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1.
Phani Rallapalli Dinesh Patil K. P. Prasanth Rajesh S. Somani R. V. Jasra H. C. Bajaj 《Journal of Porous Materials》2010,17(5):523-528
An alternative solvent extraction method is reported for the activation of hydrothermally synthesized aluminium terephthalate,
MIL-53(Al) eliminating the calcination step conventionally used for the removal of unreacted benzenedicarboxylic acid entrapped
in the cavities/pores of as-synthesized MIL-53(Al). The surface area and micropore volume of the MIL-53(Al) activated by solvent
extraction method (1235 m2/g) were higher than the MIL-53(Al) activated by conventional calcination method (1073 m2/g). Methane adsorption studies on MIL-53(Al) samples were carried out at 303 K up to 35 bar pressure. The solvent extracted
MIL-53(Al) showed an enhanced methane storage capacity of 186 cm3/cm3 compared to the calcined MIL-53(Al) (158 cm3/cm3) at 303 K and 35 bar. 相似文献
2.
Aluminum terephthalate, MIL-53(Al), metal–organic framework synthesized hydrothermally and purified by solvent extraction
method was used as an adsorbent for gas adsorption studies. The synthesized MIL-53(Al) was characterized by powder X-Ray diffraction
analysis, surface area measurement using N2 adsorption–desorption at 77 K, FTIR spectroscopy and thermo gravimetric analysis. Adsorption isotherms of CO2, CH4, CO, N2, O2 and Ar were measured at 288 and 303 K. The absolute adsorption capacity was found in the order CO2>CH4>CO>N2>Ar>O2. Henry’s constants, heat of adsorption in the low pressure region and adsorption selectivities for the adsorbate gases were
calculated from their adsorption isotherms. The high selectivity and low heat of adsorption for CO2 suggests that MIL-53(Al) is a potential adsorbent material for the separation of CO2 from gas mixtures. The high selectivity for CH4 over O2 and its low heat of adsorption suggests that MIL-53(Al) could also be a compatible adsorbent for the separation of methane
from methane–oxygen gas mixtures. 相似文献
3.
《分离科学与技术》2012,47(13):1995-2003
Metal-organic framework MIL-53(Al) pellets were tested for the selective adsorption and separation of xylene isomers, in liquid phase and using n-heptane as eluent. The objective of this work is to assess relevant data for a posterior xylene isomers separation process design. In order to complete this study, single and multi-component breakthrough experiments were performed at 313 K, in the presence of n-heptane. MIL-53(Al) presented a preference for o-xylene over m-xylene and p-xylene in all experiments. The selectivities of 2.0 were obtained for o-xylene over m-xylene and over p-xylene. It is concluded that MIL-53(Al) may be used for separating o-xylene from the other xylene isomers, using n-heptane as desorbent. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science & Technology to view the free supplemental file. 相似文献
4.
V. Finsy L. Ma L. Alaerts D.E. De Vos G.V. Baron J.F.M. Denayer 《Microporous and mesoporous materials》2009,120(3):221-227
Adsorptive separation of CH4/CO2 mixtures was studied using a fixed-bed packed with MIL-53(Al) MOF pellets. Such pellets of MIL-53(Al) were produced using a polyvinyl alcohol binder. As revealed by N2 adsorption isotherms, the use of polyvinyl alcohol as binder results in a loss in overall capacity of 32%. Separations of binary mixtures in breakthrough experiments were successfully performed at pressures varying between 1 and 8 bar and different mixture compositions. The binary adsorption isotherms reveal a preferential adsorption of CO2 compared to CH4 over the whole pressure and concentration range. The separation selectivity was affected by total pressure; below 5 bar, a constant selectivity, with an average separation factor of about 7 was observed. Above 5 bar, the average separation factor decreases to about 4. The adsorption selectivity is affected by breathing of the framework and specific interaction of CO2 with framework hydroxyl groups. CO2 desorption can be realised by mild thermal treatment. 相似文献
5.
