Sorption Capacity For Ions Research Articles

Perspective ecological processes of agricultural sewage water treatment when using non-traditional sorbents

The usage of natural sorbents in sewage water treatment technologies, in particular agro-industrial complex, has a number of environmental and economic advantages. Non-traditional sorbents, which are concentrated in many parts of Ukraine, are cheap raw materials for sewage water treatment. The sorption properties of the upland and lowland peat species of the Gamaliivka-Grybovychi deposit, which were studied early, indicate their high sorption capacity for ammonium ions, which, if they enter water bodies, cause a number of environmental problems. According to the results of the ecological assessment of sewage water of meat processing facility, the chicken processing facility and milk processing plant, it was found out the exceedance of the acceptable limits for the content of ammoniacal nitrogen, respectively: 1.3–3 MPC; 3.8 MPC and 2.5 MPC. This component is a water pollutant and a “crop” of yield in agriculture, since nitrogen is an important element of plant nutrition. The rational usage of natural resources involves the complex usage of natural resources. The nitrogen absorbed by ammonium peat, as well as the peat itself is a sufficient fertilizing land, so the use of used peat complex in agriculture allows to solve not only problems of fertilizers, but also to achieve greening in sewage water treatment technologies. Greening as a whole is a result of waste minimization, and today there are two main areas: new technological non-waste technology together with low-waste technology and waste regeneration. This paper presents a comparison of the physiological indices of plants, depending on the application of the species and form of Gamaliivka-Grybovychi peat deposit, Yavoriv district, when fertilizing the substrate (sand as a background) of the study areas. The influence on the quality of ascent and growth of vegetative culture – watercress, natural form of the top and lowland peat species, as well as their waste forms obtained as a result of the process of purification of ammonium ions, modeling the sewage water of the agro-industrial complex, was investigated. The mass of the harvest from the experimental fields was determined and compared. The differences of lowland and upland peat species are due to its origin, which significantly affects their chemical composition. The plants fuelled with peat are much higher in the mass than those crops that were grown with adding of peat substrate into the lowland. However, the used form of lowland peat provided a 1.57 times higher harvested crop yield than the used upland sample of the studied sorbent.

Non-covalent self-assembly of multi-target polystyrene composite adsorbent with highly efficient Cu(II) ion removal capability

Functionalized nanocomposite adsorbents based on multiple sites of sorption are critically important for advancing removal of heavy metal ions. Herein, a non-covalently assembly strategy for fabrication of efficient adsorbent with multiple-site adsorption capability is introduced. A novel hybrid nanomaterial was fabricated by encapsulating chitosan molecules (CS) into charged polystyrene resin (PS) through electrostatic adsorption. The resulting hybrid absorbent (PS-CS) demonstrates highly efficient sorption toward cupric ion, mainly because of the electrostatic interactions of sulfonate group and chelation of NH2 and OH groups of chitosan with cupric ion. Meanwhile, the obtained composites with interior well-dispersed chitosan molecules give specific selectivity for cupric ion in the present of divalent competition ions such as Ca2+ and Mg2+. Adsorption equilibrium data can be described with Freundlich isotherms model and the pseudo-second-order model. The kinetic rate constants have been determined for PS and PS-CS nanocomposite. In this paper, it is suggested that charged groups in host materials not only enhance the fixation and dispersion performance of embedded molecules but provide more target sites for nanocomposite, thus enhancing capacity for sorption of metal ions. Therefore, construction of multi-target nanocomposites provides conceivably promoted development of highly efficient adsorbents for toxic metals abatement.

Implementation of Carboxymethyl cellulose/Acrylic acid/ Titanium dioxide Nanocomposite Hydrogel in Remediation of Cd(II), Zn(II) and Pb(II) for Water treatment application

