Resol/triblock copolymer composite-guided smart fabrication of carbonized mesopores for efficiently decoding exosomal glycans

Soft-template carbonized mesopores were developed for the purpose of enriching urinary exosomal glycans through organic-organic self-assembly using block copolymers and resol precursors. With a high surface area of 229 m² g^-1, a small pore size of 3.1 nm, and a significant amount of carbon that specifically interacts with oligosaccharides in glycans, this carbonized mesopore material exhibits high selectivity and low limits of detection (5 ng μL^-1) towards glycans. Our analysis of complex urine samples from healthy volunteers and bladder carcinoma patients successfully profiled 48 and 56 exosomal glycans, respectively, and 16 of them were significantly changed. Moreover, one upregulated bisecting N-acetylglucosamine (GlcNAc)-type glycan with core fucose, two upregulated and two downregulated terminal-sialylated glycans were revealed to be linked to bladder carcinoma. This approach is of significant importance for understanding diseases that arise from protein glycosylation mutations, and it may contribute to the development of novel diagnostic and therapeutic strategies for bladder carcinoma.

Triple-Peak Photoluminescence of DNA-Hybrid Alq3 Crystals Emitting a Depressed Single Peak upon Bio-Recognition

The green organic semiconductor, tris-(8-hydroxyquinoline)aluminum (Alq₃), was hybridized with DNA growing in the shape of hexagonal prismatic crystals. In this study, we applied hydrodynamic flow to the fabrication of Alq₃ crystals doped with DNA molecules. The hydrodynamic flow in the Taylor-Couette reactor induced nanoscale pores in the Alq₃ crystals, especially at the side part of the particles. The particles exhibited distinctly different photoluminescence emissions divided into three parts compared to common Alq₃-DNA hybrid crystals. We named this particle a "three-photonic-unit". After treatment with complementary target DNA, the three-photonic-unit Alq₃ particles doped with DNAs were found to emit depressed luminescence from side parts of the particles. This novel phenomenon would expand the technological value of these hybrid crystals with divided photoluminescence emissions toward a wider range of bio-photonic applications.

Soft-template solvent thermal method synthesis of magnetic mesoporous carbon-silica composite for adsorption of methyl orange from aqueous solution

A facile soft-template solvent thermal strategy was developed to prepare mesoporous carbon-silica composite (MMCS) by using furfuryl alcohol (FA) as carbon precursor, Pluronic copolymer P123 as template, hydrated iron nitrate as iron source, and teraethylorthosilicate as silicon source and it was applied for the removal of methyl orange (MO). The as-synthesized MMCS with abound of hydrophilic groups processed a high specific surface area, large pore volume, and good magnetic response. With the increased amount of FA, the surface area and functional groups increased, promoting the adsorption effect. The maximum adsorption capacity of MO on MMCS can be high to 113.1 mg g^-1 at pH 4 with 150 mg L^-1 initial MO concentration. The adsorption isotherm, kinetic, and thermodynamics were all studied and the results showed the adsorption process well fitted Langmuir adsorption isotherm and pseudo-second-order model. Additionally, it was shown that the adsorption process could not be interfered by the co-existence of PO₄^3-, NO₃^-, CO₃^2-, SO₄^2-, and real water matrix. And the proposed adsorbent can remove MO in three practical water samples with satisfied removal rates ranging from 92.8 to 99.8%. Thus, the MMCS prepared in this study could be utilized as an alternative adsorbent for the removal of methyl orange from practical aqueous solution.

