Template-free synthesis of MgO mesoporous nanofibers with superior adsorption for fluoride and Congo red

MgO mesoporous nanofibers were obtained by a template-free electrospinning method. The unique bumpy-structure was obtained on the surface of nanofibers that could enhance the surface area and provide more active sites for adsorption. The formation mechanism of the bumpy-structure has been investigated. The as-prepared MgO nanofibers with a high surface area of 194.17?m² g^?1 exhibited excellent adsorption capacities for fluoride of 237.49?mg?g^?1. Furthermore, the MgO nanofibers showed selective adsorption for different organic dyes and have superior adsorption capacity for Congo red (4802.27?mg?g^?1). The adsorption processes for both fluoride and Congo red were systematically investigated, which were found to follow the pseudo-second-order kinetic model. By comparison with the reported fabrication routes and adsorption capacities of mesoporous MgO, the synthesis process is simple, controllable and template-free, and the superior adsorption performance provided a potential adsorbent for the removal of fluoride and Congo red in wastewater treatment. The high surface area of the MgO mesoporous nanofibers might also promote its application in basic catalysis and other fields.     

Sacrificial template-directed synthesis of mesoporous manganese oxide architectures with superior performance for organic dye adsorption

Mesoporous MgO architectures were successfully synthesized by the direct thermal transformation of the sacrificial oxalate template. The as-prepared mesoporous architectures were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption-desorption techniques. The MgO architectures showed extraordinary adsorption capacity and rapid adsorption rate for removal of Congo red (CR) from water. The maximum adsorption capacity of the MgO architectures toward CR reached 689.7 mg g(-1), much higher than most of the previously reported hierarchical adsorbents. The CR removal process was found to obey the Langmuir adsorption model and its kinetics followed pseudo-second-order rate equation. The superior adsorption performance of the mesoporous MgO architectures could be attributed to the unique mesoporous structure, high specific surface area as well as strong electrostatic interaction.     

Surface modified mesoporous silica polymer nanocomposites for adsorption of dyes from aqueous solution

Functionalized mesoporous silica nanocomposites were synthesized via in situ radical polymerization of vinyl monomers (vinylcarbazole, vinyl imidazole and vinyl sulphonic acid) and characterized for adsorption of dyes from aqueous solution. Physicochemical characterization (PXRD, SEM, adsorption studies etc.) of the functionalized nanocomposites showed the presence of mesoporous nature of the nanocomposites. Different adsorption parameters such as adsorption weight, adsorption time, temperature, pH etc., were optimized for adsorption of dyes under environmental friendly conditions. The adsorption studies showed 96.8 and 80.49 % removal for cationic and anionic dyes respectively. Adsorption kinetics of the dyes on the functionalized nanocomposites can be well depicted theoretically by using pseudo-second-order kinetic model.     

Synthesis of bimodal mesoporous carbon nanospheres for methyl orange adsorption

Mesoporous materials with bimodal mesopores show advantages in adsorption, energy storage, and catalysis because such unique structures are beneficial to the mass transfer. Here, we describe the synthesis of bimodal mesoporous carbon nanospheres (BMCSs) by using phenolic resin as carbon precursor, triblock copolymer Pluronic F127 as the soft template, and mesoporous silica spheres as hard templates. The BMCSs with uniform spherical morphology, high specific surface area (1489 m² g^??1), large pore volume (0.92 cm³ g^??1), and bimodal mesoporous structure (3.8 and 6.8 nm) exhibit promising properties for adsorption of methyl orange (MO). The maximum adsorption capacity of the BMCSs is 5.5?×?10² ± 0.2?×?10² mg g^??1, which is higher than that of many adsorbents reported. The kinetics studies show a better fit of pseudo-second-order model. Meanwhile, fitting equilibrium data show that the Langmuir model is more suitable to describe the MO adsorption than Freundlich model.     