In this study Acrylic acid/ Carboxymethylcellulose/Titanium dioxide (AAc/CMC-TiO2) hydrogel nanocomposite was synthesized by free-radical crosslinking copolymerization via gamma radiation. It was characterized using FT-IR and swelling properties. The swelling percentage increases with increasing time until reaches a certain limiting value after 6h The synthesized nanocomposite was used as an adsorbent for remediation of Cd(II), Zn(II) and Pb(II) from aqueous solutions by the static adsorption technique. It was found that the optimum pH for the adsorption is 5 and the sorption process is carried out at a fast operating time, 30-40 min, for all investigated metal ions. It was also found that the metal ions sorption capacity decreases with increasing the dosage of AAc/CMC-TiO2 from 5 to 150 mg. A progressive increase in the metal ions sorption capacity was obtained with increasing the initial metal ion concentration from 0.01 to 0.05 mol L-1 and the saturation of the sorbent active sites was done at initial metal ions concentration at 0.1 mol L-1. No significant interference on the removal of Pb (II) in the presence of NaCl, Na-acetate, KCl, KNO3 and NH4Cl ions while a slight decrease in the removal of Cd (II)and Zn(II) was done. The pseudo-second-order kinetic model and Freundlich adsorption model describe well the kinetic and isotherm, respectively, of the adsorption process of the investigated ions.

Equilibrium, kinetic, and thermodynamic studies on the sorption of some heavy metal ions by the phosphorus-containing polymer sorbent

The sorption of Cu+2, Ni+2, Co+2, and Zn+2 ions onto the phosphorus-containing sorbent were studied as a function of the contact time, temperature, and concentration of the initial metal ions. The equilibrium studies are presented by the Langmuir, Freundlich, and Temkin isotherm models. The sorption data are well described by the Langmuir isotherm model, and they also can be simulated by the Freundlich isotherm model. The pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were applied to test the experimental data of the kinetic studies. The pseudo-second-order kinetic model provided the best correlation of the experimental data compared to the other kinetic models. The sorption capacity of the metal ions increased with temperature increasing. The positive value of enthalpy (ΔH°) and the negative value of Gibbs free energy (ΔG°) indicated that the sorption process was endothermic and spontaneous.

Development of chitosan-poly(ethyleneimine) based double network cryogels and their application as superadsorbents for phosphate

The fabrication of novel chemically cross-linked double network cryogels (DNC), with an abundant number of amine groups, based on chitosan (CS) cross-linked with glutaraldehyde (GA), as the first network, and poly(ethyleneimine) (PEI), with a concentration up to 15% cross-linked with ethyleneglycol diglycidyl ether (EGDGE), as the second network, and their enhanced sorption capacity for phosphate ions are presented here. The phosphate sorption was fast (equilibrium in three hours) and well modeled by the pseudo-second-order kinetic model. The experimental sorption isotherms were fitted with Langmuir, Freundlich, Sips and Dubinin-Radushkevich isotherm models. The Langmuir and Sips isotherms were the best in modeling the sorption process. The maximum sorption capacity given by the Langmuir isotherm for the DNC having the highest content of GA and the highest concentration of PEI was about 343 mg phosphate/g, which placed this novel sorbent among the best sorbents for phosphate recently reported in literature.

Improved Physico-chemical Properties of Mesoporous Carbon by Functionalization with Aminopropyl-polydimethylsiloxane (AP-PDMS)

The present research reports on the synthesis and properties of mesoporous carbon (MC) surface with functionalized aminopropyl-polydimethylsiloxane (AP-PDMS). The aim of MC surface modification was focused on the improvement of its electrical properties (EC electric conductivity), as well as its sorption capacity for cesium ions. In order to anchor AP-PDMS molecules, an intermediate functionalization step of the MC surface with carboxylic groups was carried out. In this respect, two different methods, namely: (i) sonication in the presence of the hydrogen peroxide (MC-COOH) and (ii) gas-plasma activation (MCA) have been considered for carbon surface oxidation. Further, AP-PDMS component was crosslinked to the COOH-reached carbon surface. Fourier transform infrared spectroscopy (FT-IR) and energy dispersion spectroscopy (EDX) were used to confirm the presence of AP-PDMS molecules on MC surface. Morphological and textural properties of the obtained composites have been investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption–desorption measurements, as well as their electrical properties (EC). The obtained results reveal the grafting of silane-containing component onto MC surface, an improved electrical conductivity of the synthesized composites toward MC sample. Also, the functionalization proved to be efficient in the sorption process of the cesium ions from aqueous solutions, despite the fact that the materials surface became hydrophobic.

The Influence of Synthesis Conditions on Hydroxyapatite Adsorption Characteristics in the Process of Zn(II) and Pb(II) Removal from Single and Binary Solutions

Two types of nanohydroxyapatite samples have been obtained by wet chemical precipitation synthesis, involving calcium nitrate tetrahydrate and diammonium hydrogen phosphate as precursors in different conditions. Powders obtained were characterized by X-ray diffraction (XRD) and FTIR spectroscopy. The equilibrium isotherm models related with lead and zinc ions removal from synthetic aqueous solutions have been also investigated. According to this research study, it has been found that the nanohydroxyapatite samples show good heavy metals adsorption capacity, and selectivity for lead ions. It was also observed a slow decreasing of sorption capacity of heavy metal ions from binary solutions compared to that registered from single heavy metal ion solutions.