Temperature-Controlled Selectivity of Hydrogenation and Hydrodeoxygenation of Biomass by Superhydrophilic Nitrogen/Oxygen Co-Doped Porous Carbon Nanosphere Supported Pd Nanoparticles

Selective hydrogenation and hydrodeoxygenation (HDO) of biomass to value-added products play a crucial role in the development of renewable energy resources. However, achieving a temperature-controlled selectivity within one catalytic system while retaining excellent hydrogenation and HDO performance remains a great challenge. Here, nitrogen/oxygen (N/O) co-doped porous carbon nanosphere derived from resin polymer spheres is synthesized as the host matrix to in situ encapsulate highly dispersed Pd nanoparticles (NPs). Through N/O co-doping, the defects on the surface of carbon structure can serve as active sites to promote substrate adsorption. After a facile H₂ O₂ post-treatment process, the presence of abundant carboxyl groups on the porous carbon nanospheres can act as acidic sites to replace the use of acidic additives in the HDO process. Additionally, the increased surface oxygen-containing groups improve hydrophilicity to disperse catalysts in aqueous solutions. Owing to the unique highly dispersed Pd NPs and abundant surface defects, the Pd@APF-H₂ O₂ (2.3 nm) catalysts exhibit excellent catalytic activity and temperature-controlled selectivity for hydrogenation and HDO products of biomass-derived vanillin.

Fabrication of magnetic ordered mesoporous carbon for quantitative analysis of acidic phytohormones in mushroom samples prior to their determination by ultra-high-performance liquid chromatography–tandem mass spectrometry

A novel method was established for analysing trace four acidic phytohormones, namely, indole-3-acetic acid, 3-indolebutyric acid, abscisic acid, and 1-naphthylacetic acid, using magnetic ordered mesoporous carbon (MOMC). MOMC was facilely synthesised via self-assembly strategy with a direct carbonisation process. The properties of MOMC were characterised using various instruments. MOMC exhibited excellent adsorption capacity towards the analytes. Various critical parameters which may influence the enrichment efficiency were evaluated, including amount of MOMC, extraction conditions, and desorption conditions. An efficient method based on MOMC magnetic solid-phase extraction coupled with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was developed to analyse the trace four acidic phytohormones, with good correlation coefficients (R 2 = 0.9965–0.9998) and low limits of detection (0.13–9.7 ng L−1, S/N = 3). Trace acidic phytohormones in Agaricus bisporus and Hypsizygus marmoreus samples were determined with satisfactory recoveries (91.8–108%) and reproducibility (2.6–6.3%). The features indicated that MOMC provides an efficient platform for mushroom sampling; the developed method is convenient, promising, and sensitive for the detection of trace phytohormones in complicated mushroom samples.

Interfacial Assembly and Applications of Functional Mesoporous Materials

Functional mesoporous materials have gained tremendous attention due to their distinctive properties and potential applications. In recent decades, the self-assembly of micelles and framework precursors into mesostructures on the liquid-solid, liquid-liquid, and gas-liquid interface has been explored in the construction of functional mesoporous materials with diverse compositions, morphologies, mesostructures, and pore sizes. Compared with the one-phase solution synthetic approach, the introduction of a two-phase interface in the synthetic system changes self-assembly behaviors between micelles and framework species, leading to the possibility for the on-demand fabrication of unique mesoporous architectures. In addition, controlling the interfacial tension is critical to manipulate the self-assembly process for precise synthesis. In particular, recent breakthroughs based on the concept of the "monomicelles" assembly mechanism are very promising and interesting for the synthesis of functional mesoporous materials with the precise control. In this review, we highlight the synthetic strategies, principles, and interface engineering at the macroscale, microscale, and nanoscale for oriented interfacial assembly of functional mesoporous materials over the past 10 years. The potential applications in various fields, including adsorption, separation, sensors, catalysis, energy storage, solar cells, and biomedicine, are discussed. Finally, we also propose the remaining challenges, possible directions, and opportunities in this field for the future outlook.

