Application Of Magnetic Separation Research Articles

Fundamental Study on Recovery of Spilled Oil by Magnetic Pickering Emulsification

Heavy oil spills from stranded oil tankers are a global problem. The recovery of spilled oil must have a low environmental impact and must be capable of processing large quantities at high speeds. In this study, we investigated the application of magnetic separation for the recovery of spilled oil. Pickering emulsions were formed by heavy oil and magnetite, and recovery was carried out using a drum‐type permanent magnet. Pickering emulsions were successfully formed by stirring heavy oil A and magnetite, and magnetic separation experiments showed that up to 90% of the heavy oil A could be recovered. To recycle magnetite, a small amount of heavy oil was added to the recovered Pickering emulsions, and then a strong magnetic field of a superconducting bulk magnet was applied, which resulted in easy solid–liquid separation. The possibility of recycling magnetite after separation was also demonstrated. Finally, a small‐scale system using drum‐type permanent magnets was developed, and magnetic separation experiments were performed. The results showed that approximately 77% of the heavy oil A could be recovered. Particle trajectory simulations also demonstrated the recoverability of heavy oil at the sea surface. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Enhancing magnetism and magnetic separation of ultrafine chalcopyrite from talc through surface oxidation treatment

Magnetic separation has been proposed to greenly separate chalcopyrite and talc several decades ago, due to their extremely similar floatability of minerals. However, this approach was not achieved initially due to the inadequately magnetic induction of traditional magnetic separation, and fine particle size of chalcopyrite. Currently, the development of highly magnetic induction technology provides strong feasibility for this separation. In this work, we employed pulsating high-gradient magnetic separation (PHGMS) with highly magnetic induction (1.8T) to separate chalcopyrite and talc, and found that the PHGMS achieves a good separation of chalcopyrite from talc. But the chalcopyrite recovery decreased with the decrease of its particle size, and thus surface oxidation treatment was attempted to increase the magnetism and magnetic capture of ultrafine chalcopyrite. As a result, an increment of approximately 10 % was observed in the recovery of ultrafine chalcopyrite post-oxidation. As verified by the superconducting quantum interference device measurements, the oxidized ultrafine chalcopyrite exhibited a significant increase in the saturation magnetisation intensity, remanent magnetisation and coercivity values. Such magnetism enhancement is a result of the formation of paramagnetic Fe(III)–O–OH structures on the oxidized chalcopyrite surface, in terms of X-ray photoelectron spectroscopy and Mössbauer spectroscopy investigations. Furthermore, the density functional theory revealed that the formation of Fe(III)–O–OH structures caused a substantial increase in the magnetic moments of iron ions in antiferromagnetic chalcopyrite. These findings may extend the application of magnetic separation, and facilitate the flotation of ultrafine chalcopyrite from other minerals, at significantly reduced reagents use, and productive and environmental costs.

Sonochemical synthesis of Ag doped zinc sulfide /iron oxide nanocomposites for photocatalytic and magnetic separation applications

The influx of numerous organic contaminants and heavy metals into freshwater sources has serious effects on the aquatic environment and has made life very difficult. Synthesized photocatalysts have demonstrated considerable promise in the degradation of organic pollutants, such as dyes from various sources. This research presents the sonochemical synthesis of Ag doped zinc sulfide/iron oxide nanocomposites as magnetically separable photocatalysts with bifunctional applications. To determine the effect of the weight percentage of dopant on photocatalytic activity, Ag doped zinc sulfide/iron oxide nanocomposites were prepared at different concentrations of dopant, including 2.5, 5, and 10 wt%. Zinc sulfide/iron oxide nanocomposites with and without Ag dopant were employed as photocatalysts for degrading rhodamine B (RhB) as a color pollutant under visible and UV light. In the present study, the photocatalysts were characterized by using x-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), (energy dispersive x-ray spectroscopy (EDS), Brunauer-Emmet-Teller (BET), vibrating sample magnetometer (VSM), fourier transform infrared spectra (FTIR), photoluminescence (PL) spectrophotometry and ultraviolet–visible (UV–Vis) spectrophotometer to survey their structural, morphological, magnetic and optical features. Besides, the Mott-Schottky analysis was utilized to derive the carrier concentrations (ND), flat band potentials of the samples. The results show that doping of Ag in the zinc sulfide/iron oxide nanocomposite led to extended visible light absorption. In addition, approximately 96% of RhB was degraded by 5 wt% Ag doped zinc sulfide/iron oxide nanocomposite after 4hr of visible light irradiation. Moreover, 10 wt% Ag doped zinc sulfide/iron oxide nanocomposite demonstrated a considerable specific surface area (147.7 m2 g−1), which indicates a noteworthy adsorption capacity of 2.74 m g−1. Also, it was demonstrated that the zinc sulfide/iron oxide photocatalyst exhibited a strong magnetic capacity which was revealed by a saturation magnetization (Ms) of 58.22 emu/g, a remanent magnetization (Mr) of 1.4emu/g and a coercivity (Hc) of 11.62 Oe. Eventually, the photocatalytic mechanism of Ag doped zinc sulfide/iron oxide was thoroughly discussed. Therefore, to benefit from the potential of Ag dopants in the preparation of nanocomposites for wastewater treatment while maximizing the photocatalytic efficiency, a thorough study of their effect on the structural and optical properties of photocatalysts is required.