Synthesis of Chitosan@activated Carbon Beads with Abundant Amino Groups for Capture of Cu(II) and Cd(II) from Aqueous Solutions

In this study, chitosan and bio-based activated carbon obtained from sugarcane bagasse biowaste were used for the synthesis of efficient sorbent for Cu(II) and Cd(II) ion via precipitation method. The prepared material was enriched with amino groups through grafting tetraethylenepentamine and tested for heavy metal remediation from water samples. The influence of pH was investigated showing optimum sorption at pH 6 for Cu(II) and Cd(II). Sorption tests, explained by means of the most common sorption models, evidenced that the best performances were reached pointing out the promising application of the prepared sorbent for water purification treatments: Uptake kinetics are relatively fast: the equilibrium was reached within 140 min; and the kinetic profiles were preferentially fitted by the pseudo-second order rate equation. Sorption isotherms are fitted by Langmuir equation. The sorbent showed high metal ion sorption capacity with negligible influence of ion strength. The maximum sorption capacities reached 3.44 and 2.38 mmol g− 1 for Cu(II) and Cd(II), respectively at 298 K. Thermodynamic parameters were evaluated through variation of temperature. The sorption is unfavorable at elevated temperatures. Metal ions were successfully desorbed using 1 M HNO3 solution.

Lead and cadmium removal from single and binary metal ion solution by novel hydroxyapatite/alginate/gelatin nanocomposites

Imperfect treatment of effluents from the industries contain moderate amounts of metallic cations will carry other issues to human health and environment. When toxic substances enter into water bodies, they get dissolved in water or get deposited on the bed. This results in the deterioration of water thereby affecting the aquatic ecosystems. In the area of environmental remediation, nanosized materials offer potential for efficient removal of pollutants and biological contaminants. In this present work, heavy metal ions (Pb2+ and Cd2+) sorption capacity of HA-alginate/gelatin nanocomposite has been investigated as a function of adsorbent dosage, adsorbate concentrations and contact time. The sorption kinetics exhibited the best fit to the pseudo-second order equation and the equilibrium followed Langmuir isotherm model. The equilibrium removal capacity of HA/Alg composite from Langmuir isotherm model was evaluated to be 550 and 361 mg/g for Pb2+ and Cd2+. The removal capacity of HA/Alg/Gel composite was evaluated to be 616 and 388 mg/g for Pb2+ and Cd2+. In the case of binary metal ion system, removal capacity of the adsorbent for a particular metal ion was hindered by the presence of another ion in the medium. The results of this study will be useful for further development of ceramic/polymer composites for environmental applications.

Removal of Copper (II) Ions in Aqueous Solutions by Sorption onto Alkali Activated Fly Ash

Fly ash is a particulate material produced from coal combustion power plants with major components are silica, alumina, iron oxide, calcium oxide, magnesium oxide, and carbon which are ideal for metal adsorbents. The potential use of fly ash in the wastewater treatment process is obvious because it can be obtained cheaply in large quatities and it can be used as an adsorbent. However, fly ash still shows lower adsorption capacity unless it is activated. In this study, fly ash activated by NaOH 14 M and KOH 14 M solutions. The batch experiments were carried out to study the sorption of copper ions from aqueous on alkali activated fly ash. The influence of initial concentration and contact time were examined at constant pH and dose of adsorbent. The sorption capacity of copper ions increased with the initial concentration and contact time. The sorption capacities followed the order Na1>Ka1>FA. The adsorption isotherm model exhibited that the Langmuir model is very suitable with copper ions adsorption onto fly ash and alkali activated fly ash. Kinetic study shows that adsorption of copper ions onto FA, Na1, and Ka1 follows the pseudo second-order kinetics.

Application of ion exchangers for the purification of galvanic wastewater from heavy metals

ABSTRACTThe aim of the present study was to investigate the sorption and physicochemical properties of the chelating ion exchangers with bis(2-pyridylmethyl)amine and aminophosphonic functional groups before and after the sorption of galvanic wastewaters. The study was carried out on the Dowex M4195, Lewatit® MonoPlus TP 220, Purolite S 940 and Purolite S 950 ion exchangers. For the practical use of the studied ion exchangers in the process of wastewater purification, the sorption capacity of the above-mentioned ions was determined depending on the phase contact time and sorption process in the whole volume of the beads.