Facile one-pot solvothermal synthesis of magnetic mesoporous carbon for the efficient adsorption of methyl orange

A facile one-pot solvent thermal method was proposed to synthesize magnetic mesoporous carbon (MMC) using Fe(NO₃)₃·9H₂O as a precursor, Pluronic copolymer P123 as template, and chitosan as carbon source, and it was applied for the adsorptive remediation of methyl orange (MO). The characterization results of TEM, XRD, and IR showed that MMC consisted of graphitized carbon matrix and some black spherical particle mixture of Fe₃O₄ and Fe, and it was rich in hydroxyl and carbonyl groups. Besides, the effect of the content of Fe and the content of chitosan in MMC on the magnetism and adsorption performance of prepared material were investigated. In addition, the effects of pH value, initial concentration of methyl orange, and contact time on the adsorption performance of MO were studied, respectively. At 318 K, the maximum adsorption capacity of MO calculated from Langmuir isotherm was from 139 to 400 mg g^-1 on MMC. Kinetic studies demonstrated that the adsorption process obeyed a pseudo-second-order kinetic model. The regeneration experiments revealed that MMC could be reused at least five times without notable decrease of adsorption performance. These results illustrate that MMC is an efficient and economical adsorbent for the adsorption of MO.

Palladium nanoparticles embedded in mesoporous carbons as efficient, green and reusable catalysts for mild hydrogenations of nitroarenes

The reduction of nitroarenes is the most efficient route for the preparation of aromatic primary amines. These reductions are generally performed in the presence of heterogeneous transition metal catalysts, which are rather efficient but long and tedious to prepare. In addition, they contain very expensive metals that are in most cases difficult to reuse. Therefore, the development of efficient, easily accessible and reusable Pd catalysts obtained rapidly from safe and non-toxic starting materials was implemented in this report. Two bottom-up synthesis methods were used, the first consisted in the impregnation of a micro/mesoporous carbon support with a Pd salt solution, followed by thermal reduction (at 300, 450 or 600 °C) while the second involved a direct synthesis based on the co-assembly and pyrolysis (600 °C) of a mixture of a phenolic precursor, glyoxal, a surfactant and a Pd salt. The obtained composites possess Pd nanoparticles (NPs) of tunable sizes (ranging from 1–2 to 7.0 nm) and homogeneously distributed in the carbon framework (pores/walls). It turned out that they were successfully used for mild and environment-friendly hydrogenations of nitroarenes at room temperature under H₂ (1 atm) in EtOH in the presence of only 5 mequiv. of supported Pd. The determinations of the optimal characteristics of the catalysts constituted a second objective of this study. It was found that the activity of the catalysts was strongly dependent on the Pd NPs sizes, i.e., catalysts bearing small Pd NPs (1.2 nm obtained at 300 °C and 3.4 nm obtained at 450 °C) exhibited an excellent activity, while those containing larger Pd NPs (6.4 nm and 7.0 nm obtained at 600 °C, either by indirect or direct methods) were not active. Moreover, the possibility to reuse the catalysts was shown to be dependent on the surface chemistry of the Pd NPs: the smallest Pd NPs are prone to oxidation by air and their surface was gradually covered by a PdO shell decreasing their activity during reuse. A good compromise between intrinsic catalytic activity (i.e. during first use) and possibility of reuse was found in the catalyst made by impregnation followed by reduction at 450 °C since the hydrogenation could be performed in only 2 h in EtOH or even in water. The catalyst was quantitatively recovered after reaction by filtration, used at least 7 times with no loss of efficiency. Advantageously, almost Pd-free primary aromatic amines were obtained since the Pd leaching was very low (<0.1% of the introduced amount). Compared to numerous reports from the literature, the catalysts described here were both easily accessible from eco-friendly precursors and very active for hydrogenations under mild and “green” reaction conditions.

Size induced activity and reusability of mesoporous carbons containing Pd NPs are demonstrated herein for mild and green hydrogenations of nitroarenes.

