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.     

A wormhole-structured mesoporous carbon with superior adsorption for dyes

A series of large-pore mesoporous carbon materials with a three-dimensional wormhole framework structure were synthesized by nanocasting using mesoporous silica as a hard template. Samples of hard-template mesoporous silica with pore diameters from 3.08 to 6.43 nm, pore volumes from 0.59 to 1.02 cm³ g⁻¹ and surface areas from 832 to 579 m² g⁻¹ were prepared from tetraethyl orthosilicate as the silica source and ionic liquid 1-butyl-3-methylimidazolium bromide as structure-directing agent through hydrothermal treatment at different temperatures (110–150 °C) followed by calcining at 550 °C. Subsequently, carbon materials with large pore diameters (2.76–6.70 nm), pore volumes (0.74–2.10 cm³ g⁻¹) and high surface areas (1074–1276 m² g⁻¹) were synthesized using the various mesoporous silicas synthesized at the different hydrothermal temperatures as a hard-template. The carbon material obtained at a hydrothermal temperature of 150 °C possesses outstanding adsorbility for amaranth and methylene blue dyes.     

新型介孔有机聚合物对氢气存储和染料快速吸附研究

采用二甲氧基甲烷对四苯基硼酸钠进行Friedel-Craft烷基化,得到了一种具有阴离子骨架的介孔材料MPTB-1。借助气体吸附仪和紫外分光光度计对该材料氢气存储性能和常见有机染料分子的吸附性能进行研究。结果表明,材料孔径分布在5.3 nm附近,属于介孔材料;在分压0.1 MPa时可以吸附1.19%(质量分数)的氢气;该材料对阳离子染料罗丹明B具有较高的吸附效率,对水中染料去除率30 min可达99%以上;MPTB-1对罗丹明B的吸附等温线符合Langmuir模型,吸附动力学符合准二级动力学模型。表明材料对罗丹明B的吸附为均匀的单分子层吸附,而且两者之间存在化学吸附作用。     

Magnetic mesoporous iron oxide/silica composite aerogels with high adsorption ability for organic pollutant removal

In this paper, a kind of magnetic mesoporous iron oxide/silica composite aerogels with high adsorption ability is prepared by ambient pressure drying method. The results indicate that the obtained magnetic aerogels with Fe/Si (molar ratio) >0.91 % have higher specific surface area with 310.8–411.0 m² g^?1 and pore volume with 0.85–1.12 cm³ g^?1. The adsorption test indicates that the obtained magnetic aerogels showed prominent adsorption capability with the adsorption rate for Rhodamine B in aqueous solution could attain to 95.8 % within 80 min. Moreover, all the composite aerogels exhibited good magnetic properties and could be easily separated from the water after adsorption.     

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.     

介孔及介观结构材料掺杂有机染料的研究进展

从材料制备方法的角度出发,对近年来介孔及介观结构材料掺杂有机染料的光学性能研究进行了综述,比较分析了各种制备方法的优缺点,对其在光学各领域的应用前景作了展望。     

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.     

介孔氧化锰对甲醛的低温催化氧化

采用硬模板法合成了介孔氧化锰纳米材料,考察了甲醛浓度对甲醛的催化氧化活性的影响。通过X射线衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)等分析手段对合成的介孔材料进行了表征。结果显示,所合成的氧化锰具有很好的有序三维介孔结构,对甲醛具有优异的催化性能。甲醛的初始浓度对催化剂的活性有很大的影响,随着初始浓度的降低,催化剂活性逐渐提高。当甲醛的初始浓度为30 mg/L时,氧化锰催化剂在40℃时即可将甲醛完全降解。对于非贵金属型甲醛降解催化剂,此温度属于较低的。氧化锰优异的催化活性可能与其有序的介孔结构有很大的关系。     

介孔氧化锰对甲醛的低温催化氧化

采用硬模板法合成了介孔氧化锰纳米材料,考察了甲醛浓度对甲醛的催化氧化活性的影响。通过X射线衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)等分析手段对合成的介孔材料进行了表征。结果显示,所合成的氧化锰具有很好的有序三维介孔结构,对甲醛具有优异的催化性能。甲醛的初始浓度对催化剂的活性有很大的影响,随着初始浓度的降低,催化剂活性逐渐提高。当甲醛的初始浓度为30 mg/L时,氧化锰催化剂在40℃时即可将甲醛完全降解。对于非贵金属型甲醛降解催化剂,此温度属于较低的。氧化锰优异的催化活性可能与其有序的介孔结构有很大的关系。     

Direct synthesis and superior catalytic performance of V-containing SBA-15 mesoporous materials for oxidative dehydrogenation of propane

V-containing SBA-15 mesoporous materials have been directly synthesized in an acidic and peroxidic medium. Compared to V/SBA-15 and V/SiO₂ samples prepared by impregnation method, the materials thus synthesized show larger surface areas, higher dispersion and reducibility of VO _x species, and superior catalytic performance for oxidative dehydrogenation of propane.     