Synthesis of Calcium-Deficient Carbonated Hydroxyapatite as Promising Sorbent for Removal of Lead Ions

This study is devoted to the synthesis of calcium-deficient carbonated hydroxyapatite and the modeling study of its sorption capacity for heavy metal ions on the example of Pb2+. Sorption of Pb2+ ions was investigated in physiological conditions. It was found that the synthesized calcium-deficient carbonated hydroxyapatite is nanosized and has an excellent sorption capacity for Pb2+ ions – up to 588 mg/g. Characterization of the solid particles after sorption by XRD and FTIR methods showed that in the sorption process, a new crystal phase of hydroxypyromorphite was formed. Also, the sharp decrease of pH in the initial period when the material is exposed to the heavy metal solution was explained. This effect is attributed to the fast formation of the surface complex =POPb+, followed by the dissociation of structural water molecules in the surface layer of the material under the influence of the adsorbed lead ions.

Efficient and selective removal of heavy metals using microporous layered silicate AMH-3 as sorbent

AMH-3 is a zeolite-like material with a three-dimensional uniform porous structure, layered structure, and abundant exchangeable cations. Herein, the use of AMH-3 to remove heavy metals present in aqueous solutions is investigated for the first time. Pristine AMH-3 and metal-sorbed AMH-3 were characterized with inductively coupled plasma atomic emission spectroscopy (ICP-AES), field emission scanning electron microscopy (FE-SEM), 29Si cross polarization magic angle spinning nuclear magnetic resonance spectroscopy (CP MAS NMR) and X-ray diffraction (XRD). The removal of heavy metals by AMH-3 was found to be governed by ion exchange rather than surface adsorption, and no significant change occurred in the structure of the AMH-3 during the ion exchange. The removal of various heavy metal ions (Pb2+, Cu2+, Cd2+, and Zn2+) onto AMH-3 from aqueous solutions was conducted using a batch method. The effects of influential parameters, such as the initial metal ion concentration and contact time, on the sorption process were studied. The metal ion sorption capacity and removal efficiency were mainly dependent on the difference between the effective pore size of the AMH-3 and the hydrated radius of the metal ion. The sorption isotherm data were well fitted by Langmuir (for Pb2+, Cu2+, and Zn2+) and Freundlich (for Cd2+) models. The sorption kinetics data were well fitted by a pseudo-secondorder kinetic model. Competitive sorption experiments revealed an order of metal ion affinity of Pb2+>Cu2+>Zn2+>Cd2+. These findings indicate that AMH-3 is suitable for the efficient and selective removal of heavy metals from aqueous solutions.

Highly Efficient Composite Polysulfone Beads Containing a Calix[4]arene–Monocrown-6 Ligand and a Room Temperature Ionic Liquid for Radiocesium Separations: Remediation of Environmental Samples

Composite polymeric beads (CPBs) containing bis(octyloxy)calix[4]arene–monocrown-6 (BOCMC), room temperature ionic liquid, and polysulfone were prepared by a phase inversion technique for the selective separation of radiocesium from aqueous feeds. The CPBs displayed excellent stability with respect to the leaching of BOCMC. Experimental sorption data indicated that maximum sorption of cesium occurred within the aqueous phase of pH 4–10. However, the sorption kinetics was slow, and about 2 h of equilibration was necessary for obtaining the equilibrium conditions. The sorption kinetics data could be best fitted in the pseudo-second-order kinetics rate equation and interparticle diffusion model. The metal-ion sorption onto the beads followed the Langmuir monolayer sorption phenomenon with a cesium ion sorption capacity of 1.56 ± 0.03 mg per 1 g of CPBs. The Langmuir chemisorption process was validated from the sorption energy obtained from the Dubinin–Radushkuvich and Temkin isotherm models. In a bid to appl...

Selective Molecularly Mediated Pseudocapacitive Separation of Ionic Species in Solution.

