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Volume 46, Issue 9 , September 2011 , Pages 1424-1430
2021, Journal of Hazardous Materials
2021, Journal of Hazardous Materials
Materials Letters, Volume 167, 2016, pp. 58-60
Materials Letters, Volume 128, 2014, pp. 19-22
Materials Chemistry and Physics, Volume 178, 2016, pp. 57-64
Microporous and Mesoporous Materials, Volume 211, 2015, pp. 162-173
Electrochimica Acta, Volume 166, 2015, pp. 310-319
Microporous and Mesoporous Materials, Volume 198, 2014, pp. 175-184
Copyright © 2011 Elsevier Ltd. All rights reserved.
Highly ordered mesoporous carbon with large accessible pores (OMC-P) was prepared by using laboratory-made poly(ethylene oxide)-b-polystyrene diblock copolymer as template via the evaporation-induced self-assembly method. The OMC-P was first used as adsorbent for removal of Cr(VI) ion from aqueous solution. Adsorption behavior was studied as a function of time, concentration of adsorbate, temperature, and pH. The kinetics of adsorption of Cr(VI) ion onto OMC-P is well fit to the pseudo-second order model. The Cr(VI) ion adsorption is favored at lower temperatures and at initial acid pH values in the equilibrium. The Freundlich and the Langmuir isotherm fit the equilibrium data satisfactorily. The influence of porosity on equilibrium adsorption capacity was investigated on three types of carbon materials, namely, OMC-P, ordered mesoporous carbon templated from amphiphilic triblock copolymer F127 (OMC-F) and commercial activated carbon (AC). The prepared OMC-P exhibits much higher adsorption performance than the other two carbons.
We report the successful synthesis of ordered large-pore mesoporous carbon with uniformly penetrating channels by the evaporation induced self-assembly process. The ordered large-pore mesoporous carbon (OMC-P) is first reported here as adsorbent for adsorption of Cr(VI) ion from aqueous solution. Download : Download full-size image
► Ordered large-pore mesoporous carbon was prepared by using PEO-b-PS diblock copolymer . ► OMC-P was first used as adsorbent for removal of Cr(VI) ion from aqueous solution. ► Ordered large-pore mesoporous carbon is effective for the removal of Cr(VI).
Cr(VI) contamination generated from various industries, such as electroplating, leather tanning, mining, steel making, and pigments, has a significant impact on human health and other living organisms in the environment [1]. A wide range of physical and chemical processes is available for the removal of Cr(VI) ion from water, such as electrochemical precipitation [2], ultrafiltration [3], ion exchange [4] and adsorption [5]. Among them, the adsorption method is very efficient for Cr(VI) ion removal due to its clean operation and complete removal of heavy metal ions even from dilute solutions [6]. Activated carbon (AC) is one of the most widely used adsorbents [7], [8]. However, AC has broad pore size distributions, ranging from micropores to macropores. This phenomenon may lead to the restricted practical applications of AC [9]. In recent investigations [10], [11], [12], ordered mesoporous carbons are proposed elsewhere for desirable adsorption of heavy metal ions.
Since the discovery [13], [14], [15], ordered mesoporous carbons have attracted great interest due to its unique physical and chemical proprieties, and they have shown great potentials for diverse applications in adsorption [16], catalysis [17], [18], and electrodes [19], [20], [21]. Ordered mesoporous carbons are traditionally fabricated by the nanocasting technique [13], [14], [15]. The procedure has been engaged in infiltration of an appropriate carbon precursor into the mesopores of the silica template followed by thermal polymerization, carbonization, and subsequent removal of the silica framework with HF or NaOH solution [22]. Recently, several groups developed the direct soft template synthesis method for ordered mesoporous carbons from the self-assembly of amphiphilic block copolymers and phenolic resins [23], [24], [25]. This innovative soft-templating synthesis procedure has great advantages over the complicated hard-templating procedures in that it is simple, cost effective, and suitable for large-scale synthesis. This process makes it possible to conveniently synthesize mesoporous carbons with pore sizes of 3–7 nm and various pore structures on large scale by using Pluronic block copolymers as templates, but also stimulates great interest in ordered mesoporous carbons with pore size ranging from 10–50 nm, which are appealing for applications involving large size guest objects, such as low-abundance protein enrichment, enzyme immobilization, and virus separation. However, large-pore ordered mesoporous carbons are hardly accessible by using hard templating approach or the soft-templating method based on Pluronic copolymers due to the limitation of the templates’ molecular weight [26]. More recently, high-molecular-weight amphiphilic block copolymers have been successfully demonstrated for templating synthesis of ordered mesoporous carbons with large pore sizes and tunable porous structure through EISA approach [27], [28], [29], [30]. But because of the difficulties for synthesis, there is no report on the application of such large-pore ordered mesoporous carbon so far.
