mixing. The mismatch in the magnetisation of the fluids leads to instabilities. The present study systematically investigates the magnetofluidic spreading phenomena of both magnetic nanoparticles and non-magnetic fluorescent dye in consecutive circular chambers. Numerical simulations and experimental investigations were conducted to thoroughly evaluate the physics of magnetofluidic spreading. We show that the presence of the consecutive chambers can enhance magnetofluidic spreading by slowing down the flow and increasing the mass transfer rate transversal to the flow direction. The numerical results reveal that the magnetic force, induced by the magnetic susceptibility gradient, generates cross-sectional secondary flows that steer particles toward both the top and bottom walls. The induced secondary flow also enhances the transport of fluorescent dye, thereby leading to a higher mass transfer rate as compared to pure molecular 2 diffusion. The findings provide further insights into the microscale spreading phenomenon of magnetic and non-magnetic particles in a magnetic field.

“…While it is different for different environments, it is known to vary significantly also for the same environment: depending on its temperature. Of course, this is reflected in the results of magnetophoresis, as evidenced by a number of direct data [9,[13][14][15][16][17]. In the same cases, when information about this factor (thermo-viscosity) is not provided or it is insufficiently complete, there may even be an opinion about the "inconsistency" of the results (at first glance, under the conditions of obtaining them, as it were).…”

Section: The Relevance Of Assessing the Role Of Viscosity And Density...mentioning

confidence: 99%

“…If we have analytical (phenomenological) temperature dependences of the viscosity η of liquid (liquid-dispersed) media [1,13,17], then one or another of them can be used in (1) to clearly reflect the role of the parameter t in the corresponding expressions for the efficiency ψ magnetic release and limiting regime speed [υf], where the parameter t does not appear explicitly.…”

Section: The Role Of Temperature Phenomenological Temperature Depende...mentioning

confidence: 99%

“…As for obtaining analytical expressions that would allow one to approximate the existing temperature dependences of the viscosity η of a particular medium (Fig. 1, a, b), for this it is advisable to use a fairly practical approach [1,13,17], depicting one or another dependence η on t, for example, in semi-logarithmic coordinates. So, if in the most interesting temperature range t (for performing a certain version of magnetophoresis), the considered dependence of η on t, being depicted in one of two types of such coordinates, is quasi-linearized, then this indicates its correspondence to the logarithmic or exponential functions.…”

Section: The Role Of Temperature Phenomenological Temperature Depende...mentioning

confidence: 99%

See 1 more Smart Citation

On the Influence of Viscosity and Density of a Liquid Medium on Efficiency of Magnetophoresis. Role of Temperature

IOP Conf. Ser.: Earth Environ. Sci.

Ershova

et al. 2022

Significant, but usually insufficiently disclosed and analyzed, parameters of magnetophoresis of magnetoactive particles of liquid-dispersed media are the dynamic viscosity and density of the medium, as well as its temperature, which usually significantly affects the viscosity. The role of viscosity and density is analyzed using the example of such a variant of magnetophoresis as filtration magnetic separation (FMS). This role is reflected in the basic expressions for filtration efficiency and rate limiting. To legalize the role of temperature in these expressions, an approach was used to obtain phenomenological temperature dependences of the viscosity of a number of liquid media by identifying these dependences (or their characteristic sections), amenable to quasi-linearization in semi-logarithmic coordinates. Thus, the possibility of their description by functions of the logarithmic and exponential form is shown, and therefore - an alternative representation of expressions for the efficiency and limiting speed of FMS.