Selective silver ion adsorption onto mesoporous graphitic carbon nitride

A 3D cubic structure of mesoporous graphitic carbon nitride (3D-g-CN) was fabricated by nano casting using the mesoporous silica hard template KIT-6. The abundant intrinsic amine functionalities of 3D-g-CN were applied as a selective adsorbent for silver ions using the unique affinity of silver and amine functionalities. The large surface area of 3D-g-CN resulted in increased amine functionalities at the surface and enabled it to form complexes with silver ions. As a result, almost 400 mg/g of silver ion could be removed from 100 mM of initial solution at 293.15 K. The isotherm of silver ion adsorption onto 3D-g-CN was described by the Freundlich and Sips models and indicated heterogeneity of the adsorbent surface. Thermodynamic parameters determined from temperature dependent isotherms were verified by the endothermic silver ion adsorption process of 3D-g-CN. The adsorption capacity of silver ion on 3D-g-CN was maintained during several reuses without a significant decrease in capacity. Overall, the results indicate that 3D-g-CN has intrinsic amine functional groups with a large surface area and could therefore be utilized as an efficient selective adsorbent of silver ions for water purification.     

介孔炭的改性及其吸附脱硫选择性研究

用4种方法(浓硝酸、磷酸、双氧水、350℃焙烧)对介孔炭进行改性,并考察改性后的介孔炭在4种不同成分的模拟油中的吸附脱硫性能。对于仅含有芳烃或烯烃以及芳烃和烯烃均含有的模拟油,改性介孔炭的脱硫能力与未改性的介孔炭相比均有不同程度的下降。浓硝酸改性的介孔炭在仅含饱和烃的模拟油中的吸附脱硫性能优于其它方法;350℃焙烧处理的介孔炭与未改性的介孔炭在芳烃和烯烃均含有的模拟油中的吸附脱硫性能优于其它方法。考察了在350℃焙烧及浓硝酸处理后的介孔炭在不同温度下的脱附性能。结果表明,350℃焙烧处理的介孔炭在90℃下脱附率能达到66.91%。     

介孔炭的改性及其吸附脱硫选择性研究

用4种方法(浓硝酸、磷酸、双氧水、350℃焙烧)对介孔炭进行改性,并考察改性后的介孔炭在4种不同成分的模拟油中的吸附脱硫性能。对于仅含有芳烃或烯烃以及芳烃和烯烃均含有的模拟油,改性介孔炭的脱硫能力与未改性的介孔炭相比均有不同程度的下降。浓硝酸改性的介孔炭在仅含饱和烃的模拟油中的吸附脱硫性能优于其它方法;350℃焙烧处理的介孔炭与未改性的介孔炭在芳烃和烯烃均含有的模拟油中的吸附脱硫性能优于其它方法。考察了在350℃焙烧及浓硝酸处理后的介孔炭在不同温度下的脱附性能。结果表明,350℃焙烧处理的介孔炭在90℃下脱附率能达到66.91%。     

有序介孔碳和活性炭对阿莫西林的吸附研究

阿莫西林是废水中一类典型的药品与个人护理品类新型有机污染物,会对周围环境和人体健康造成潜在威胁。以蔗糖为碳源、以SBA-15为模板制备有序介孔碳（OMC）。采用动态吸附法研究其对阿莫西林的吸附行为,并与常规吸附材料商用活性炭（GAC）作对比。探讨了废水中阿莫西林的初始浓度、温度及流速对动态吸附的影响。结果表明：在同等条件下,OMC的吸附能力远强于GAC,以OMC为吸附剂可有效去除废水中的阿莫西林类新型有机污染物。     

Synthesis of benzxazine-based nitrogen-doped mesoporous carbon spheres for methyl orange dye adsorption

In this work, nitrogen-doped mesoporous carbon spheres (NMCS) were synthesized through a hard template method by using benzoxazine resin as precursor and ordered mesoporous silica spheres as template. The obtained N-doped mesoporous carbons were amorphous spherical nanoparticles with worm-like mesoporous channels and possessed high surface area of 789 m²/g, large pore volume of 0.49 cm³/g and high nitrogen content of 3.50 wt.%. The adsorption capacity of methyl orange (MO) by NMCS could attain 352.1 mg/g at an optimal condition, while the adsorption capacity of MO by non-doped mesoporous carbon spheres (MCS) was 251.9 mg/g at the same condition. The adsorption process fitted the pseudo-second-order kinetic model and the Langmuir isotherm well. Thermodynamic analysis indicated that the removal of MO by NMCS was spontaneous, endothermic and feasible process. In addition, the adsorption capacity of regenerated adsorbent was 89.04% of the initial level after four regeneration cycles.     