Nickel nanoparticles inlaid in lignin-derived carbon as high effective catalyst for lignin depolymerization

Ni nanoparticles inlaid in lignin-derived carbon constructing the "inlaid type" Ni/C-I was reported to improve stability and adjust metal-support interaction of lignin hydrogenolysis catalyst. The Ni/C-I was further heat treated in air to prepare Ni/C-R so as to re-expose the blocked active sites by carbon species. A lot of characterization techniques were carried out to confirm the "inlaid structure" of the catalysts. The lignin depolymerization results demonstrated that the Ni/C-R had better catalytic performance than traditional "supported type" Ni/C, 23.3% aromatic monomer yield and 82.4% bio-oil yield were achieved. Moreover, the mechanism studies with lignin model compound revealed that Ni/C-R had better bond breaking ability than Ni/C, even CC bond could be cleaved. The electron effect could be responsible for that, since the electrons could transfer from Ni⁰ to carbon support for Ni/C-R, which could improve the bond breaking ability.

Magnetic Mesoporous Carbons Derived from in Situ MgO Template Formation for Fast Removal of Heavy Metal Ions

In this paper, magnetic mesoporous carbon composites were prepared by calcination of the mixture of magnesium citrate and Fe₃O₄@SiO₂ in an inert atmosphere. A high content of Fe₃O₄@SiO₂ and MgO was in situ embedded in a carbon matrix. After removing the MgO template by diluted acid, the resulting material (Fe₃O₄@SiO₂@mC) was subjected to further H₂O₂ oxidation treatment. The formed oxygen-containing functional groups on the products provided plenty of active sites for the adsorption of analytes of interest. The obtained composites (Fe₃O₄@SiO₂@mC-H₂O₂) exhibited a mesoporous structure with a high specific surface area of 731 m² g^-1. The adsorption capacities of Fe₃O₄@SiO₂@mC-H₂O₂ for Cu(II) and Pb(II) were calculated to be 86.5 and 156 mg g^-1, respectively. Under optimal conditions, the adsorption isotherm of Cu(II) and Pb(II) onto Fe₃O₄@SiO₂@mC-H₂O₂ fitted the Langmuir model and the adsorption kinetic was well-correlated with the pseudo-second-order model. Besides, Fe₃O₄@SiO₂@mC-H₂O₂ exhibited fast removal dynamics (within less than 1 min) for Cu(II) and Pb(II), demonstrating great application potential in wastewater treatment.

Highly stable mesoporous silica nanospheres embedded with FeCo/graphitic shell nanocrystals as magnetically recyclable multifunctional adsorbents for wastewater treatment

We report the first synthesis of highly stable and efficiently recyclable multifunctional adsorbents containing FeCo/GC nanoparticles with the strongest magnetic properties.

Ordered Mesoporous Carbonaceous Materials with Tunable Surface Property for Enrichment of Hexachlorobenzene

A gradient pyrolysis approach has been adopted for synthesis of ordered mesoporous carbonaceous materials with different surface and textural properties for removal of hexachlorobenzene. The resultant ordered mesoporous carbonaceous materials possess high surface areas (364-888 m²/g), large pore volumes (0.23-0.47 cm³/g), uniform pore sizes (2.6-3.8 nm), and tunable hydrophobic properties. They show high-efficiency removal performances for hexachlorobenzene with high adsorption capacity of 594.2-992.1 μg/g. An enhanced removal rate (>99%) can be obtained with the increasing pyrolysis temperature (900 °C) as a result of the strong hydrophobic-hydrophobic interaction between the carbon framework and hexachlorobenzene molecules. Furthermore, the adsorption behaviors follow the Sips isotherm model and obey the pseudo-first-order kinetic model.