In this paper, large-pore ordered mesoporous carbon (OMC-P) was prepared via soft-template approach and utilized in Cr(VI) absorption. To the best of our knowledge, the OMC-P was first reported here as adsorbent for adsorption of Cr(VI) ion from aqueous solution. By comparing with the ordered mesoporous carbon templated from amphiphilic triblock copolymer F127 (OMC-F), OMC-P delivers the higher adsorption capacity on Cr(VI) from 128.21 to 189.39 mg g −1 , indicating its significantly favorable remarkable potential for adsorption of Cr(VI). Both kinds of ordered mesoporous carbon, which are derived from the same phenolic resins precursors and have the similar structure but remarkably different pore sizes, show about twice adsorption capacities for Cr(VI) ion in comparison with AC (72.31 mg g −1 ).
Ordered mesoporous carbon with large accessible pores (denoted as OMC-P), using laboratory-made high-molecular-weight diblock copolymer PEO-b-PS ( M w = 23,000, PEO 125 PS 168 ) as template derived from the direct transformation of low-molecular-weight phenol–formaldehyde resol, was employed as the adsorbent for Cr(VI) removal.
The diblock copolymer poly(ethylene oxide)-b-polystyrene (PEO-b-PS) template was prepared by a simple method of atom transfer radical polymerization (ATRP) (Fig. S1, Supporting
N 2 sorption isotherms of OMC-P (inset of Fig. 1a) behave like representative type IV curves with a sharp capillary condensation step in the relative pressure range of 0.85–0.95. It indicates the generation of mesopores with a large uniform size. A very large H 2 -type hysteresis loop with delayed capillary evaporation located at a relative pressure of about 0.5 is observed in the isotherms, implying caged mesopores with a window size smaller than 5.0 nm [27]. On the basis of the Broekoff–de Boer
We have developed the evaporation induced self-assembly process for large-scale synthesis of ordered large-pore mesoporous carbon with uniformly penetrating channels. The obtained ordered large-pore mesoporous carbon possesses uniform large-pore size and well-ordered channels and is used as adsorbent for removal of Cr(VI) ion from aqueous solution. The adsorption results show that obtained ordered large-pore mesoporous carbon is an effective adsorbent for the removal of Cr(VI) from aqueous
The authors appreciate the financial support of the National Natural Science Foundation ( 50871053 ) and the Aeronautical Science Foundation of China ( 2007ZF52061 ).
Phosphate functionalized graphene oxide (PGO) was successfully prepared by Arbuzov reaction and employed for adsorption of resorcinol from an aqueous phase. The phosphate functional groups were successfully incorporated onto the PGO surface by the formation of P–C bonds as identified by the analysis of FTIR and XPS spectra. The evaluation of adsorption capacity of resorcinol onto PGO exhibited significant improvement of resorcinol removal, achieving an adsorption capacity of 50.25 mg/g in the pH range of 4–7 which was 15 times higher than pristine graphene oxide. The addition of 2.4 M and 5 M NaCl in the adsorption system significantly increased the adsorption capacity towards resorcinol from 50.25 mg/g to 82.10 mg/g and 128.10 mg/g, respectively. Based on kinetics and adsorption isotherm studies, Pseudo-First-Order and Langmuir model are the best model to describe the adsorption process indicating that the adsorption is dominantly controlled by physisorption. The thermodynamic analysis suggested that the adsorption process was the favorable, spontaneous, and endothermic process. Besides, the interplay of hydrogen bonding and π-π interactions is proposed to be the governing physisorption mechanism. The outstanding reusability and better adsorption performance make PGO a promising adsorbent for environmental remediation of resorcinol.
Contamination of water bodies by potentially toxic elements and organic pollutants has aroused extensive concerns worldwide. Thus it is significant to develop effective adsorbents for removing these contaminants. As a new member of carbonaceous material families (activated carbon, biochar, and graphene), ordered mesoporous carbon (OMC) with larger specific surface area, ordered pore structure, and higher pore volume are being evaluated for their use in contaminant removal. In this paper, modification techniques of OMC were systematically reviewed for the first time. These include nonmetallic doping modification (nitrogen, sulfur, and boron) and the impregnation of nano-metals and metal oxides (iron, copper, cobalt, nickel, magnesium, and rare earth element). Reaction conditions (solution pH, reaction temperature, sorbent dosage, and contact time) are of critical importance for the removal performance of contaminants onto OMC. In addition, the pristine and modified OMC have been investigated for the removal of a range of contaminants, including cationic/anionic toxic elements and organic contaminants (synthetic dye, phenol, and others), and involving different and specific mechanisms of interaction with contaminants. The future research directions of the application of pristine and modified OMC were proposed. Overall, this review can provide sights into the modification techniques of OMC for removal of environmental contaminants.