Synthesis of an ordered mesoporous carbon with graphitic characteristics and its application for dye adsorption

An ordered mesoporous carbon (OMC) was prepared by a chemical vapor deposition technique using liquid petroleum gas (LPG) as the carbon source. During synthesis, LPG was effectively adsorbed in the ordered mesopores of SBA-15 silica and converted to a graphitic carbon at 800 °C. X-ray diffraction and nitrogen adsorption/desorption data and high-resolution transmission electron microscopy (HRTEM) of the OMC confirmed its ordered mesoporous structure. The OMC was utilized as an adsorbent in the removal of dyes from aqueous solution. A commercial powder activated carbon (AC) was also investigated to obtain comparative data. The efficiency of the OMC for dye adsorption was tested using acidic dye acid orange 8 (AO8) and basic dyes methylene blue (MB) and rhodamine B (RB). The results show that adsorption was affected by the molecular size of the dye, the textural properties of carbon adsorbent and surface-dye interactions. The adsorption capacities of the OMC for acid orange 8 (AO8), methylene blue (MB) and rhodamine B (RB) were determined to be 222, 833, and 233 mg/g, respectively. The adsorption capacities of the AC for AO8, MB, and RB were determined to be 141, 313, and 185 mg/g, respectively. The OMC demonstrated to be an excellent adsorbent for the removal of MB from wastewater.     

Highly-efficient adsorption behavior of mesoporous Co-HDIPT toward both anionic and cationic organic dyes

Journal of Porous Materials - Metal–organic frameworks (MOFs) exhibit the prominent advantages in the efficient removal of organic dyes owing to their diverse topology structure, adjustable...     

中孔炭对葡萄叶中白藜芦醇静态吸附性能的研究

本研究以中孔炭为吸附材料,吸附葡萄叶中的白藜芦醇。通过静态吸附实验,研究其吸附机理。结果表明,Langmuir和Freundlich方程均可以较好地表述中孔炭对白藜芦醇的吸附;中孔炭对白藜芦醇的吸附符合二级动力学模型(R²>0.99),外扩散和粒子内扩散共同控制吸附过程;中孔炭对白藜芦醇的吸附是自发进行的吸热反应(ΔH<0,ΔG<0),且混乱度增加(ΔS>0)。研究为中孔炭在白藜芦醇的纯化应用方面提供了理论依据,以期为吸附法纯化白藜芦醇提供新的吸附剂。     

中孔炭对葡萄叶中白藜芦醇静态吸附性能的研究

本研究以中孔炭为吸附材料,吸附葡萄叶中的白藜芦醇。通过静态吸附实验,研究其吸附机理。结果表明,Langmuir和Freundlich方程均可以较好地表述中孔炭对白藜芦醇的吸附;中孔炭对白藜芦醇的吸附符合二级动力学模型(R~2>0.99),外扩散和粒子内扩散共同控制吸附过程;中孔炭对白藜芦醇的吸附是自发进行的吸热反应(ΔH<0,ΔG<0),且混乱度增加(ΔS>0)。研究为中孔炭在白藜芦醇的纯化应用方面提供了理论依据,以期为吸附法纯化白藜芦醇提供新的吸附剂。     

Synthesis of mesoporous carbon and its adsorption property to biomolecules

Mesoporous carbon (MC) with high surface area and large pore volume was synthesized using mesophase pitch as a carbon precursor and nanosized MgO as an additive. The maximum surface area, largest pore volume and highest mesoporous ratio of as-prepared MC were up to 1400 m²/g, 2.8 cm³/g and 89%, respectively. The mesoporous structures (3–40 nm) of MC were directly observed under SEM and TEM. The adsorption capacity and adsorption rate of MC to vitamin B₁₂ (VB), chicken egg white albumin (CEWA) and bovine serum albumin (BSA) were proportional to the mesopore volume and average pore size. MC (PM4-OC) exhibited the maximum adsorption capacity to the typical biomolecules, 486, 140 and 176 mg/g for VB, CEWA and BSA, respectively. In contrast, Maxsorbs (commercial activated carbons) with a surprising surface area gave a very low adsorption to such biomolecules. The research indicates that MC may be potential in the selective adsorption and separation of biomolecules, based on a molecule sieve effect.     