Magnetic Nanoseparation Technology for Efficient Control of Microorganisms and Toxins in Foods: A Review.

Outbreaks of foodborne diseases mediated by food microorganisms and toxins remain one of the leading causes of disease and death worldwide. It not only poses a serious threat to human health and safety but also imposes a huge burden on health care and socioeconomics. Traditional methods for the removal and detection of pathogenic bacteria and toxins in various samples such as food and drinking water have certain limitations, requiring a rapid and sensitive strategy for the enrichment and separation of target analytes. Magnetic nanoparticles (MNPs) exhibit excellent performance in this field due to their fascinating properties. The strategy of combining biorecognition elements with MNPs can be used for fast and efficient enrichment and isolation of pathogens. In this review, we describe new trends and practical applications of magnetic nanoseparation technology in the detection of foodborne microorganisms and toxins. We mainly summarize the biochemical modification and functionalization methods of commonly used magnetic nanomaterial carriers and discuss the application of magnetic separation combined with other instrumental analysis techniques. Combined with various detection techniques, it will increase the efficiency of detection and identification of microorganisms and toxins in rapid assays.

Reusable poly(2-acrylamido-2-methylpropanesulfonic acid)-grafted magnetic nanoparticles as anionic nano-adsorbents for antibody and antigen

Magnetite nanoparticles (MNPs) grafted with poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) and their use as anionic nano-adsorbents for positively charged antibody were herein presented. PAMPS grafted on MNP surface provided good water dispersibility and high negatively charged surface for electrostatic adsorption with positively charged entities, and MNPs provided a good magnetic responsiveness to facilitate the separation process. From transmission electron microscopy results, the size of the nanoclusters ranged between 50 and 200 nm in diameter with ca. 50–150 particles/cluster. Degree of the negative charge of PAMPS-grafted MNPs increased when increasing pH of the dispersion, indicating the pH-responsive properties of the MNPs. These MNPs were successfully used as nano-adsorbents for adsorption with anti-rabbit IgG through ionic interaction between negative charge of PAMPS-grafted MNP and positive charge of the antibody. In addition, the MNPs also provided the reusable ability by adsorption-desorption cycling process with higher than 80% adsorption ability after five consecutive reusing cycles. These hybrid materials should be alternative nano-adsorbents for other positively charged entities with high adsorption efficiency and reusable supports in magnetic separation applications.

Investigations of Metal Pollution in Road Dust of Steel Industrial Area and Application of Magnetic Separation

Pollution characteristics and ecological risks for metals in non-magnetic and magnetic road dust from steel industrial areas were investigated by applying a magnetic separation method. Metal (except for Al, Li, Ti, As, and Sb) concentrations in the magnetic road dust were 1.2 (Sn) to 7.8 (Fe) times higher than those in the non-magnetic road dust. For the magnetic road dust, the geo-accumulation index revealed a strongly to extremely polluted status for Cr, Zn, Cd, and Sb, a strongly polluted status for Mn, Cu, and Pb, and a moderately to strongly polluted status for Fe, Ni, Mo, and Hg. This result indicates that the dominant metal pollution sources of road dust in industrial areas were the traffic activities of heavy-duty vehicles. The mean content of magnetic particles accounted for 44.7% of the total road dust. The metal loadings in the magnetic road dust were 86% (Fe), 77% (Cr), 67% (Mn), 86% (Ni), 76% (Cu), 72% (Zn), 64% (Mo), and 62% (Cd), respectively. Removal of the magnetic fraction from road dust using magnetic separation techniques not only reduces metal contamination but can also improve effective road cleaning strategies or reduce waste generation.

Factors affecting bioleaching in the processing of non-metallics

Biotechnological treatment of non-metallics is based on bacterial leaching of raw material and dissolution of Fe. Bacterial iron dissolution ability is dependent on various physicochemical factors as temperature, acidity of solutions, redox potential, rapidity of water circulation and presence of organic sources. The Fe content in the quartz sands and feldspar samples by the biological leaching decreased as much as 60% and by subsequent using of electromagnetic separation of feldspars, the decrease of Fe content in 74% was achieved. However, the application of magnetic separation of quartz sands after bioleaching resulted in total iron removal of 93% and in such combined way prepared product contained 0.024 % of Fe2O3. Achieved results on iron removal point to the fact that combination of leaching and magnetic separation enables to obtain product usable in glass and ceramic industry.

