Morphology, Surface Layer Evolution, and Structure–Dye Adsorption Relationship of Porous Fe3O4 MNPs Prepared by Solvothermal/Gas Generation Process
15 Feb 2017-ACS Sustainable Chemistry & Engineering (American Chemical Society)-Vol. 5, Iss: 3, pp 2339-2349
TL;DR: In this article, a new system based on dimethylacetamide, ethanolamine, and azobis(isobutyronitrile) (AIBN) was employed to synthesize porous Fe3O4 magnetic nanoparticles (MNPs) for the first time.
Abstract: A new system based on dimethylacetamide, ethanolamine, and azobis(isobutyronitrile) (AIBN) was employed to synthesize porous Fe3O4 magnetic nanoparticles (MNPs) for the first time. The formation mechanism, morphology, and surface layer evolution of MNPs at the different AIBN ratios were revealed. The MNPs prepared without AIBN showed a randomly assembled morphology with a BET surface area of 174 m2/g, which is almost the highest reported until now. After AIBN was added, N2 gas and radical were produced by the thermal decomposition reaction. The high gas pressure enhanced the growth and self-assembly of nanounits, leading to a microsphere morphology. The radical caused a surface modification effect, which led to a decline in both the specific saturation magnetization and surface area of Fe3O4 MNPs. The surface of MNPs was fully modified when prepared at a high AIBN ratio. The methyl orange (MO) adsorption revealed that the modification coverage and surface composition of Fe3O4 MNPs are responsible for its ...
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TL;DR: In this article, a large scale synthesis of mesoporous hematite (α-Fe2O3) nanorods with a high surface area of 98 m2/g and an average pore size of ∼26 nm was used for adsorption studies for pollutant dye removal.
Abstract: A large scale synthesis of mesoporous hematite (α-Fe2O3) nanorods with a high surface area of 98 m2/g and an average pore size of ∼26 nm was used for adsorption studies for pollutant dye removal. The nanorods exhibited rapid, superior, and selective adsorption efficiency toward Congo red, an organic dye present in wastewater. Highly selective adsorption capability of the mesoporous α-Fe2O3 nanorods has been attributed to the presence of abundant surface active sites with porous networks which make it highly water dispersible facilitating the formation of H-bonding and coordination effect between the -NH2 group of Congo red with its surface -OH groups and Fe3+, respectively. Adsorption studies concerning the effect of contact time, initial dye concentration, dosage of adsorbent, and effect of pH on adsorption kinetics were explored in addition to the desorption process investigation regarding the effect of solution pH from acidic to alkaline. To unravel the unresolved phenomenon toward selective adsorption...
105 citations
TL;DR: Characterization by P-XRD, FE-SEM, and TEM confirm Fe3O4 has a spherical crystalline structure with an average diameter of 15 nm, which after functionalization with BTCA, increases to 20’nm, and the adsorption capacity is 630 mg/g, which is attributed to strong H-bonding ability of BTCA with C.R dye.
Abstract: In this study, the new material Fe3O4@BTCA has been synthesized by immobilization of 1,2,4,5-Benzenetetracarboxylic acid (BTCA) on the surface of Fe3O4 NPs, obtained by co-precipitation of FeCl3.6H2O and FeCl2.4H2O in the basic conditions. Characterization by P-XRD, FE-SEM, and TEM confirm Fe3O4 has a spherical crystalline structure with an average diameter of 15 nm, which after functionalization with BTCA, increases to 20 nm. Functionalization also enhances the surface area and surface charge of the material, confirmed by BET and zeta potential analyses, respectively. The dye adsorption capacity of Fe3O4@BTCA has been investigated for three common dyes; Congo red (C.R), Methylene blue (M.B), and Crystal violet (C.V). The adsorption studies show that the material rapidly and selectively adsorbs C.R dye with very high adsorption capacity (630 mg/g), which is attributed to strong H-bonding ability of BTCA with C.R dye as indicated by adsorption mechanism study. The material also shows excellent recyclability without any considerable loss of adsorption capacity. Adsorption isotherm and kinetic studies suggest that the adsorption occurs by the Langmuir adsorption model following pseudo-second-order adsorption kinetics.