Carbothermal synthesis of ordered mesoporous carbon-supported nano zero-valent iron with enhanced stability and activity for hexavalent chromium reduction

Composites of nano zero-valent iron (nZVI) and ordered mesoporous carbon (OMC) are prepared by using simultaneous carbothermal reduction methods. The reactivity and stability of nZVI are expected to be enhanced by embedding it in the ordered pore channels. The structure characteristics of nZVI/OMC and the removal pathway for hexavalent chromium (Cr(VI)) by nZVI/OMC are investigated. Results show that nZVI/OMC with a surface area of 715.16 m(2) g(-1) is obtained at 900 °C. nZVI with particle sizes of 20-30 nm is uniformly embedded in the OMC skeleton. The stability of nZVI is enhanced by surrounding it with a broad carbon layer and a little γ-Fe is derived from the passivation of α-Fe. Detection of ferric state (Fe 2p3/2, around 711.2eV) species confirms that part of the nZVI on the outer surface is inevitably oxidized by O2, even when unused. The removal efficiency of Cr(VI) (50 mg L(-1)) by nZVI/OMC is near 99% within 10 min through reduction (dominant mechanism) and adsorption. nZVI/OMC has the advantage in removal efficiency and reusability in comparison to nZVI/C, OMC and nZVI. This study suggests that nZVI/OMC has the potential for remediation of heavy metal pollution in water.

Synthesis, characterization and dye removal capacities of N-doped mesoporous carbons

Nitrogen-doped ordered mesoporous carbons were synthesized by chemical vapor deposition, using acetonitrile as carbon and nitrogen source and SBA-15 as mesoporous silica template. Their porous texture, structural order and surface chemistry were studied as a function of the experimental conditions (acetonitrile stream concentration and deposition time). A non-doped ordered mesoporous carbon was also prepared by the same procedure using propylene as carbon source. Methylene blue, methyl orange and fuchsin acid were selected as probe molecules to investigate the dye adsorption behavior on the ordered mesoporous carbons. Both N-doped and non-doped ordered mesoporous carbons adsorbed large amounts of these three dyes demonstrating the importance of mesoporosity, especially for the adsorption of larger dyes (e.g. fuchsin acid). The presence of nitrogen functional groups was detrimental for the adsorption of the basic dye (methylene blue). On the other hand, the nitrogen functionalities improved the adsorption kinetics for both acid and basic dyes, and the N-doped samples achieved 100% of their maximum adsorption capacities in less than 15 min.

Hydrophilic modification of ordered mesoporous carbon supported Fe nanoparticles with enhanced adsorption and heterogeneous Fenton-like oxidation performance

Ordered mesoporous carbon with Fe nanoparticles (Fe/meso-C) underwent hydrophilic surface modification with hydrogen peroxide, which shows enhanced adsorption and heterogeneous Fenton oxidation performance for methylene blue.

Magnetic γ-Fe2O3, Fe3O4, and Fe nanoparticles confined within ordered mesoporous carbons as efficient microwave absorbers

A series of magnetic γ-Fe₂O₃, Fe₃O₄, and Fe nanoparticles have been successfully introduced into ordered mesoporous carbons as efficient microwave absorbers.

Carbon monolith with embedded mesopores and nanoparticles as a novel adsorbent for water treatment

Mesoporous carbon nanocomposites, synthesized from natural woodviaa catalytic graphitization reaction, show excellent adsorption of toxic pollutants from water.

Mesoporous carbons: recent advances in synthesis and typical applications

Mesoporous carbon materials have been extensively studied because of their vast potential applications ranging from separation and adsorption, catalysis, and electrochemistry to energy storage.

Environmental performances of hydrochar-derived magnetic carbon composite affected by its carbonaceous precursor

Strong linear correlations were obtained between hydrochar properties and the environmental performances of its derived magnetic carbon composites.

Iron-oxide-supported nanocarbon in lithium-ion batteries, medical, catalytic, and environmental applications

