MOF-5 is an important metal-organic framework and has been intensely studied, especially in its hydrogen storage properties. In this study, we obtained the interpenetrated MOF-5 materials (MOF-5int) using N,N 0 -dimethylformamide (DMF) or N,N 0 -diethylformamide (DEF) as solvents. The Langmuir surface area of MOF-5-int determined by N 2 adsorption is 950-1100 m 2 g À1 , much lower than the non-penetrated MOF-5 (3000 m 2 g À1 ). However, it can store 1.54-1.82 wt% by volumetric method hydrogen at 77 K and 1 atm, which is higher than the amount stored by the non-penetrated MOF-5. The MOF-5-int was also characterized by XRD-powder diffraction, thermogravimetric analysis (TGA), nitrogen adsorption/desorption analysis, scanning electron microscope (SEM) and X-ray single-crystal structure diffraction. In addition, we found grinding greatly facilitates the decomposition of the MOF-5-int material by H 2 O to a nonporous phase ZnBDC$xH 2 O (within 2-5 min, BDC ¼ 1,4-benzenedicarboxylate), even under low humidity (30%), which calls for careful handling of the MOF-5 material. The effects of the water content, reaction time, reaction temperature, molar ratio of Zn(NO 3 ) 2 to H 2 BDC, addition of H 2 O 2 , rapid stirring and dilution on the synthesis of MOF-5-int were studied and the synthetic conditions were optimized. Moreover, Hafizovic et al. (J. Am. Chem. Soc., 2007, 129, 3612) found the intensity ratio of the powder XRD peak at 9.7 to that at 6.8 (referred to as the R 1 value) of MOF-5 can be used to predict its porosity. The lower the intensity ratio, the more porous it is. In this study, we showed that MOF-5-int can have a very low R 1 value but also a low porosity. The low specific surface area (SSA) is mainly due to its interpenetrated structure instead of the entrapped zinc species or the mesopores in the material, as previously proposed in the literature, and associated with the characteristic, very strong peak at 13.8 in its XRD-powder diffraction pattern. A high R 2 value (the ratio of the intensity of the peak at 13.8 to that at 6.8 ) suggests an interpenetrated structure, especially when the R 1 value is low. In addition, we found that although entrapped ZnO or solvent molecules can increase the R 1 value, and a low R 1 value implies no zinc species or solvent molecules entrapped in the MOF-5 framework, a high R 1 value does not necessarily suggest the presence of entrapped molecules.

A new magnetic mesoporous carbon composite (Fe3O4/C) was synthesized and characterized by XRD, nitrogen adsorption–desorption isotherms, FT-IR, TG, ζ potential, SEM, and TEM. The performance of using Fe3O4/C composite as an adsorbent for removal of antibiotics using ciprofloxacin (CIP) as a model was investigated. The Langmuir adsorption isotherm was applicable to fit the removal process. Kinetics of the CIP removal was found to follow a pseudo-second-order rate equation. The solution pH is critical for the adsorption of CIP on Fe3O4/C, and the maximum adsorption of CIP could be reached under neutral conditions. In addition, the Fe3O4/C adsorbent showed high magnetization and operational stability, and it could be readily separated from solution by applying an external magnetic field. After 10 recycle runs, over 85% of the adsorption capacity was retained. The high performance, low cost, and easily recyclable Fe3O4/C composite may become a promising adsorbent for water treatment.

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Abstract:A novel melamine-formaldehyde resin (MFR) supported solid acid with Lewis and Brønsted acid sites was synthesized through the immobilization of acidic ionic liquid and cuprous ion on MFR. The scanning electron microscopy (SEM) characterization showed that addition of PEG-2000 in the synthesis of MFR could promote the formation of regular particles with diameters around 3.7 µ m. The XRD pattern demonstrated that some cuprous ions were aggregated. The catalytic performance of this acid catalyst was evaluated by acetalization. The results showed that the catalytic activity of MFR with Brønsted acid could be improved by addition of Lewis acid. The solid acid was very efficient for the acetalization of carbonyl compounds and diols with moderate to excellent yields and there was no loss of catalytic activity even after being recycled for 6 runs.

A DFT study of the catalytic properties of CuO/CNT and CuO@CNT complexes for the heterogeneous catalytic ozonation has been performed. We illustrated the atomistic details of CuO/CNT and CuO@CNT with a quantitative and qualitative discussion within such an electronic structure characteristics. Ozone was catalytically decomposed into an atomic oxygen species and oxygen molecule on both the surface inner and outer CuO@CNT complex, while ozone can only decompose over CuO on the outer surface of CuO/CNT, with partial electrons transfer from CuO/CNT and CuO@CNT complexes to the adsorbate. Then the atomic oxygen reacted with the water molecule to form two hydroxyl groups on the surface, promoting the reaction chain for the generation of•OH which, in turn, lead to an increase in the catalytic ozonation efficiency. Results show synergetic confinement effect of metal oxide nanoparticles inside CNT could also lead to an acceleration of ozone decomposition and the generation of •OH on the inner and outer surface of carbon-nanotube containing catalytic particles.