Surface Of Carbon Microspheres Research Articles

Synthesis of carbon microsphere-supported nano-zero-valent iron sulfide for enhanced removal of Cr(VI) and p-nitrophenol complex contamination in peroxymonosulfate system

Carbon microspheres supported sulfurized nano zero-valent iron (CMS@S-nFe0) was successfully prepared. The interaction impact of different dosages on the removal of Cr(VI) and p-nitrophenol (PNP) complex contamination was explored by response surface method (RSM). The results showed both the C group and Fe2+ on the surface of carbon microspheres could be used as activators of peroxymonosulfate (PMS) decomposition, and •OH and SO4•- could be produced to promote the oxidative degradation of PNP. Among them, SO4•- was the main reactive oxygen species. The presence of PNP could further promote the reduction of Cr(VI). Besides, loading nFe0 and FeS compounds on the carbon base could significantly reduce the production of free iron ions, which could effectively remove Cr(VI) and PNP from polluted water. In terms of treatment results, CMS@S- nFe0 was a promising material for wastewater treatment because of its excellent performance in adsorption of heavy metals and degradation of organic pollutants.

Polythiophene/Carbon Microsphere Composite as a High-performance Cathode Material for Aluminium-ion Batteries

Due to the high theoretical volume specific capacity and mass specific capacity of aluminum-ion batteries, they can meet the needs of contemporary society for high-performance energy storage devices, and have attracted a lot of research strength. Cathode materials are a key issue limiting the development of aluminum-ion batteries. Herein, polythiophene was prepared on the surface of carbon microspheres by in-situ oxidative polymerization, resulting in polythiophene carbon microsphere composite materials. It exhibits excellent electrochemical performance, as a cathode material for aluminum-ion batteries, in terms of a high specific capacity (106 mAh g−1 at a current density of 1 A g−1), good stability (maintaining 58 % of initial capacity after 10000 cycles) and excellent rate performance (90 mAh g−1 at a high current density of 3.5 A g−1).

Effect of Functionalized Carbon Microspheres Combined with Ammonium Polyphosphate on Fire Safety Performance of Thermoplastic Polyurethane.

In this article, carbon microspheres (CMSs) synthesized by the hydrothermal method and CMSs-Fe (with Fe3+ adsorbed on the surface of CMSs) were combined with ammonium polyphosphate (APP) to achieve the fire safety improvement of thermoplastic polyurethane (TPU). The fire safety performance of TPU composites was investigated by the cone calorimeter test, microscale combustion calorimeter test, thermogravimetric analysis/infrared spectrometry, Raman spectrometry, X-ray photoelectron spectroscopy, and scanning electron microscopy. The results showed that CMSs and CMSs-Fe can improve the fire safety performance of TPU/APP composites and the effect of CMSs-Fe was better than that of CMSs. The peak heat release rate of the sample containing 0.25 wt % CMSs and 7.75 wt % APP was 16.7% lower than that of the sample containing 8.00 wt % APP, and the content of toxic gases was also reduced in the fire smoke. Also, total heat release and total smoke release of the sample containing CMSs-Fe were 54.7% and 11.6%, respectively, lower than those of the sample containing 0.25% CMSs. It confirmed the contribution of CMSs to the flame retardant system, and the performance of CMSs is improved by adsorbing Fe3+.

Hydrothermal synthesis of carbon microspheres from sucrose with citric acid as a catalyst: physicochemical and structural properties

The production of size-tunable Carbon microspheres (CMSs) from cheaply available materials using an environmentally friendly technique is highly appreciated. In this study, size-tunable CMSs were hydrothermally synthesized at 190°C using sucrose as carbon source, and citric acid as a catalyst. The effect of varying citric acid concentration on the size of the microspheres was investigated. Results indicated that under similar hydrothermal conditions, variation in the concentration of citric acid between 0 and 5 wt.% increased the size of CMSs ranging from 3.12 to 11.2 µm, as evidenced by SEM and particle size analyzer. TGA confirmed the purity of the carbonaceous particles in a single-step degradation with the presence of D-band and G-band in Raman spectra. FTIR and elemental analyzer confirmed the presence of hydrophilic oxygen functionalities such as –OH, –C=O, and COOH on the surface of CMSs. This study opens a novel and straightforward approach to produce size-tunable CMSs with functional groups.