Owing to the three different orbital hybridizations carbon can adopt, the existence of various carbon nanoallotropes differing also in dimensionality has been already affirmed with other structures predicted and expected to emerge in the future. Despite numerous unique features and applications of 2D graphene, 1D carbon nanotubes, or 0D fullerenes, nanodiamonds, and carbon quantum dots, which have been already heavily explored, any of the existing carbon allotropes do not offer competitive magnetic properties. For challenging applications, carbon nanoallotropes are functionalized with magnetic species, especially of iron oxide nature, due to their interesting magnetic properties (superparamagnetism and strong magnetic response under external magnetic fields), easy availability, biocompatibility, and low cost. In addition, combination of iron oxides (magnetite, maghemite, hematite) and carbon nanostructures brings enhanced electrochemical performance and (photo)catalytic capability due to synergetic and cooperative effects. This work aims at reviewing these advanced applications of iron-oxide-supported nanocarbon composites where iron oxides play a diverse role. Various architectures of carbon/iron oxide nanocomposites, their synthetic procedures, physicochemical properties, and applications are discussed in details. A special attention is devoted to hybrids of carbon nanotubes and rare forms (mesoporous carbon, nanofoam) with magnetic iron oxide carriers for advanced environmental technologies. The review also covers the huge application potential of graphene/iron oxide nanocomposites in the field of energy storage, biomedicine, and remediation of environment. Among various discussed medical applications, magnetic composites of zero-dimensional fullerenes and carbon dots are emphasized as promising candidates for complex theranostics and dual magneto-fluorescence imaging.

Direct synthesis of MOF-derived nanoporous carbon with magnetic Co nanoparticles toward efficient water treatment

Nanoporous carbon particles with magnetic Co nanoparticles (Co/NPC particles) are synthesized by one-step carbonization of zeolitic imidazolate framework-67 (ZIF-67) crystals. After the carbonization, the original ZIF-67 shapes are preserved well. Fine magnetic Co nanoparticles are well dispersed in the nanoporous carbon matrix, with the result that the Co/NPC particles show a strong magnetic response. The obtained nanoporous carbons show a high surface area and well-developed graphitized wall, thereby realizing fast molecular diffusion of methylene blue (MB) molecules with excellent adsorption performance. The Co/NPC possesses an impressive saturation capacity for MB dye compared with the commercial activated carbon. Also, the dispersed magnetic Co nanoparticles facilitate easy magnetic separation.

Hierarchical co-assembly avenue to uniform rhombododecahedral magnetic mesoporous graphitic composites

Magnetic nanoparticles have been widely investigated due to their environmental and biomedical applications. However, the unavoidable problems associated with them are their intrinsic instability and the trend of the agglomeration. Mesoporous carbon is considered as an ideal matrix for the protection of magnetic nanoparticles owing to its high surface area, excellent chemical and thermal stability. The preparation of morphology defined composites of magnetic nanoparticles and mesoporous carbon is of great importance for their practical applications. In this work, magnetic mesoporous graphitic composites (MMGCs) with defined rhombododecahedral morphology are fabricated by the pyrolysis of the composites from the hierarchical co-assembly of amphiphilic triblock copolymer, resol oligomers and Fe3O4 nanoparticles. MMGCs exhibit narrow bimodal pore size distribution, high surface area and highly stable magnetic properties, which provide them excellent adsorption ability for the removal of organic contaminants in aqueous solution.

Mesoporous carbon coated molybdenum oxide nanobelts for improved lithium ion storage

Mesoporous carbon-coated molybdenum oxide nanobelt composites were synthesized hydrothermally with subsequent organic–organic assembly and calcination, and used as Li-ion-battery anodes.

Simple Cocasting Method to Prepare Magnetic Mesoporous FePt/C Composites and Their Protein Adsorption Property