将来瓦希尔骨架材料MIL-53(Al)引入到聚醚共聚酰胺(PEBA-2533)高分子相中制备了不同填充量的PEBA/MIL-53(Al)杂化膜并用于渗透汽化分离水中微量苯胺。X-射线衍射结果证实MIL-53(Al)被成功合成。扫描电镜和激光粒度分析结果表明所制备MIL-53(Al)颗粒粒径在纳米尺度范围内。采用扫描电镜、红外光谱、X-射线衍射、差示扫描量热和水接触角对杂化膜进行了表征,并考察了杂化膜的溶胀行为和分离性能。结果表明,所得杂化膜的热稳定性较好。当MIL-53(Al)质量分数小于20%时,MIL-53(Al)在高分子相中分散均匀,继续增大填充量出现团聚现象。杂化膜的结晶度随MIL-53(Al)填充量的增加而降低。MIL-53(Al)的引入增强了杂化膜的疏水性和溶胀度。在料液温度为60℃、膜下游压力400Pa、料液苯胺质量分数为3.6%时,MIL-53(Al)质量分数为20%的杂化膜(M-20)综合分离性能最优,渗透通量达到2.15kg/(m2·h),分离因子为264。12天的稳定性测试结果表明所得杂化膜分离性能无显著变化,能够满足渗透汽化应用要求。 相似文献
6.
Jinlong Ge Lingli Liu Lingguang Qiu Xia Jiang Yuhua Shen 《Journal of Porous Materials》2016,23(4):857-865
An amine functional MIL-53(Al) material was prepared through a clean, rapid, energy-efficient method of microwave and ultrasound irradiation. The pure phase NH2-MIL-53(Al) can be formed in 25 min, utilizing the synergistic effect of microwave and ultrasound irradiation. The dramatic acceleration in reaction rates suggested that the removal of a passivation coating on the substrate particles and the resultant enhancement in mass and heat transfer. The porous MOFs exhibited a high thermal and chemical stability, decomposing at temperatures above 410 °C in air. The NH2-MIL-53(Al) performed an excellent adsorption for CO2. The CO2 capacities up to 33.86 cm3 g?1 at 298 K at low pressures, which suggests chemisorption between CO2 and pendan amine groups. Measurement of CO2 adsorption cycles proved that the functionalized materials show good regenerability and stability. 相似文献
7.
The highly dispersed CuO@CeO2 catalysts were produced from Cu/MIL-53(Ce) through encapsulated copper in a matrix of metal organic framework MIL-53(Ce), serving as a catalyst for CO oxidation. Comparison on the catalytic performance between the CuO@CeO2 and the (CuO or MIL-53(Ce)) catalytic material has been conducted to understand the catalytic behavior of the catalysts. The CuO@CeO2 catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption-desorption, and the hydrogen temperature-programmed reduction (H2-TPR). The analyses indicated that the unique CuO@CeO2 spatial confinement in the obtained solids minimize catalyst deactivation, resulting in high active and stable operation. Indeed, the heterogeneous catalytic composite materials CuO@CeO2 catalyst exhibited excellent activity in CO oxidation test, with 100% conversion at 79–95 °C and the catalytic activity were stable after reaction 300 h. 相似文献
8.
《Ceramics International》2023,49(4):5977-5985
The efficient TiO2 NTs/Sn3O4 photocatalysts were synthesized by the hydrothermal deposition of Sn3O4 on TiO2 nanotube arrays (TiO2 NTs), and the morphology, microstructure and photocatalytic property were adjusted by changing the alkali kind. The TiO2 NTs/Sn3O4 prepared with NaOH exhibited the outstanding photoelectric conversion and photocatalytic environment remediation/H2 evolution. The methylene blue (MB) dye and Cr(VI) could be removed by the as-prepared photocatalysts under visible light irradiation, and ?O2?/?OH radicals were the main active species for MB photodegradation. Furthermore, the high photocatalytic H2 evolution rate was as high as 6.49 μmol cm?2 h?1. The outstanding photocatalytic activity and stability of TiO2 NTs/Sn3O4 photocatalysts would exhibit attractive prospect in the wastewater remediation and electric energy/hydrogen generation. 相似文献
9.
Jinkai Zhou Masato Takeuchi X. S. Zhao Ajay K. Ray Masakazu Anpo 《Catalysis Letters》2006,106(1-2):67-70
Unique visible-light-responsive TiO2 photocatalysts (λ>450 nm) were successfully developed by implantation of V ions into the TiO2 thin films prepared on a quartz substrate by an ionized cluster beam (ICB) deposition method. After V ions implantation into
TiO2 thin film, the photocatalytic activity of the thin films for the decomposition of formic acid into CO2 and H2O was found to proceed efficiently under visible light irradiation longer than 450 nm. The TiO2 thin film photocatalysts were characterized by XRD, UV-vis, XPS, FE-SEM and AFM. 相似文献
10.