Construction of flame retardant coating on polyester fabric with ammonium polyphosphate and carbon microspheres

In this study, ammonium polyphosphate (APP) was coated on the surface of carbon microspheres (CMSs) to synthesize the CMSs-APP (CA) three-in-one intumescent flame retardant (IFR). Then, CA was coated the surface of polyester fabric (CAP) by flame retardant finishing method to improve the flame retardant of polyester fabric. Morphology, thermal, flame retardant and other properties of CAP was characterized by SEM, TG, LOI, UL94 and CONE. The results show that when two layers of flame retardant (CMSs-APP) coated on polyester fabric (CAP2), the LOI value of CAP2 was 28.1% and the burning rating reached B1 class with no droplet drop during the UL94 test. The residue char has increased by 22.2%. The CA coating significantly reduced the heat release rate (HRR) and total heat release (THR) of the polyester fabric, with the HRR reduced by 51.0%, and produced a more stable and compact carbon layer during combustion. Moreover, the coated polyester fabric has excellent washing durability. Overall, CA flame retardant was coated the surface of polyester fabric endowed the polyester fabric with good flame retardant, broadening its scope of application.

Electrochemistry of hydrogen peroxide reduction reaction on carbon paste electrodes modified by Ag- and Pt-supported carbon microspheres

A simple and facile hydrothermal methodology for preparation of carbon microspheres supported with silver or platinum is presented. Electrocatalytic properties of modified carbon microspheres are tested against the electrochemical reduction reaction of hydrogen peroxide. As revealed by transmission electron microscopy, silver and platinum are immobilized on the surface of carbon microspheres in a form of nanoparticles. In addition, scanning electron microscopy reveals coexistence of smooth surface spherical-shaped carbon microspheres together with clusters that resemble a bunch-of-grapes. Carbon paste electrodes in combination with cyclic and square-wave voltammetry are used to study electrocatalytic properties of carbon microspheres. Voltammetric data are analyzed in light of the theory for simple irreversible electrode reaction. Correlation between experimental and theoretical data implies the highest electrocatalytic effect in the case of silver-modified carbon microspheres, though the electrode mechanism is more complex than theoretically predicted.

Lignosulfonate-Directed Synthesis of Consubstantial Yolk–Shell Carbon Microspheres with Pollen-Like Surface from Sugar Biomass

The carbon materials with diverse morphologies and structures have attracted much interest for various applications. In this work, by introducing lignosulfonate with PEO-PPO-PEO triblock copolymer P123 as soft templates, unique yolk–shell structure with pollen-like surface of carbon microspheres were innovatively synthesized using xylose as the carbon precursor under hydrothermal carbonization. A mechanism for the yolk–shell carbon microspheres formation was proposed. The associations between lignosulfonate and P123 led to the formation of mixed micelles. Owing to the highly branched structure and steric hindrance effect of lignosulfonate, lignosulfonate preferentially assembled at the outer position of double layers of micelles, while linear structure P123 located at the inner position. The xylose assembly process depended on the hydrogen bond interactions between xylose and P123/lignosulfonate soft templates, which do provide appropriate nucleation and growth sites for the assembled particles and affect...

Insight into efficient co-removal of Se(IV) and Cr(VI) by magnetic mesoporous carbon microspheres: Performance and mechanism

In this study, carbon microspheres (CMSs) and magnetic carbon microspheres (MCMSs) were synthesized and applied to remove Se(IV) and Cr(VI) in Se(IV), Cr(VI), and Se(IV)-Cr(VI) coexisting systems, respectively. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Vibrating-sample magnetometry (VSM), and X-ray diffraction (XRD) were employed to investigate the physical properties, compositions, and structures of CMSs and MCMSs. X-ray photoelectron spectroscopy (XPS) was employed to reveal the removal mechanism of Se(IV) and Cr(VI) with MCMSs. Under optimum conditions, 100% Se(IV) and 100% Cr(VI) can be removed by MCMSs in 120 min from Se(IV)-Cr(VI) coexisting system containing initial concentration of 10.0 mg/L Se(IV) and 10.0 mg/L Cr(VI). Cr(VI) was removed due to the hydrogen bonding interaction between Cr(VI) and carboxylate groups and redox reaction of Cr(VI) with alcoholic hydroxyl groups on CMSs. Besides, the Fe3O4 nanoscale particles on the surface of CMSs can form outer-sphere complexes with Cr(VI) and reduce Cr(VI) to Cr(III). Se(IV) can form precipitates with the generated Cr(III). Moreover, the Fe3O4 nanoscale particles can form inner-sphere complexes with Se(IV) and reduce Se(IV) to elemental selenium (Se0) by Fe(II).