90 citations
TL;DR: It was observed that the synthesized BNNS-Fe3O4 nanocomposite could reduce As(V) ion concentration from 856 ppb in a solution to below 10 ppb (>98.83% removal), which is the permissible limit according to World Health Organization recommendations.
Abstract: It is widely known that the existence of arsenic (As) in water negatively affects humans and the environment. We report the synthesis, characterization, and application of boron nitride nanosheets ...
41 citations
TL;DR: In this article, the authors investigated the organic pollutants adsorption mechanism over network alginate hydrogel beads based on immobilized bio-sourced porous carbon (PC@Fe3O4-NPs@Alginate) and highlights its high extent mass recovery in aqueous media.
41 citations
16 Apr 2018
TL;DR: The procedure kinetics plays an important role in the optimization of membrane modification through chemical reaction and physical coating and shows the best trade-off between the flux and antifouling property.
Abstract: The influences of static and pore-flowing procedures on the surface modification of a polyacrylonitrile (PAN) ultrafiltration membrane through chemical reaction and physical coating were investigated in detail. For chemical modification by ethanolamine, a membrane modified by the pore-flowing procedure showed a higher flux and different morphology. The reasons were explained by two effects: the pore-flowing resistance to the random thermal motion of PAN at high temperatures and different reaction kinetics related to the reactant concentration profile on the interface between the membrane and reaction solution and the kinetic property of the fluid (driving force and miscibility) and reaction (time and rate). For physical coating modification, a dense and flat layer via a loose and random layer was formed during the pore-flowing process and static process, which changed the flux and antifouling property of the membrane. The membrane prepared by dead-end filtration showed the best trade-off between the flux and antifouling property. Overall, the procedure kinetics plays an important role in the optimization of membrane modification.
38 citations
References
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TL;DR: Hollow micro-/nanostructures are of great interest in many current and emerging areas of technology as discussed by the authors, and a comprehensive overview of synthetic strategies for hollow structures is presented.
Abstract: Hollow micro-/nanostructures are of great interest in many current and emerging areas of technology. Perhaps the best-known example of the former is the use of fly-ash hollow particles generated from coal power plants as partial replacement for Portland cement, to produce concrete with enhanced strength and durability. This review is devoted to the progress made in the last decade in synthesis and applications of hollow micro-/nanostructures. We present a comprehensive overview of synthetic strategies for hollow structures. These strategies are broadly categorized into four themes, which include well-established approaches, such as conventional hard-templating and soft-templating methods, as well as newly emerging methods based on sacrificial templating and template-free synthesis. Success in each has inspired multiple variations that continue to drive the rapid evolution of the field. The Review therefore focuses on the fundamentals of each process, pointing out advantages and disadvantages where appropriate. Strategies for generating more complex hollow structures, such as rattle-type and nonspherical hollow structures, are also discussed. Applications of hollow structures in lithium batteries, catalysis and sensing, and biomedical applications are reviewed.
2,767 citations
TL;DR: In this paper, the synthesis of novel 3D flower-like iron oxide nanostructures by an ethylene glycol (EG)-mediated self-assembly process is reported, which can be used to further understand the mechanism of self-organization and expand the applications of IR nanomaterials.
Abstract: 3D nanostructures have attracted much attention because of their unique properties and potential applications. The simplest synthetic route to 3D nanostructures is probably selfassembly, in which ordered aggregates are formed in a spontaneous process. However, it is still a big challenge to develop simple and reliable synthetic methods for hierarchically selfassembled architectures with designed chemical components and controlled morphologies, which strongly affect the properties of nanomaterials. Iron oxides have been extensively studied in diverse fields including catalysis, environment protection, sensors, magnetic storage media, and clinical diagnosis and treatment. Various iron oxide structures, such as nanocrystals, particles, cubes, spindles, rods, wires, tubes, and flakes, have been successfully fabricated by a variety of methods. However, the self-assembly of these low-dimensional building blocks into complex 3D ordered nanostructures is still considerably more difficult. In order to further understand the mechanism of self-organization and expand the applications of iron oxide nanomaterials, self-assembled iron oxide 3D nanostructures need to be explored in more detail. Herein, we report the synthesis of novel 3D flowerlike iron oxide nanostructures by an ethylene glycol (EG)-mediated self-assembly process. Such a method has been adopted previously for the preparation of V2O5 hollow microspheres, [7]
1,508 citations
TL;DR: The functionalized magnetically retrievable catalysts or nanocatalysts that are increasingly being used in catalysis, green chemistry and pharmaceutically significant reactions are summarized in this review.