A simple cocasting method has been developed to prepare magnetic mesoporous FePt/C composites with superparamagnetic FePt nanoparticles embedded in carbon walls. Furfuryl alcohol, iron(III) acetylacetonate (Fe(acac)3), and platinum(II) acetylacetonate (Pt(acac)2) were used as the carbon and FePt nanoparticle precursors to be simultaneously incorporated into the channels of mesoporous silica SBA-15 template by the incipient wetness impregnation technique. After the polymerization of furfuryl alcohol, the carbonization in argon, and the removal of silica template, magnetic mesoporous FePt/C composites were finally obtained. Magnetic mesoporous FePt/C composites have high surface area of 1244 m2/g and narrow mesopore size distribution peaked at 4.93 nm. FePt nanoparticles were well embedded in mesoporous carbon walls, and mesoporous FePt/C composites exhibit superparamagnetic behavior. Using cytochrome c (Cyt c), myoglobin (Mb), and bovine serum albumin (BSA) as model proteins, the adsorption capacities of Cyt c, Mb, and BSA on magnetic mesoporous FePt/C composites can reach ca. 200, 162, and 121 μg/mg, respectively. These results indicated that mesoporous FePt/C composites have potential as magnetically separable adsorbent for biomolecules separation.

Direct synthesis of ordered mesoporous carbons

Ordered mesoporous carbon materials have recently aroused great research interest because of their widespread applications in many areas such as adsorbents, catalysts and supports, gas storage hosts, and electrode materials. The direct synthesis strategy from organic-organic self-assembly involving the combination of polymerizable precursors and block copolymer templates is expected to be more flexible in preparing mesoporous carbons, compared with the traditional nanocasting strategy of complicated and high-cost procedures using mesoporous silica materials as the hard template. In this review, we present the fundamentals and recent advances related to the field of ordered mesoporous carbon materials from the direct synthesis strategy of block copolymer soft-templating, with a focus on their controllable preparation, modification and potential applications. Under the guidance of their formation mechanism, the preparation of ordered mesoporous carbons are discussed in detail by consulting different experimental conditions, including synthetic pathways, precursors, catalysts and templates. Both the mesopore size and morphology control are introduced. The potential applications of pure mesoporous carbons, nonmetallic- and metallic-modified mesoporous carbons, and some interpenetrating carbon-based composites are demonstrated. Furthermore, remarks on the challenges and perspectives of research directions are proposed for further development of the ordered mesoporous carbons (232 references).

Synthesis of porous carbon balls from spherical colloidal crystal templates

Spherical inverse opal (IO) porous carbon was produced utilizing silica colloidal crystal spheres as templates. The spherical colloidal crystals were obtained through the self-assembly of monodisperse particles inside an emulsion droplet with confined geometry. The templates were inverted using a carbon precursor, phenol-formaldehyde (PF) resol. We demonstrated a two-step synthesis involving the subsequent infiltration of the PF resol precursor into the spherical colloidal crystal template and a one-step synthesis using a silica colloidal solution containing dissolved PF resol. In the former case, the sizes of the IO carbon balls were controlled by the size of the colloidal crystal templates, and diameters of a few micrometers up to 50 μm were obtained. The average diameter of the macropores created by the silica particles was 230 nm. Moreover, meso-/macroporous IO carbon balls were created using block-copolymer templates in the PF resol. In the one-step synthesis, the concentration of PF resol in the colloidal solution controlled the diameter of the IO carbon balls. IO balls smaller than 3 μm were obtained from the direct addition of 5% PF resol. The one-step synthesis produced rather irregular porous structures reflecting the less ordered crystallization processes inside the spherical colloidal crystals. Nitrogen adsorption and cyclic voltammetry measurements were conducted to measure the specific area and electroactive surface area of the IO carbon balls. The specific area of the mesopores-incorporated IO carbon balls was 1.3 times higher than that of bare IO carbon balls. Accordingly, the meso-/macroporous porous carbon balls exhibited higher electrocatalytic properties than the macroporous carbon balls.