Enhanced photocatalytic activity of sea-urchin-like carbon/ZnO micro/nano heterostructures

Large scale sea-urchin-like carbon/ZnO heterostructures were successfully synthesized using a novel low temperature hydrothermal method, in which glucose and zinc acetate were employed as carbon and ZnO sources, respectively. ZnO nanowires with an average diameter of 40–50 nm were grown on the surface of carbon microspheres forming carbon/ZnO hybrid nano/micro heterostructures. Owing to the large surface area, superior conductivity, and strong light absorption in the ultraviolet region, the hybrid nano/micro heterostructures showed excellent photocatalytic efficiency for the degradation of methylene orange under ultraviolet light irradiation.

Waxberry-like carbon@polyaniline microspheres with high-performance microwave absorption

Polyaniline (PANI) nanorod arrays were facilely grown on the surface of carbon microspheres via a simple dilute polymerization. The as-synthesized carbon@polyaniline nanorod arrays microspheres (C@PANI) show specific waxberry-like shape, and exhibit superior microwave absorption capacities compared with pure PANI and carbon microsphere. The minimum reflection loss (RL) value of C@PANI microspheres reaches −59.6dB at 15.5GHz with a thin thickness of 2.2mm and the effective bandwidth (reflection loss values of less than −10dB) is as wide as 5.4GHz (from 12.6 to 18GHz). The in-depth analyses of the geometrical shape and composition relationship demonstrate that the enhanced microwave absorption properties of C@PANI microspheres was mainly correlate with the unique PANI nanorod arrays and synergistic effect.

Coating magnesium hydroxide on surface of carbon microspheres and interface binding with poly (ethylene terephthalate) matrix

In this account, magnesium hydroxide (MH) employed as a capsule wall was firstly coated on the surface of carbon microspheres (CMSs) to obtain MH@CMSs using liquid phase deposition, then was modified by 3-Aminopropyltriethoxysilane (APTS) to form FMH@CMSs. To investigate the interface binding forces, a series of PET composites was prepared by melt compounding with MH@CMSs or FMH@CMSs. Field-emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Fourier-transform Infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, chemical structure, and effect of functionalization of CMSs. The coating degree and thermal stability were investigated by thermogravimetry analysis. The results showed that CMSs were coated by an inorganic shell layer of MH as a capsule wall. On the other hand, MH@CMSs were coated with an organic layer of APTS. When compared to MH@CMSs, the interface binding forces between FMH@CMSs and PET matrix were significantly improved, and the tensile strength of FMH@CMSs/PET was higher than that of MH@CMSs/PET. At 1wt% mass fraction of FMH@CMSs, the limiting oxygen index (LOI) value of PET composites increased from 21% to 27.6% following a V-0 rating. The tensile strength of FMH@CMSs/PET increased by 66.2% to reach 47.20MPa, a value nearly similar to that of PET. Overall, the formed two layers provided the FMH@CMSs/PET with good mechanical and flame-retardant properties, which would broaden their scope of application.

Removal mechanism of selenite by Fe3O4-precipitated mesoporous magnetic carbon microspheres

A mesoporous composite of magnetic carbon microspheres (MCMSs) was synthesized via introducing Fe3O4 nanoscale particles to the surface of carbon microspheres (CMSs) by coprecipitation. Scanning electron microscopy and transmission electron microscopy showed the Fe3O4 nanoscale particles were dispersedly immobilized on the surface of CMSs. The MCMSs demonstrated effective removal of selenite (Se(IV)) from wastewater. MCMSs showed the regular pattern where the lower pH value, the lower residual Se(IV) concentration. The coexisting sulfate, nitrate, chloride, carbonate, and silicate had no significant effect on Se(IV) removal, whereas phosphate hindered the removal of Se(IV) by competing with Se(IV) and formed inner–sphere complexes with Fe3O4 on the surface of MCMSs. Through X–ray photoelectron spectroscopy analysis, Se(IV) can not only form inner–sphere complexes with MCMSs, but also be reduced to insoluble elemental selenium (Se0) by Fe3O4 which was oxidized and formed γ–Fe2O3. Moreover, the superparamagnetic MCMSs can be easily separated from solution by means of an external magnetic field. The high removal efficiency for Se(IV) and rapid separability of MCMSs made them promising materials for the application in the practice.