Abstract: Surface functionalization of nano-magnetic nanoparticles is a well-designed way to bridge the gap between heterogeneous and homogeneous catalysis. The introduction of magnetic nanoparticles (MNPs) in a variety of solid matrices allows the combination of well-known procedures for catalyst heterogenization with techniques for magnetic separation. Magnetite is a well-known material, also known as ferrite (Fe3O4), and can be used as a versatile support for functionalization of metals, organocatalysts, N-heterocyclic carbenes, and chiral catalysts. It is used as a support for important homogeneous catalytically active metals such as Pd, Pt, Cu, Ni, Co, Ir, etc. to obtain stable and magnetically recyclable heterogeneous catalysts. Homogeneous organocatalysts can be successfully decorated with linkers/ligands on the surface of magnetite or alternatively the organocatalysts can be directly immobilized on the surface of magnetite. The functionalized magnetically retrievable catalysts or nanocatalysts that are increasingly being used in catalysis, green chemistry and pharmaceutically significant reactions are summarized in this review.
1,057 citations
TL;DR: Experimental results indicated that CNTs-A have excellent adsorption capacity for methyl orange and methylene blue, and Kinetic regression results shown that the adsorbent kinetic was more accurately represented by a pseudo second-order model than Langmuir isotherm model.
Abstract: An alkali-acitvated method was explored to synthesize activated carbon nanotubes (CNTs-A) with a high specific surface area (SSA), and a large number of mesopores. The resulting CNTs-A were used as an adsorbent material for removal of anionic and cationic dyes in aqueous solutions. Experimental results indicated that CNTs-A have excellent adsorption capacity for methyl orange (149 mg/g) and methylene blue (399 mg/g). Alkali-activation treatment of CNTs increased the SSA and pore volume (PV), and introduced oxygen-containing functional groups on the surface of CNTs-A, which would be beneficial to improving the adsorption affinity of CNTs-A for removal of dyes. Kinetic regression results shown that the adsorption kinetic was more accurately represented by a pseudo second-order model. The overall adsorption process was jointly controlled by external mass transfer and intra-particle diffusion, and intra-particle diffusion played a dominant role. Freundlich isotherm model showed a better fit with adsorption da...
617 citations
TL;DR: In this paper, the effect of different reaction parameters such as initial pH, H2O2 dosage, Fe3O4 nanoparticles addition, initial concentration of 2,4-DCP and temperature on two-stage first-order kinetics of degradation was studied.
Abstract: Fenton-like degradation of 2,4-dichlorophenol (2,4-DCP) in aqueous solution was investigated over Fe3O4 magnetic nanoparticles (MNPs) as catalyst. The obtained samples were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption–desorption isotherms, and physical property measurement system (PPMS). The catalytic results showed that Fe3O4 MNPs presented good properties for the degradation and mineralization of 2,4-DCP, achieving complete decomposition of 2,4-DCP and 51% of TOC removal after 180 min at reaction conditions of H2O2 12 mM, Fe3O4 MNPs 1.0 g/L, 2,4-DCP 100 mg/L, pH 3.0 and T 30 °C. The effect of different reaction parameters such as initial pH, H2O2 dosage, Fe3O4 MNPs addition, initial concentration of 2,4-DCP and temperature on two-stage first-order kinetics of 2,4-DCP degradation was studied. A high utilization efficiency of H2O2 calculated as 73% was observed. According to the analyses of iron leaching, reactive oxidizing species and degradation intermediates, a possible mechanistic steps of 2,4-DCP degradation dominated by OH reactions (especially by free OH in the bulk solution) were proposed. Besides, stability and reusability of Fe3O4 MNPs were tested.
506 citations