Yuhang Wang Chunmei Li Jiaojun Tan Wenbin Wang Qiuyu Zhang Hongxia Yan 《Journal of Porous Materials》2017,24(3):639-646
In this paper, the core–shell structured NiFe2O4@TiO2 nanoparticles and nanochains as photocatalysts were successfully prepared through hydrothermal and hydrolysis method. The as-prepared core–shell structure was composed of a magnetic NiFe2O4 core and photocatalytic titanium oxide coating shell. SEM and TEM images characterized the morphology of NiFe2O4@TiO2 nanoparticles. Moreover, the results of XRD patterns proved that the TiO2 coating shell consisted of anatase. The VSM measurements showed that the saturation magnetization values of NiFe2O4 and NiFe2O4@TiO2 nanoparticles was 65 and 53 emu/g, respectively. The photocatalyst of NiFe2O4@TiO2 nanoparticles exhibited the outstanding recyclable performance for RhB. And, the photo_degradation ration of maintained 69 % after the photocatalyst experienced ten photocatalysis experiments, which is better than that of Fe3O4@TiO2 photocatalysts. 相似文献
11.
Here, the mixed metal nodes MOFs, Pd/MIL-100(FeaCub), were constructed as photocatalysts for hydrogenation of α, β-unsaturated aldehyde (UAL) under visible light. 1 wt% Pd/MIL-100(Fe0.81Cu0.19) can convert a range of UAL to saturated aldehydes (SAL) with a high efficiency (≈ 100 %) and selectivity (≈ 98 %). The results of XPS and in situ DRIFTS reveal that UAL can be selectively activated via a coordination of -CC- on Cu2+ sites, determining the high selectivity of the photocatalytic reaction. The mixed metal nodes and Pd clusters can improve the transformation and separation of photogenerated electrons-holes. EPR result suggests that photogenerated carriers can facilitate the generation of H·on Pd/MIL-100(Fe0.81Cu0.19), enhancing the catalytic activity. A possible mechanism is proposed for elucidating the catalytic processes at the molecular level. This work provides a valuable strategy for tailoring the selectivity of photocatalytic hydrogenation via selective coordination activation. 相似文献
12.
Two metal organic frameworks (MOFs), chromium benzenedicarboxylates MIL-101 and MIL-53, have been synthesized and used as the support of palladium catalysts. The palladium catalysts were characterized by XRD, TEM, and CO chemisorption. MIL-101 is highly hydrophilic and beneficial as support for fine Pd nanoparticles with an average size of 2.3 nm. Microporous MIL-53 is relatively hydrophobic and larger Pd particles with an average size of 4.3 nm were formed on the external surface. Pd/MIL-101 showed better phenol selective hydrogenation activity to cyclohexanone (> 98%) under mild reaction conditions because of its smaller particle size. 相似文献
13.
Polymer/semiconductor oxide nanocomposite films have been intensively investigated for various applications. In this work, we reported a simple hydrothermal method to fabricate highly transparent poly(vinyl alcohol)/titanium dioxide (PVA/TiO2) nanocomposite films with enhanced visible-light photocatalytic activity. The as-prepared PVA/TiO2 nanocomposite films showed high optical transparency in the visible region even at a high TiO2 content (up to 40 wt.%). The determination of photocatalytic activity by photodegradation of methyl orange (MO) and colorless phenol showed that PVA/TiO2 nanocomposite films exhibited enhanced visible-light photocatalytic activity and excellent recycle stability. This work provided new insights into fabrication of polymer/TiO2 nanocomposites as high performance photocatalysts in waste water treatment. 相似文献
14.
