Efficient Magnetic Adsorbent Research Articles

Coconut shell based activated carbon–iron oxide magnetic nanocomposite for fast and efficient removal of oil spills

An efficient magnetic adsorbent nanocomposite material is prepared by simple chemical methods using coconut shell based activated carbon and iron oxide nanoparticles. The composite material shows good oil retention capacity with fast kinetics and can be recovered along with the adsorbed oil by using an external magnet. The adsorbent material can be reused after recovering either by heat treatment or by solvent extraction. Hence, the magnetic nanocomposite is shown to be an efficient and recyclable potential candidate for removal of oil spills by magnetic separation.

Synthesis, Characterization, and Adsorptive Properties of Magnetic Cellulose Nanocomposites for Arsenic Removal

In this study, the magnetic cellulose nanomaterials, containing magnetic nanoscale zerovalent iron (nZVI) and cellulose, were prepared by a novel reduction method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The XRD and XPS results demonstrated the formation of zerovalent iron nanoparticles in the nanocomposite materials. With a saturation magnetization of 57.2 emu g−1, the cellulose@nZVI composites could be easily separated from solutions in 30 s through the external magnetic field. We investigated the adsorption performance of the magnetic cellulose nanomaterials for As(III) removal from aqueous solutions. The experimental results showed that arsenite adsorption followed the pseudo-second-order kinetic model and Langmuir isotherm model. A maximum removal of 99.27 % was observed for an initial concentration 10 mg L−1, at pH 8.0, and an adsorbent dose of 1.0 g L−1. Considering the high adsorption capacity, fast adsorption rate, and quick magnetic separation from treated water, the cellulose@nZVI composites were expected to be an efficient magnetic adsorbent for arsenic removal from aqueous solutions.

Sea-urchin-like iron oxide nanostructures for water treatment

To obtain adsorbents with high capacities for removing heavy metals and organic pollutants capable of quick magnetic separation, we fabricated unique sea-urchin-like magnetic iron oxide (mixed γ-Fe2O3/Fe3O4 phase) nanostructures (called u-MFN) with large surface areas (94.1m2g−1) and strong magnetic properties (57.9emug−1) using a simple growth process and investigated their potential applications in water treatment. The u-MFN had excellent removal capabilities for the heavy metals As(V) (39.6mgg−1) and Cr(VI) (35.0mgg−1) and the organic pollutant Congo red (109.2mgg−1). The u-MFN also displays excellent adsorption of Congo red after recycling. Because of its high adsorption capacity, fast adsorption rate, and quick magnetic separation from treated water, the u-MFN developed in the present study is expected to be an efficient magnetic adsorbent for heavy metals and organic pollutants in aqueous solutions.

MnFe2O4/chitosan nanocomposites as a recyclable adsorbent for the removal of hexavalent chromium

Magnetic MnFe2O4/chitosan nanocomposites (MCNCs) were prepared by a simple method. The as-prepared sample was characterized by various technologies. Results indicated that the MnFe2O4 nanoparticles were coated by chitosan without phase change, and the as-prepared MCNCs displayed superparamagnetic properties with a high saturation magnetization (39.5emug−1). The as-prepared MCNCs were used to remove Cr(VI) from low concentration solutions (0.6–1.0mgL−1). And it was found that the MCNCs showed a high Cr(VI) removal capacity of 35.2mgg−1. The effects of various parameters, such as pH, temperature, agitation time, and initial concentration on the adsorption performance were investigated. The experimental data were well described by the pseudo-second-order kinetics and Freundlich isotherm model. Taking advantages of the high adsorption capacity and quick magnetic separation from treated water, the MCNCs can be regarded as an efficient magnetic adsorbent for Cr(VI) removal from aqueous solution.

Preparation of multiferroic Co substituted BiFeO3 with enhanced coercive force and its application in sorption removal of dye molecules from aqueous solution

Multiferroic Co substituted BiFeO3 (BiFe0.95Co0.05O3) compound was synthesized by complex sol–gel method and its potential application as an efficient magnetic adsorbent in sorption removal of organic contaminants (like Rhodamine B as a model compound) was investigated. The XRD, Raman, and PPMS measurement revealed that Co substituted BiFeO3 enhances magnetic properties dramatically at room temperature without inducing any impurity phase. This aspect is very useful for many applications of Co substituted BiFeO3 especially in magnetic separation of this catalyst after its utilization in water purification. The adsorption kinetics, isotherm, thermodynamic as well as the possible sorption mechanism was studied through batch experiments. Almost no negative effect on the sorption performance (i.e. the sorption rate and saturated sorption capacity) was found after substitution of Co in BiFeO3. In addition, this substitution give rise to much higher coercive force of BiFe0.95Co0.05O3 which can be recycled more easily by magnetic separation technology.

Magnetic Iron Oxide Chestnutlike Hierarchical Nanostructures: Preparation and Their Excellent Arsenic Removal Capabilities

To obtain adsorbents with high As(V) removal capacity and quick magnetic separation simultaneously, we have fabricated maghemite (γ-Fe(2)O(3)) and magnetite (Fe(3)O(4)) chestnutlike hierarchical nanostructures (CHNs) with strong ferromagnetic property by annealing the Fe(2)O(3) chestnutlike amorphous core/γ-phase shell hierarchical nanoarchitectures (CAHNs) at different temperatures in a nitrogen atmosphere. Compared to the Fe(2)O(3) CAHNs, the saturated magnetization of the as-obtained γ-Fe(2)O(3) CHNs is enhanced over 10 times, while the As(V) removal capacity is maintained 74% and reaches 101.4 mg·g(-1). Both of the as-obtained γ-Fe(2)O(3) and Fe(3)O(4) CHNs can be separated simply and rapidly from treated water by magnetic separation after As(V) adsorption treatment. The As(V) adsorption process of the as-obtained γ-Fe(2)O(3) CHNs obeys well the Freundlich isotherm model rather than the Langmuir one, suggesting that a multilayered adsorption occurs on the surface of the γ-Fe(2)O(3) CHNs. Taking advantages of the high adsorption capacity, fast adsorption rate and quick magnetic separation from treated water, the γ-Fe(2)O(3) CHNs developed in the present study is expected to be an efficient magnetic adsorbent for As(V) removal from aqueous solutions.