Deposition of Ag nanoparticles on carbon microspheres surface: Evaluation of structures, electrochemical and optical properties

A hybrid material of carbon microspheres (CMSs) with Ag decoration (Ag/CMSs) was developed. Poly (3-hexylthiophene):Ag/CMSs composite film was prepared by spin-coating. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, thermogravimetric analysis and cyclic voltammetry were employed to analyze the morphologies, structures, thermal properties and energy levels of Ag/CMSs. The optical property of the composite films was characterized by ultraviolet-visible spectrophotometry and fluorescent spectrometry. The results indicate that silver nanoparticles (Ag NPs, d = 10-20 nm) are distributed on the surface of CMSs. LUMO and HOMO energy levels of Ag/CMSs are -3.97 and -5.52 eV, below the vacuum energy level, respectively, indicating that it is feasible to use Ag/CMSs as an electron acceptor. Ag NPs are blended into the active layer to trigger localized surface plasmon resonance, and consequently enhance light harvesting. The coupling of surface plasmons and excitons increased the probability of exciton dissociation.

Multi-shelled α-Fe2O3 microspheres for high-rate supercapacitors

Hollow structured metal oxides are extensively studied in energy storage and conversion systems. In this work, we report the fabrication of multi-shelled Fe2O3 microspheres with nanospindles assembly on its exterior shell. The β-FeOOH precursor nanospindles were firstly grown on the surface of carbon microspheres to produce β-FeOOH@carbon composites, which were later converted into multi-shelled Fe2O3 microspheres by calcination in air. As electrode material for supercapacitors, the multi-shelled Fe2O3 microspheres exhibit high capacity and good rate capability. The electrode delivers the specific capacitances of 630 and 510 F g−1 at the current densities of 1 and 5 A g−1, respectively.

The structure of microencapsulated carbon microspheres and its flame retardancy in poly(ethylene terephthalate)

Abstract Carbon microspheres (CMSs) have been microencapsulated by poly(ethylene terephthalate) (PET). Microencapsulated carbon microspheres (MCMSs) flame retardant was obtained by in situ polymerization. Morphologies and structures of MCMSs have been studied by FESEM, TEM, FTIR and XRD. The results show that an organic shell layer of PET as capsule wall was coated on the surface of CMS with the thickness of about 50 nm. A series of PET blends were prepared by direct melt compounding with MCMSs as flame retardant. Compared with pure PET and CMSs/PET, the tensile strength of MCMSs/PET with 1 wt% MCMSs was increased because of good dispersion of MCMSs in the polymer PET matrix. Moreover, it was proved to be an effective flame retardant for MCMSs/PET as evidenced by increasing limiting oxygen index (LOI) value, which increasing from 21.0 for pristine PET to 27.3 for the PET with 1 wt% MCMSs. Meanwhile, UL-94 tests of the MCMSs/PET composites reached V-0 rating. Overall, this method endowed the MCMSs/PET composites with the good mechanical and flame-retardant properties, broadening their scope of application.

Synthesis and characterization of dibenzothiophene imprinted polymers on the surface of iniferter-modified carbon microspheres

Molecularly imprinted polymers (MIPs) on the surface of iniferter-modified carbon microspheres (CMSs) were synthesized by using dibenzothiophene (DBT) as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The influencing factors of monomer-grafting process were investigated. The characterizations of structure and morphology suggest that a thin layer of MIPs was grafted on the surface of CMSs under the optimized conditions. The adsorption results show MIPs-CMSs possessed higher binding capacity and selectivity than non-imprinted polymers on CMSs (NIPs-CMSs), and exhibited a good competitive adsorption capacity for DBT. The maximum adsorption capacity of MIPs-CMSs towards DBT reached 88.83 mg g−1. In addition, the adsorption of DBT on MIPs-CMSs follows Langergren pseudo second order model and Langmuir–Freundlich isotherm. Negative values of the Gibbs free energy, positive values of standard enthalpy and entropy reveal that the adsorption was a spontaneous, endothermic and entropically driven process during 288–318 K. From the regeneration experiments and adsorption results in the real oil, it is concluded that the MIPs-CMSs could be used in deep desulfurization of fuel oils.

Thermal Stability and Surface Chemistry Evolution of Oxidized Carbon Microspheres

The surface activity of carbon microspheres (CMSs) can be significantly improved through oxidation reaction. To explore the changes of CMSs in the thermal stability and surface chemical properties, oxidized-CMSs were obtained with a mixture of concentrated sulfuric and nitric acids as the oxidizing agent. The characterization of morphologies, microstructures and thermal properties shows that oxygen-containing functional groups were introduced onto the surface of CMSs. The parent CMSs showed 4.99wt% weight loss in nitrogen atmosphere, which was mainly due to the evolution of carbon monoxide CO; oxidized-CMSs exhibited 30.97wt% weight loss, which was attributed to the thermal degradation of the oxygen-containing functional groups in the form of H2O, CO2, CO and NO, as examined by mass spectrometry.