It is challenging to efficiently remove arsenate (As(Ⅴ)) and chromate (Cr(Ⅵ)) simultaneously. Herein, ordered mesoporous carbon (OMC) was fabricated with averaged pore diameter of 6.5 nm and surface area of 997 m 2 g −1 . Zerovalent iron (ZVI) impregnation reduced surface area of ZVI/OMC (432 m 2 g −1 ) and increased I D /I G ratio by 13%. Maximal Cr(Ⅵ) and As(Ⅴ) sorption capacities at pH 3 were 0.66 and 0.019 mmol g −1 by OMC, and 0.71 and 0.39 mmol g −1 by ZVI/OMC, respectively. Reduction accounted for over 55% for Cr(Ⅵ) and As(Ⅴ) removal followed by complexation and precipitation. Better ZVI/OMC performance was ascribed to higher electron transfer rate and lower electrical resistance than OMC as per electrochemical analysis. Upon Cr(Ⅵ) introduction, As(Ⅴ) removal increased to 0.28 mmol g −1 by OMC, but decreased to 0.16 mmol g −1 by ZVI/OMC. OMC could preferably reduce CrO 4 2− to Cr 3+ by hydroxyl group, which enhanced its zeta potential facilitating As(Ⅴ) sorption. Regarding ZVI/OMC, Fe 0 and Fe oxide in ZVI/OMC exhibited better affinity to As(Ⅴ), but the competition for the similar active sites resulted in compromised As(Ⅴ) and Cr(Ⅵ) removal. Thus, the novel OMC is advantageous for removal of binary As(Ⅴ) and Cr(Ⅵ), but ZVI/OMC is robust to detoxify single heavy metal.
An ideal adsorbent should possess the ability of being easily fabricated, cheap to produce, and have a high adsorptive capacity for adsorbates. Ordered mesoporous carbon (OMC), a moderately new member of the carbonaceous family of adsorbents, has arisen as a potential adsorbent because of its distinct features such as high BET surface area, large pore size and porosity volume, tunable surface chemistry and thermo-mechanical stability. In this review paper, we have presented a systematic documentation of all the research efforts on OMC preparation, modification, characterization, and environmental application for pollutant removal. The subsequent characterizations of OMC employing different techniques, such as, N 2 Adsorption-Desorption Isotherm, scanning electron microscope (SEM) and transmission electron microscope (TEM) images, X-ray diffraction (XRD) pattern, fourier transform infrared spectroscopy (FTIR) and X-ray photon spectroscopy (XPS) spectra, are summarized. Furthermore, we have compared the adsorption performance of different modified OMCs towards different inorganic pollutants, such as heavy metals, and various organic pollutants categorically, such as dyes, phenols and their derivatives, volatile organic compounds (VOCs), alkaloids, nitrogen containing organic compounds, and vitamins. Future research directions on functionalized OMC for the adsorptive removal of emerging pollutants and other environmental applications are also provided.
%), within-interconnected hollow cavity/mesoporous shells and especially interconnected microstructure of internal cavities, the hierarchical nanostructured NMHCSs are expected to be an improved mass transport and a higher selectivity which will have a good application prospect for the electrode materials of the supercapacitors. In addition, small size of NMHCSs (especially less than 50 nm) which possess the interconnected microstructure of internal cavities also can be effectively applied for adsorption, catalysis, biomedicine and energy storage/conversion devices [25–35]. The adsorption-desorption of electrolyte ions at the interface of electrolyte/electrode will ultimately determine the energy storage efficiency of carbon-based supercapacitors.
A series of N-doped porous carbon materials with open interconnected mesoporous shells and various mesoscopic morphology were synthesized by using the cationic Gemini surfactant pentane-1,5-bis(dimethylcetyl ammonium bromide) as the soft template through a sol-gel method and the mechanism of interfacial reaction was explored. The controllable morphological structure (particle size, shell thickness and interconnected structure of internal cavities in carbon nanospheres) can be easily achieved by simply adjusting the volume of ethanol and the amount of cationic Gemini surfactant. The synthesized N-doped mesoporous hollow carbon spheres (NMHCSs) exhibit the characteristics of small and tunable particle size (30–140 nm), ultrahigh surface area (1215–1517 cm 2 g −1 ) and large pore volume (1.12–3.22 cm 3 g −1 ), open interconnected hierarchical mesoporous (5–20 nm), high proportion doping of heteroatoms N (4.16–6.74 at.%) and O (6.17–8.68 at.%). The representative NMHCSs as electrical double layer capacitors electrodes in 6 M KOH electrolyte display an excellent electrochemical specific capacitance (240 F g −1 at 0.2 A g −1 ), superb capacitance retention (161 F g −1 at 20 A g −1 ), and excellent cycle stability (92% capacitance retention at 10 A g −1 after 5000 cycles). This research develops a simple synthesis strategy for a series of N-enriched carbon materials which exhibit promising application prospects for high-performance supercapacitors.