新型介孔碳的制备及对罗丹明B的吸附动力学研究

采用SBA-15氧化硅分子筛为模板制备有序介孔碳CMK-3,研究了CMK-3作为吸附剂在水溶液中对罗丹明B的吸附作用,同时研究了初始浓度、pH和温度对吸附的影响.结果表明随着初始浓度的增大、pH增加和温度升高,吸附量增大,但是在较低的pH下,吸附量增加的较小,当pH较高时,吸附量增加的较多.分别采用拟一级反应和拟二级反应模型考察了吸附动力学,并计算了这些动力学模型的速率常数.拟二级反应模型和实验数据之间有较好的相关性.     

活性炭纤维对水中酸性染料的吸附研究

采用ZnCl2活化稻草秸秆炭化得到的活性炭纤维吸附酸性品红,考察了投加量、pH、吸附时间、初始浓度及温度对吸附性能的影响,并对等温吸附特征、吸附热力学和动力学进行系统研究。结果表明:投加量为0.1 g,pH=1时,活性炭纤维对酸性品红具有很好的吸附效果,吸附在8 h后达到平衡。该吸附过程符合Langmuir及Freundlich等温吸附模型和准二级动力学方程,其反应的吉布斯自由能ΔG<0,为自发反应。     

Synthesis and characterization of mesoporous graphite carbon,and adsorption performance for benzene

In this paper, graphite carbon with a mesoporous structure was synthesized using the template–catalysis procedure with hydrated metal oxide nanoparticle as template and catalyst, phenol and formaldehyde as carbon source. XRD, Raman, BET and TEM analyses were performed to study the effluence of synthetic conditions on the structure of samples. The adsorption performances for benzene vapor were evaluated. The results show that CCo and CFe samples have mesoporous graphitized carbon structures. The molar amount of template to carbon source significantly affects the specific surface area, pore structure and adsorption–desorption performance. The specific surface area of CCo-1, with the best graphite structure, was 287.638 m²/g, the pore size was 19.075 nm, and the adsorption capacity for benzene vapor was 19.615 mmol/g. The synergistic effect between the cobalt element and graphite carbons affects the adsorption capacity of CCo-3, which was 34.643 mmol/g. However, the desorption efficiency was only 89 %, and the adsorption performance of CCo-3 material was degraded greatly after three times run.     

A rosette like carbon structure controlled through ammoniation for superior adsorption of cationic brilliant green dye

Journal of Porous Materials - This paper investigates the influence of the structure, composition, pore size distribution and morphology of three carbon materials obtained from the explosion of...     

Simplified model for the equilibrium adsorption of dyes from mixtures using activated carbon

Adsorption isotherms have been determined experimentally for the single-component adsorption of three dyes, namely, Basic Red 22, Basic Yellow 21, and Basic Blue 69 onto carbon. In addition, the three possible bisolute isotherms and the one trisolute isotherm for these three dyes were determined. In each case the Langmuir, Freundlich and Jossens isotherm constants were determined and the Langmuir data were then used to correlate and predict the multicomponent isotherm data from single-component data in a simplified manner.     

NO2 adsorption at ambient temperature on urea-modified ordered mesoporous carbon

A soft-templated ordered mesoporous carbon was synthesized, impregnated with urea and pyrolyzed at 500 and 800 °C. The samples obtained were tested as NO₂ adsorbents. Their structural properties and surface chemistry, before and after NO₂ exposure, were investigated using nitrogen adsorption, TEM, potentiometric titration and thermal analysis. Results showed that the ordered mesoporous structure remains stable throughout the treatment applied and exposure to NO₂. Even though the initial carbon exhibited a high NO₂ adsorption capacity, the incorporation of nitrogen groups to the carbon surface, resulted in the further improvement of the performance after heat treatment. The mechanism of reactive adsorption was found to be significantly affected by surface chemistry of mesoporous carbons.