We report the development of a dual-electrode pseudocapacitive separation technology (PSST) to capture quantitatively, remotely, and in a reversible manner value-added carboxylate salts of environmental and industrial significance. The nanostructured pseudocapacitive cell exhibits elegant molecular selectivity toward ionic species: upon electrochemical oxidation, a poly(vinylferrocene) (PVF)-based anodic electrode shows high selectivity toward carboxylates based on their basicity and hydrophobicity. Simultaneously, on the other side of the electrochemical cell, a poly(anthraquinone) (PAQ)-based cathodic electrode undergoes electrochemical reduction and captures the counterions of these carboxylates. The separation and regeneration capability of the electrochemical cell was evaluated through the variations in concentration of the carboxylates in polar organic solvents (often used in electrocatalytic processes) upon electrochemical charging and neutralization of the polymeric cargo of the electrodes, respectively. The strong separation efficiency of the system was indicated by its ability to capture an individual carboxylate (acetate, formate, or benzoate) selectively over other competing ions present in solution in significant excess, with an electrosorption capacity in the range of 122-157 mg anions/gcell (polymer and CNT components on the anodic and cathodic side of the cell). The ion sorption capacity of the cell was high even after five adsorption/desorption cycles (18 000 s of continuous operation). In addition, the cell exhibited molecular selectivity even between two carboxylates (e.g., between benzoate and acetate or formate) which differ only in terms of basicity and hydrophobicity. We anticipate that this strategy can be employed as a versatile platform for selective ion separations. In particular, the functionalization of electrochemical cells with the proper polymers would enable the remote and economically viable electro-mediated separation of the desired ionic species in a quantitative and reversible manner.

Superparamagnetic Composites Based on Ionic Resin Beads/CaCO3 /Magnetite.

The preparation of superparamagnetic composites obtained by CaCO3 mineralization from supersaturate aqueous solutions is presented. The preparation was conducted in the presence of oleic acid stabilized magnetite nanoparticles as a water-based magnetic fluid and insoluble templates as gel-like cross-linked polymeric beads. The presence of the magnetic particles in the composites provides a facile way for external manipulation using a permanent magnet, thus allowing the separation and extraction of magnetically modified materials. Two ion exchangers based on divinylbenzene/ethyl acrylate/acrylonitrile cross-linked copolymer-a cation ion exchanger (CIE) and an amphoteric ion exchanger (AIE)-were used, as well as different addition orders of magnetite and CaCO3 crystals growth precursors. The morphology of the composites was investigated by SEM, the polymorphs content by X-ray diffraction, and the thermal stability by thermogravimetric analysis. Polymer, CaCO3 , and magnetite in the composite particles were shown to be present by energy dispersive X-ray (EDX), XPS, and TEM. The sorption capacity for CuII ions was tested, as compared to samples prepared without magnetite.

Synthesis of hierarchically structured materials: microporous diatoms and nanoporous hydroxyaluminosilicate

Diatomite is well known to remove particulate matter for a broad range of applications due to diatom skeleton structures. Hydrothermally treated diatomite has been demonstrated to be a feasible pathway to produce advanced materials for the removal of aqueous heavy metal ions. However, single-synthesis routes to obtain altered diatomite for simultaneous removal of dissolved and particulate contaminants are still missing. Therefore, hydrothermal experiments at pH 12.8 ([KOH] = 0.1 M), and T = 100 °C and different added Al concentrations (0 mM ≤ [Al] ≤ 11 mM) were conducted. Results reveal that in comparison with previous experiments (Hollen et al. in J Mater Sci Eng B 2(10):523–533, 2012) using less alkaline solutions slower dissolution of diatomite is triggering the formation of nanosized spherical particles (NSP) in the presence of diatom skeleton relicts. NSP ranged between 10 and 50 nm in size and were located within the micropores of the diatoms (100–200 nm). TEM-SAED analyses of NSP indicated nanocrystalline phases with distinct lattice planes of 0.45 and 0.26 nm, which could not be attributed to common aluminosilicates. In accordance with the small crystal size, no X-ray diffraction peaks occurred in the bulk reaction product using powder XRD analyses. Metal ion removal experiments at ambient temperature indicated its high removal capacities for aqueous Cu2+, Pb2+ and Zn2+ ranging from 10 to 99 % (e.g., ion sorption capacities of about 0.02–0.2 mval/g). The synthesized product was also successfully tested for its metal ion removal behaviour using a mine drainage solution containing Cd2+, Pb2+, Zn2+ and Sr2+. The developed synthesis path yields a hierarchically structured material based on combined micropores (about 100 nm) from the diatoms and NSP with nanopores (1–5 nm) which is promising for large-scale production to simultaneously remove dissolved and particulate contaminants from aqueous solutions.