High capacity magnetic mesoporous carbon-cobalt composite adsorbents for removal of methylene green from aqueous solutions

Mesoporous carbons containing cobalt nanoparticles are synthesized by tri-or quad-constituent self assembly of Pluronic F127, phenol-formaldehyde oligomer (resol), cobalt acetylacetonate (acac), and optionally tetraethyl orthosilicate (TEOS, optional). Upon pyrolysis in N(2) atmosphere, the resol provides sufficient carbon yield to maintain the ordered structure, while decomposition of the Co(acac) yields cobalt nanoparticles. To provide increased surface area, the dispersed silicate from condensation of TEOS can be etched after carbonization to yield micropores, Without silica templated micropores, the surface area decreases as the cobalt content increases, but there is a concurrent increase in the volume-average pore diameter (BHJ) and a dramatic increase in the adsorption capacity of methylene green with the equilibrium adsorption capacity from 2 to 90 mg/g with increasing Co content. Moreover, the surface area and pore size of mesoporous composites can be dramatically increased by addition of TEOS and subsequent etching. These composites exhibit extremely high adsorption capacity up to 1151 mg/g, which also increases with increases in the Co content. Additionally, the inclusion of cobalt nanoparticles provides magnetic separation from aqueous suspension. The in situ synthesis of the Co nanoparticles yields to a carbon shell that can partially protect the Co from leaching in acidic media; after 96 h in 2 M HCl, the powders remain magnetic.

Simple synthesis of Ni-containing ordered mesoporous carbons and their adsorption/desorption of methylene orange

A simple route has been developed to synthesize magnetic Ni-containing ordered mesoporous carbons (Ni/OMCs) without using a solvent for dissolving carbon precursor or magnetic source. The adsorption and desorption of methylene orange (MO) on the obtained Ni/OMCs were investigated. The effects of Ni(NO(3))(2) loading amount and carbonization temperature on the morphologies, the structural parameters and magnetic properties of these Ni/OMCs were evaluated by X-ray diffraction(XRD), N(2) sorption analysis, transmission electron microscopy(TEM) and physical property measurements. With the increase of Ni(NO(3))(2) loading amount, the ordering of the mesoporous structures, the specific surface area and the total pore volumes of Ni/OMCs decreased, but the pore diameters of Ni/OMCs and the sizes of Ni particle increased. The saturation magnetization strength could be easily adjusted by varying the amount of Ni(NO(3))(2). The specific surface area and total pore volumes decreased with the increasing of carbonization temperature. The size of Ni particle was the biggest at 750°C. The adsorption of MO into Ni/OMCs followed the Sips adsorption model. More interestingly, a simple equation was obtained and was proved to well fit the desorption behavior of MO on Ni/OMCs. The values for the relative fitted parameters were obtained and the physical meanings of the parameters were well defined.

Synthesis and characterization of γ-Fe2O3/carbon hybrids and their application in removal of hexavalent chromium ions from aqueous solutions

Magnetic Fe(2)O(3)/carbon hybrids were prepared in a two-step process. First, acetic acid vapor interacted with iron cations dispersed on the surface of a nanocasted ordered mesoporous carbon (CMK-3). In the second step, the primarily created iron acetate species underwent pyrolysis and transformed to magnetic iron oxide nanoparticles. X-ray diffraction, Fourier-transform infrared, and Raman spectroscopies were used for the chemical and structural characterization of the hybrids, while surface area measurements, thermal analysis, and transmission electron microscopy were employed to determine their physical, surface, and textural properties. These results revealed the preservation of the host carbon structure, which was homogenously and controllably loaded (up to 27 wt %) with nanosized (ca. 20 nm) iron oxides inside the mesoporous system. Mössbauer spectroscopy and magnetic measurements at low temperatures confirmed the formation of γ-Fe(2)O(3) nanoparticles exhibiting superparamagnetic behavior. The kinetic studies showed a rapid removal of Cr(VI) ions from the aqueous solutions in the presence of these magnetic mesoporous hybrids and a considerably increased adsorption capacity per unit mass of sorbent in comparison to that of pristine CMK-3 carbon. The results also indicate highly pH-dependent sorption efficiency of the hybrids, whereas their kinetics was described by a pseudo-second-order kinetic model. Taking into account the simplicity of the synthetic procedure and possibility of magnetic separation of hybrids with immobilized pollutant, the developed mesoporous nanomaterials have quite real potential for applications in water treatment technologies.