Application of magnetic separation and reverse anionic flotation to concentrate fine particles of iron ore with high sulfur content

Application of magnetic separation and reverse anionic flotation to concentrate fine particles of iron ore with high sulfur content

Application of magnetic separation for oil spill remediation and recovery in Kuwait sea water

Application of magnetic separation for oil spill remediation and recovery in Kuwait sea water

Monolayer grafting of APTES modified graphene oxide on silica coated magnetite: Synthesis, characterization and application in heavy oil removal

Petroleum industries have been creating negative environmental and ecological impacts due to the formation of oilfield produced water (OPW) during refining processes. Graphene oxide (GO) as a chemical demulsifier was found non-recyclable; hence, it could cause environmental pollution. Thus, magnetic graphene oxide (M-GO) was proposed to prevent any possible contamination. In this work, GO, and M-GO were successfully synthesized and the produced M-GO composites were found coated with silica-coated magnetite (Fe3O4@SiO2) nanoparticles. As such, they possess excellent superparamagnetic properties. The demulsification tests demonstrated that 0.25 wt% of M-GO aqueous suspension achieved 98.53% of demulsification efficiency on the as-prepared crude oil-in-water emulsion, which was more superior than GO as the suspending oil floccules attached to M-GO can be separated effectively using magnetic separation. The optimizations of the demulsification process were conducted, and significant findings were included as the major novelty of this work. The recycling tests have proven that M-GO can be reused to perform demulsification effectively for ten times. Despite being able to reduce the demulsification costs in the industry, this research suggests that the excellent properties of M-GO can minimize the risk of polluting the environment due to leakage of demulsifier through the application of magnetic separation.

Mechanism of Calcium Sulphate on the Aggregation and Growth of Ferronickel Particles in the Self-Reduction of Saprolitic Nickel Laterite Ore

Saprolitic nickel laterite is characterized by relatively low iron and nickel contents. Iron and nickel oxides are reduced to form fine ferronickel particles that disperse and embed in silicates in the reduction process, limiting the application of magnetic separation to extract ferronickel. Additives are applied to promote the aggregation and growth of ferronickel particles, then the large ferronickel particles will be separated by fine grinding and recovered via magnetic separation. Calcium sulphate is considered to be capable of increasing the size of ferronickel particles considerably. Due to the decomposition of calcium sulphate in the reduction process, the mechanism of calcium sulphate on the aggregation and growth of ferronickel particles should be conducted studied in-depth. The current work explores the effects of calcium sulphate, elemental sulphur, and calcium oxide on the formation of ferronickel particles in a saprolitic nickel laterite ore. The results showed that the formation of an Fe-FeS eutectic and the mineral structure transformation contributed by calcium oxide were all conducive to the mass transfer of ferronickel particles in gangue, ferronickel particles aggregated and grew up at the boundary between the hole and the gangue. The self-reduction, fine grinding, and magnetic separation of nickel laterite ore in the presence of three types of additive were examined. Nickel laterite ore with 7.88 wt% coal, 12 wt% calcium sulphate reduced at 1200 °C for 30 min, a ferronickel concentrate of Ni 8.08 wt%, and Fe 79.98 wt% was obtained at a nickel and iron recovery of 92.6% and 79.9%, respectively.

Preparation and Application of Iron Oxide Nanoclusters

Magnetic iron oxide nanoclusters, which refers to a group of individual nanoparticles, have recently attracted much attention because of their distinctive behaviors compared to individual nanoparticles. In this review, we discuss preparation methods for creating iron oxide nanoclusters, focusing on synthetic procedures, formation mechanisms, and the quality of the products. Then, we discuss the emerging applications for iron oxide nanoclusters in various fields, covering traditional and novel applications in magnetic separation, bioimaging, drug delivery, and magnetically responsive photonic crystals.

Magnetic separation applications in the final treatment of sluice box concentrates

Magnetic separation applications in the final treatment of sluice box concentrates

Industry applications of magnetic separation based on nanoparticles: A review

Industry applications of magnetic separation based on nanoparticles: A review

Shaping iron oxide nanocrystals for magnetic separation applications.

Iron oxide nanostructures are attractive for a variety of bio-related applications given their wide range of magnetic properties. Here, we report on the study of the magnetophoretic mobility of octapod-shaped nanocrystals, which we relate to stoichiometry, quality and elongation in the 111 direction of these cubic structures. This special morphology combines magnetocrystalline anisotropies, increases shape anisotropy and hinders the formation of an epitaxial wüstite-magnetite interface. As a result, one obtains nanocrystals with large magnetic susceptibility and small coercivity, that is, with optimum characteristics for magnetic guidance, separation, and drug delivery, due to the increased magnetophoretic mobility displayed.