Optically transparent silver-loaded mesoporous thin film coating with long-lasting antibacterial activity

Infectious diseases caused by microorganisms affect millions of people worldwide. In an effort to prevent infections induced by bacteria, a variety of antibacterial coatings have been designed. In this sense, the possibility to combine broad-range bactericidal agents such as silver and chemically and mechanically stable matrices such as mesoporous oxide thin films has been encouraging. In this study, titania–silica bilayer mesoporous thin film (MTF) coatings have been produced and loaded with silver species, and their bactericidal efficiency against Pseudomonas aeruginosa and Staphylococcus aureus was assessed over time. In this sense, coatings loaded with silver ions (MTF + Ag+) were analyzed in comparison with coatings confining silver nanoparticles (MTF + AgNP). EDS analysis revealed that both types of MTF coatings were loaded with high amounts of silver (MTF + Ag+ = 25%; MTF + AgNP = 34%). MTF + Ag+ showed extremely high bactericidal efficiency (percent reduction of 99.5 to >99.999) against both strains along 10 cycles of use, comparable to that observed with MTF + AgNP. Interestingly, silver release from both types of coatings was similar over the same testing period. However, contrary to MTF + AgNP, MTF + Ag+ have shown absolute optical transparency. This is relevant for any type of coating, as conservation of optical properties of the material surface where they are intended to be applied, is highly desirable. Moreover, the maximum silver ion sorption capacity of film coatings was 3 μg cm−2 and MTF + Ag+ were still loaded with silver after 10 cycles of use which indicates that the bactericidal effect could be extended beyond. These results spotlight the potentiality of MTF + Ag+ as antibacterial coatings for any ceramic and/or metallic surface with no alteration of optical and mechanical properties.

Functionalized galactoglucomannan‐based hydrogels for the removal of metal cations from aqueous solutions

ABSTRACTNew types of hydrogels derived from O‐acetyl galactoglucomannan (AcGGM) hemicellulose have been synthesized and characterized. The objective of this work was to analyze the sorption capacity (S) of three types of hydrogels containing AcGGM derivatives incorporated into the carboxylic groups of the polymer chain in the AA hydrogel, sulfonic groups in the APA hydrogel, and amide groups in the acrylamide (Aam) hydrogel. These hydrogels are capable of interacting and removing ions such as cadmium [Cd(II)], copper [Cu(II)], lead [Pb(II)], nickel [Ni(II)], and zinc [Zn(II)]. The results show that AA and Aam hydrogels had a lower sorption capacity of ions compared to the APA hydrogel, which had a high sorption capacity. The maximal sorption capacity was determined by the successive enrichment method, obtaining Pb(II) amount of 48.3 mg/g of AA hydrogel, 65.8 mg/g of APA hydrogel, and 40.8 mg/g of Aam hydrogel. Hence, Pb(II) ions are greatly retained by the three hydrogels. These results are promising for the development of new materials with potential applications in metal ion removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44093.

Solvothermal synthesis of mesoporous magnetite nanoparticles for Cr(IV) ions uptake and microwave absorption

Colloidal mesoporous magnetite nanoparticles with tunable porosity were realized by a simple and scalable solvothermal route with the aid of AOT as ligands. AOT was used to induce the anisotropic crystal growth of smaller nanocrystals and restrain their tight aggregation so as to form more mesoscale pores. Morphologies and microstructures investigation by SEM and TEM revealed that the bigger nanoparticles were composed of smaller nanocrystals with an average size of 18 nm. A possible formation mechanism was proposed for the mesoporous nanoparticles. Study of nitrogen adsorption–desorption isotherm revealed that the Brunauer–Emmett–Teller (BET) specific surface area of mesoporous nanoparticles is up to 209 m2/g, resulting from the slit-shaped pores created by the aggregation of polyhedral nanocrystals. Magnetic properties study indicated that the as-prepared nanoparticles are superparamagnetic at room temperature. Optimized mesoporous magnetite nanoparticles exhibit a maximum Cr(VI) ion sorption capacity of 12.9 mmol/g, and its absorption behavior followed a Freundlich model. Microwave absorption study indicated that porous nanoparticles own higher permeability values than that of solid nanoparticles, leading to a higher dielectric loss in the frequency range of 2–18 GHz.