《Ceramics International》2020,46(12):20155-20162
Anatase TiO2 nanoparticles (NPs) were successfully prepared through a hydrothermal approach, and Au NPs at various Au (0.1–2 wt%) contents were photodeposited onto the TiO2 NPs surface. The photocatalytic efficiency for the Au/TiO2 NPs for resorcinol photodegradation throughout UVA illumination was assessed. The TEM images and XPS findings indicated that the Au NPs are highly distributed onto TiO2 surface in the metallic state. The 0.1%Au/TiO2 NPs exhibited the highest photocatalytic efficiency of about 95.34%; however, 72.36% is given by pure TiO2 NPs. It was found that the photodegradation rate of 0.1% Au/TiO2 NPs exhibited 1.5 times of magnitude higher than pure TiO2 NPs. 0.1%Au/TiO2 NPs was considered to be the outstanding photoactive due to the ultimate efficient charge-carriers separation through charge transfer between Au and TiO2 NPs. The Au NPs sizes, its dispersity on TiO2 surface and surface plasmon resonance (SPR) were believed the critical factors for the higher photocatalytic performance of 0.1% Au/TiO2 NPs. The prepared photocatalysts are found to be the promising materials for toxic organic compounds remediation and solar conversion. 相似文献
15.
Robust visible-light Gd–La codoped TiO2 nanotubes were successfully synthesized via an ultrasonic hydrothermal method and the photocatalytic activities were evaluated by photodegrading Rhodamine B (RB). The calcined Gd–La codoped TiO2 nanotubes have significantly enhanced photocatalytic activities than the uncalcined ones. The La3+ and Gd3+ in the lattices of rare earth oxides may be substituted by Ti4+, creating abundant oxygen vacancies and surface defects for electron trapping and dye adsorption, accelerating the separation of photogenerated electron–hole pairs and RB photodegradation. The formation of an excitation energy level below the conduction band of TiO2 from the binding of electrons and oxygen vacancies decreases the excitation energy of Gd–La codoped TiO2 nanotubes, resulting in robust photocatalysts. The results suggest that Gd–La codoped TiO2 nanotubes calcined at 500 °C are very promising for enhancing the photocatalytic activity of photocatalysts in visible-light region. 相似文献
16.
《Ceramics International》2021,47(20):28296-28303
Although TiO2 is a wide band gap semiconductor, it demonstrates photodegradation activity under visible light irradiation after dye sensitization. Compared with esterification between the surface hydroxyl group of TiO2 and the carboxylic group of dyes, electrostatic interaction between TiO2 and dye shows better photosensitized performance. In this work, Bi/Al co-doping anatase titania (Ti1-xBi2x/3Al2x/3O2 (0 ≤ x ≤ 0.3)) is designed to enhance the electrostatic interaction. The effect of Al ions is to enhance the solubility of Bi3+ into titania nanocrystals. A new band gap is generated after high concentration of Bi element doping, which not only promotes the absorption of visible light, but also improves the utilization of photogenerated carriers. Based on the results of transmission electron microscopy, light absorption, photodegradation activity and density functional theory calculations, it is found that bismuth dopant is the electron capture site. It first accumulates electrons through photocatalytic degradation reaction to enhance electrostatic adsorption between the catalyst and the positively charged dye molecules, and finally realizes high-efficiency photosensitization degradation of Rhodamine B. In addition, the sensitized titania has excellent photodegradation recyclability. 相似文献
17.
This study focused on toluene photodecomposition in the presence of H2O over metal (Ba, Al, Si, V, and W)-incorporated TiO2. The nanometer-sized, metal-TiO2 photocatalyst samples, including Ba2+, Al3+, Si4+, V5+, and W6+ ions, were prepared by using the solvothermal method. The X-ray photoelectron spectroscopy (XPS) results showed that the
Ti-OH peak, which indicates hydrophilicity, increased with increasing Al and Si ion components but decreased with increasing
Ba, V, and W ion components. The contact angles were distributed over the range of 0–10° on almost all films (200-nm thick)
after irradiation for 2 h, and in particular approached 0° on the Al-TiO2 and Si-TiO2 nanometer-sized films after just 30 min. The toluene (100 ppm) photodecomposition in the continuous system increased in the
order of Al-TiO2>Si-TiO2>pure TiO2>W-TiO2>Ba-TiO2>V-TiO2, and the maximum toluene conversion rate achieved was 45% over Al-TiO2 film after 120 min. The toluene conversion remarkably increased; however, over all photocatalysts, with H2O addition during the toluene photo-decomposed reaction, and in particular, the conversion reached up to 90% after 120 min
over Al-TiO2 and Si-TiO2 with increased hydrophilicity. After photoreaction for 24 h, minimal carbon was deposited on the photocatalyst under both
reaction conditions, with and without H2O addition, although the deposited carbon amounts were smaller for the former. These results confirmed that the hydrophilicity
of the photocatalyst had a greater effect on toluene decomposition, while the photocatalytic deactivation could be retarded
by H2O supplementation during toluene decomposition. 相似文献
18.