For GS-C, which is microporous, plateaued capacity for Ce > 60 mg/L confirms monolayer coverage of Cr(VI) on the carbon surface (Demiral et al., 2008). In contrast, the mesoporous samples have penetrating channels and added pore volume that is accessible to Cr(VI) when the concentration gradient is high (Chen et al., 2011). The highest Cr(VI) removal for Fe/GS-C and Fe/GP-C are 42% and 57% more than their carbon control counterparts, due to added mesopore volume.
Rapid increases in biodiesel use results in a surplus of its production by-product, glycerol, exceeding demand by traditional applications. In this study, Fe/C composites are prepared from glycerol-based precursors that include a dissolved iron salt via one-pot, two-stage pyrolysis. The first heating stage dehydrates, polymerizes, and carbonizes glycerol via acid-assisted pyrolysis while homogeneously dispersing a precipitated iron salt throughout the generated carbon matrix. The second stage develops porosity in the carbon support while reducing impregnated iron nanoparticles. Carbon supports with tailored physiochemical properties are generated by varying the dehydration acid (H 2 SO 4 or H 3 PO 4 ). Fe/C samples are predominantly mesoporous, with specific surface areas up to 560 m 2 /g and bulk iron contents up to 8.9 wt%, primarily as partially reduced Fe 3 O 4 . Cr(VI) removal follows the Freundlich model, reaching 107 mg/g at pH = 5. Mesoporous Fe/C composites are magnetic, allowing collection for reuse. After 4 use/recovery/reuse cycles, performance drops by < 25% when the products are applied in an actual wastewater system. Overall, the magnetic mesoporous Fe/C composite materials are straightforward to produce from waste glycerol and exhibit potential for environmental application in aqueous systems.
Improvement of curing performance of unsaturated polyester (UPR) by multi-walled carbon nanotubes (MWCNT) is essential for industrial application of MWCNT reinforced UPR nanocomposites. For this purpose, hyper branched polyester coated MWCNT (HBPCNT) has been prepared by solvent evaporation technique, and HBPCNT loaded UPR nanosuspension has been cured and investigated with differential scanning calorimetric method. Structures and morphologies of pristine MWCNTs and HPBCNTs have also been investigated. Significant differences in the natures of these two types of CNTs are observed. HBPCNT remarkably reduces the curing temperature by 13 °C during crosslinking in HBPCNT-UPR nano-suspension, thereby acting as a potential anti-scavenger for curing process.
Poly(methyl methacrylate)-functionalized graphene/polyurethane (MG–PU) dielectric elastomer composites were synthesized. MG was prepared by atom transfer radical polymerization (ATRP) and used as conducting filler. The microstructure of MG and MG–PU was characterized by SEM, TEM and XRD. The thermal degradation, mechanical, dielectric and electromechanical properties were investigated. The three-dimensional (3D) electric field induced displacement and strain of dielectric elastomer surface was observed and measured for the first time. Comparing with pure PU elastomer, the dielectric properties and electric field induced strain performance of MG–PU dielectric elastomer composites were significantly improved. The 1.50 wt% MG–PU film had high relative permittivity and electric field induced strain of 28.21 and 32.8%, respectively.
In this study, the adsorption of heavy metal ions onto ordered mesoporous carbon CMK-3 was investigated. CMK-3 has been synthesized using SBA-15 as the hard template and then directly amino-functionalized by the treatment with 3-aminopropyltrimethoxysilane (APTMS) without the need of oxidation before. The thus obtained modified mesoporous carbon has been characterized by nitrogen sorption, X-ray diffraction and infrared spectroscopy. Its adsorption efficiency for the removal of Cu 2+ and Pb 2+ from aqueous solutions was tested. The effects of contact time, pH and initial metal ions concentration were investigated as well. The adsorption capacities were very high (3.5 mmol g −1 and 8.6 mmol g −1 for Pb 2+ and Cu 2+ respectively). These values depend largely on the speciation of metal ions as a function of pH. The selectivity was also dependent on the nature of metal ions rather than the adsorbent used. The mechanism of adsorption is complex where several types o
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