Hydrothermal synthesis of mesoporous carbons for adsorption of two alkaloids

Two mesoporous carbons were synthesized via a hydrothermal treatment approach, characterized and evaluated for adsorption properties of berberine hydrochloride and matrine from water. The mesoporous carbons have BET specific surface areas of 1568.1 and 769.3 m²/g, pore volumes of 1.44 and 0.89 cm³/g, average pore diameters of 3.75 and 8.22 nm, and few O-containing functional groups on the surfaces. Both the mesoporous carbon adsorbents can effectively adsorb berberine hydrochloride and matrine from aqueous solutions, the higher equilibrium adsorption capacities of berberine hydrochloride and matrine at 298 K are 385, and 275 mg/g at 0.10 mg/mL, respectively. Adsorption enthalpy, entropy and free energy of berberine hydrochloride and matrine on the selected mesoporous carbon (with higher BET specific surface area and pore volume) were calculated. The adsorption of berberine hydrochloride and matrine on the selected carbon sample is fast at 298 K, 95% of the adsorption equilibrium could be achieved within 180 and 120 min, respectively. The dynamic adsorption capacities on the selected adsorbent are calculated to be 343.1 and 383.4 mg/g for berberine hydrochloride and matrine, respectively; and 70.8% of the adsorbed berberine hydrochloride and 79.2% of the adsorbed matrine could be desorbed by a 70% alcohol solution. These results provide a reference to the large-scale industrial production and application of mesoporous carbons as potential adsorbents in purification of alkaloids from herbal plant extracts.     

Preparation of manganese monoxide@reduced graphene oxide nanocomposites with superior electrochemical performances for lithium-ion batteries

Manganese monoxide (MnO) nanowire@reduced graphene oxide (rGO) nanocomposites are synthesized using a simple hydrothermal method combined with a calcination process. The structural and morphological characterization of the composites indicates that the MnO nanowires homogeneously anchor on both sides of the cross-linked rGO. The nanocomposites exhibit a high surface area of 126.5?m² g^?1. When employed as an anode material for lithium-ion batteries, the nanocomposites exhibit a reversible capacity of 1195 mAh g^?1 at a current density of 0.1?A?g^?1, with a high charge-discharge efficiency of 99.2% after 150 cycles. The three-dimensional architecture of the present materials exhibits high porosity and electron conductivity, significantly shortening the diffusion path of lithium ions and accelerating their reaction with the electrolyte, which greatly improves the lithium-ion storage properties. These excellent electrochemical performances make the composite a promising electrode material for lithium-ion batteries.     

介孔分子筛在挥发性有机化合物吸附中的研究进展

挥发性有机化合物(VOCs)是破坏生态环境质量的重要污染物,近年来发现介孔分子筛对VOCs有较好的吸附效果.综述了近年来介孔分子筛在VOCs吸附中的研究进展,详细讨论了VOCs在介孔分子筛吸附剂上的吸附过程,并对以后介孔分子筛吸附剂的研究提出了建议.     

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.     

介孔锰氧复合物的表面活性剂模板合成与孔结构分析

锰氧复合物以其在电化学与催化等领域的众多应用而得到研究者的广泛关注。采用非离子表面活性剂（脂肪醇聚氧乙烯醚,AEO9）模板与溶胶凝胶反应相结合,制备了平均孔径在5.0nm、BE比表面积为387m^2/g和热稳定性良好的介孔锰氧复合物。高分辨率透射电镜的直接观察发现该材料由大量有序排列的层状微晶构成,这不同于文献中类似溶胶－凝胶方法合成所得的非晶态氧化锰材料的结果。同时根据N2吸脱附等温线类型与物理吸附理论对材料的孔结构进行了简单解释。采用该方法制备的介孔材料总孔体积与合成中表面活性剂用量呈线性关系,表明AEO9在材料制备中是起模板构筑作用的。     

Effect of organic groups on hydrogen adsorption properties of periodic mesoporous organosilicas

We investigate the hydrogen adsorption properties of periodic mesoporous organosilicas (PMOs) and focus, in particular, on how these properties are affected by diverse organic groups embedded in the walls. PMOs with π electrons on the pore surface adsorb more hydrogen molecules per unit area and have a higher isosteric heat of hydrogen adsorption (Q_st). The number of adsorbed hydrogen molecules per unit area correlates well with the density of organic groups on the pore surface. We attribute the high Q_st to the high polarizability of organic groups with π electrons, which enhances the dispersion force. The molecular order of organic groups affects the adsorption-site affinity to hydrogen molecules as well as the location of adsorption sites. For phenylene-bridged PMOs with crystal-like pore walls, Q_st decreases rapidly with increasing hydrogen loading, which indicates two types of adsorption sites with different affinities to hydrogen molecules: one is an exposed CH bond and the other is a siloxane bond. However, Q_st for phenylene-bridged PMOs with amorphous pore walls exhibits a moderate slope, which might be caused by the random order of organic groups; this results in several types of adsorption sites with various affinities.     

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...     

功能化介孔材料吸附性能与机理的研究进展

综述了功能化介孔材料的孔径结构、改性基团和吸附条件对废水中的有机污染物、染料分子和重金属离子以及生物大分子、药物分子、CO2和挥发性有机气体污染物的吸附脱除效果的影响,还介绍了功能化介孔材料对液晶材料中的微量无机离子和大极性有机杂质的吸附脱除效果,指出了新型功能化介孔材料的开发和吸附环境的研究是未来的研究热点和发展趋势。     

表面有机化钛酸材料的制备及吸附染料性能

将K2CO3和TiO2通过高温固相反应制得K2Ti4O9,经酸化处理后得到H2Ti4O9,用正十二胺乙醇溶液与之反应,获得正十二胺柱撑的层状化合物,采用X射线衍射(XRD)、红外光谱(IR)等方法对所得材料进行结构表征,并初步研究了有机胺支撑前后钛酸材料的吸附性能,实验结果表明:在钛酸钾材料的层间引入正十二胺有机基团后,层间距加大,吸附能力大大提高。