Il-Kyu Kim Hyun-Jung Ha Sang-Keun Lee Jea-Keun Lee 《Korean Journal of Chemical Engineering》2005,22(3):382-386
In this research, the photocatalytic degradation of 4-chlorophenol (4-CP) in TiO2 aqueous suspension was studied. TiO2 photocatalysts were prepared by sol-gel method. The dominant anatase-structure on TiO2 particles was observed after calcining the TiO2 gel at 500 °C for 1 hr. Photocatalysts with various transition metals (Fe, Cu, Nd, Pd and Pt) loading were tested to evaluate
the effect of transition metal impurities on photodegradation. The photocatalytic degradation in most cases follows first-order
kinetics. The maximum photodegradation efficiency was obtained with TiO2 dosage of 0.4 g/L, retention time of 1 min and air flow rate of 2,500 cc/min. The photodegradation efficiency with Pt-TiO2 or Pd-TiO2 is higher than pure TiO2 powder. The optimal content value of Pt and Pd is 2 wt%. However, the photodegradation efficiency with Fe(1.0 wt%)-TiO2 and Cu(1.0 wt%)-TiO2 is lower than pure TiO2 powder.
This paper was prepared at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November
3 and 4, 2004. 相似文献
19.
Jae-Hyoung Park Yong-Su Seo Hyun-Seung Kim Il-Kyu Kim 《Korean Journal of Chemical Engineering》2011,28(8):1693-1697
The photodegradation of BTEX (benzene, toluene, ethylbenzene and xylene) in a photocatalytic fluidized bed reactor with TiO2/SiO2 was investigated. The TiO2 film was prepared using the sol-gel method and coated onto silica-gel powder. The effects of the superficial gas velocity
and SiO2 size on the photodegradation of BTEX were examined in a fluidized bed reactor. At steady-state operation, above 79, 79, 99,
98, and 98% removal efficiencies were achieved for benzene, toluene, ethylbenzene, m, p-xylene and o-xylene, respectively,
under optimal conditions (2.0 U
mf
of superficial gas velocity and 1.43 of height/diameter ratio). The reaction product such as CO2 was detected and intermediate products such as benzaldehyde, malonic acid, acetaldehyde, and formic acid were identified
from the photocatalytic reaction. Also, small amounts of benzoic acid and benzyl alcohol were found through analyzing the
intermediate species adsorbed on the photocatalysts. The experimental results can lead to the development of an efficient
photocatalytic treatment system that utilizes solar energy and TiO2/SiO2 photocatalysts. 相似文献
20.
《Ceramics International》2017,43(6):4866-4872
A unique Cu2O/TiO2 nanocomposite with high photocatalytic activity was synthesized via a two-step chemical solution method and used for the photocatalytic degradation of organic dye. The structure, morphology, composition, optical and photocatalytic properties of the as-prepared samples were investigated in detail. The results suggested that the Cu2O/TiO2 nanocomposite is composed of hierarchical TiO2 hollow microstructure coated by a great many Cu2O nanoparticles. The photocatalytic performance of Cu2O/TiO2 nanocomposite was evaluated by the photodegradation of methylene blue (MB) under visible light, and compared with those of the pure TiO2 and Cu2O photocatalysts synthesized by the identical synthetic route. Within 120 min of reaction time, nearly 100% decolorization efficiency of MB was achieved by Cu2O/TiO2 photocatalyst, which is much higher than that of pure TiO2 (26%) or Cu2O (32%). The outstanding photocatalytic efficiency was mainly ascribed to the unique architecture, the extended photoresponse range and efficient separation of the electron-hole pairs in the Cu2O/TiO2 heterojunction. In addition, the Cu2O/TiO2 nanocomposite also retains good cycling stability in the photodegradation of MB. 相似文献