Selective removal of benzothiophene and dibenzothiophene from gasoline using double-template molecularly imprinted polymers on the surface of carbon microspheres

A novel double-template molecularly imprinted polymer (D-MIP) on the surface of carbon microspheres (CMSs), using benzothiophene (BT) and dibenzothiophene (DBT) as the template molecules, was prepared for the removal of benzothiophene sulfides from fuel gasoline. Field emission scanning electron microscopy and Fourier Transformation Infrared Spectrometry were used to characterize the morphology and structure of the D-MIP/CMSs. The adsorption behaviors of the D-MIP/CMSs including adsorption kinetics, isotherms, selectivity and regeneration were detected in detail by gas chromatography. The D-MIP/CMSs exhibited excellent selectivity toward BT and DBT with higher binding capacity in simulated gasoline compared to non-imprinted polymer (D-NIP/CMSs). The adsorption equilibrium of D-MIP/CMSs was achieved within 90min and the adsorption capacity reached 57.16 (BT) and 67.19mgg−1 (DBT), respectively. The pseudo-second order model and Langmuir–Freundlich isotherm described the adsorption of benzothiophene sulfides on the D-MIP/CMSs well. The D-MIP/CMSs could be used 10 times without significant loss in adsorption capacity. In addition, the D-MIP/CMSs exhibited good desulfurization effect in real oil. The D-MIP/CMSs provides a new material for deep desulfurization of fuel oils.

The Preparation of Carbon Microspheres Loading Silver Antimicrobial Agent and the Study of its Properties

Carbon microspheres (CMSs) were used as the carrier to prepare the Ag-loading CMSs (Ag/CMSs) antibacterial agent through the method of chemical adsorption. The morphologies and structures of modified CMSs were characterized by using the field emission Scanning Electron Microscope (SEM). The results showed that silver was absorbed on the surface of CMSs. The bacterial inhibition ring experiment showed that Ag/CMSs had good antibacterial activity against Staphylococcus aureus and Escherichia coli, meanwhile the diameters of the bacterial inhibition rings were 19 mm against Staphylococcus aureus and 21 mm against Escherichia coli, respectively.

Grafting molecularly imprinted poly(2-acrylamido-2-methylpropanesulfonic acid) onto the surface of carbon microspheres

Poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) was grafted on the surface of carbon microspheres (CMSs), which were modified in prior by a mixed acid (HNO3 and H2SO4) oxidation and 3-methacryloxypropyl trimethoxysilane silanization. Then, the molecularly imprinting polymerization was carried out towards the macromolecule PAMPS grafted on the surface of CMSs using dibenzothiophene (DBT) as template, ethylene dimethacrylate as cross-linking agent and (NH4)2S2O8 (APS) as initiator to prepare surface molecularly imprinted polymer (MIP-PAMPS/CMSs) for adsorbing DBT. The optimized conditions of grafting PAMPS, including AMPS dosage, APS content, reaction temperature and reaction time, were emphasized in this paper. The morphology of the samples was characterized by field emission scanning electron microscopy. The functional groups were analyzed qualitatively by Fourier transform infrared spectrometry. The grafting degree of PAMPS was investigated by thermogravimetry. The results show that the preferable AMPS dosage, APS content, reaction temperature and time were 5g, 0.15g, 70°C and 12h, respectively, for preparing PAMPS/CMSs composite on the basis of 1.0g of silanized-CMSs. The absorbing characteristic of MIP-PAMPS/CMSs toward DBT was studied preliminarily with dynamic adsorption. In the experiment of dynamic adsorption, MIP-PAMPS/CMSs and non-imprinted polymer (NIP-PAMPS/CMSs) were compared with respect to their rapid adsorption in 1mmol/L of DBT solution in n-hexane. When the first 1mL of 1mmol/L DBT solution was injected and flowed through a column packed with 0.1g of MIP-PAMPS/CMSs, the content of DBT reduced to 0.265mmol/L, that is, decreased significantly from 279 to 74ppm. When 3mL of DBT solution was flowed through the packed column, the adsorption of MIP-PAMPS/CMSs toward DBT reached saturation with the maximum adsorption amount of 1.38×10−2mmol/g and the overall adsorption efficiency of 46%, while NIP-PAMPS/CMSs adsorbed only 1.66×10−3mmol/g of DBT. It is suggested that the MIP-PAMPS/CMSs had much better adsorption property towards DBT than NIP-PAMPS/CMSs.