Reusable magnetic nanocluster coated with poly(acrylic acid) and its adsorption with an antibody and an antigen

ABSTRACTThe synthesis of negatively charged magnetite nanoclusters grafted with poly(acrylic acid) (PAA) and their application as reusable nanosupports for adsorption with antibodies and antigens are presented in this article. They were facilely prepared via the free‐radical polymerization of PAA in the presence of functionalized magnetite nanoparticles to obtain highly negative charged nanoclusters with a high magnetic responsiveness and good dispersibility and stability in water. According to transmission electron microscopy, the sizes of the nanoclusters ranged between 200 and 500 nm, without large aggregation visually observed in water. The hydrodynamic size of the nanocluster consistently increased with increasing pH of the dispersion; this indicated its pH‐responsive properties, which was due to the repulsion of the anionic carboxylate groups in the structure. This nanocluster was successfully used as an efficient and reusable support for adsorption with anti–horseradish peroxidase antibody. It preserved higher than a 97% adsorption ability of the antibody after eight reuse cycles; this signified the potential of this novel nanocluster as a reusable support in the magnetic separation applications of other bioentities. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46160.

Micaceous iron oxide production by application of magnetic separation

Micaceous iron oxide production by application of magnetic separation

Application of magnetic separation for modifying the composition of basalt raw materials

The results of studying the process of modifying the composition of basalt raw materials using the magnetic separation method are reported based on the example of basalt of the Myangdukha deposit (Arkhangelsk oblast). The chemical and phase compositions of magnetically enriched and magnetically depleted fractions have been determined by mass spectrometry and X-ray powder diffraction. The process of sintering these fractions has been studied by the DSC/TG method. The phase composition of sintering products has been studied and some of the physicochemical properties of the obtained samples have been determined.

Magnetically recyclable Bi/Fe-based hierarchical nanostructures via self-assembly for environmental decontamination.

Pristine bismuth ferrite usually possesses weak magnetic properties (e.g., saturation magnetization Ms < 3 emu g(-1)) for practical magnetic separation applications. Herein, a superparamagnetic bismuth ferrite with coral-like hierarchical morphology (BFO-M) was fabricated through methanol solvothermal treatment of the as-prepared Bi2Fe4O9 nanoclusters (P-BFO). The BFO-M shows a higher Ms of ∼31 emu g(-1) compared to that of P-BFO treated in water (BFO-A), in ethanol (BFO-E) and in ethylene glycol (BFO-G). Compared to single-crystalline Bi2Fe4O9 (PS) and Bi2Fe4O9 clusters (NSP), BFO-M shows an excellent organic pollutant removal rate by virtue of its high adsorption capacity and catalytic activity when methyl orange (MO) is used as the model organic pollutant. BFO-M also exhibits good visible light photo-Fenton oxidation rates for pharmaceuticals and pesticides. Even at a low catalyst loading of 0.12 g L(-1), the removal rate of organic pollutants (e.g., 5-fluorouracil, isoproturon) can be ∼99% in 100 min under visible light irradiation. Besides, BFO-M is also a good adsorbent for different kinds of heavy metal ions (Pb(ii), Cr(iii), Cu(ii), As(v), etc.). For example, its maximal adsorption capacity for Pb(ii) is 214.5 mg g(-1). The used BFO-M can be recovered via magnetic separation. The outstanding performances of BFO-M can be ascribed to its coral-like hierarchical morphology which consists of the self-assembly of 1D nanowires (∼6 nm in diameter) and 2D ultrathin nanoflakes (∼4.5 nm in thickness). A schematic illustration of its morphology formation is proposed.

Assembly of Maghemite Nanoparticles Into Particulate Nanosheets and Their Application in Wastewater Treatment.

The maghemite particulate nanosheets (MPNs) are prepared in solvothermal system by connecting the nanoparticles in two-dimension. The interconnected MPNs sustain a mesopores structure with a high accessible surface area of 164 m2/g, and have a high performance for Cr6+ adsorption. The Cr6+ removal process fit with Langmuir adsorption model with an adsorption capacity of 20.41 mg/g. The purified solution could reach a residual concentration of 0.002 mg/L for MPNs, which is much less than the concentration in the solution of 0.249 mg/L when the nanoparticles are used. The synthesized MPNs with a saturation magnetization of 70.51 emu/g at room temperature can be easily collected and separated by an external magnet in liquid. Exchange coupling and shape anisotropy are the main reason for the higher Ms of MPNs. The unique structure with large surface area and high saturation magnetization make the MPNs favourable for the application of magnetic separation.