The preparation of stable metal–organic framework tubular membranes for liquid mixture separation has always been a tough problem. Herein, a flexibly prepared, continuous, and stable Al-based CAU-10 membrane with ceramic tubes as support was developed by a thin γ-Al2O3 layer induction method and employed for the first time in the separation of MeOH/MTBE azeotropic mixtures through pervaporation. The γ-Al2O3 layer introduced on the tube by the dip-coating technique not only facilitated the crystal nucleation and continuous growth of CAU-10 membranes but also reinforced the membrane stability by acting as anchoring sites between the membrane and the substrate. The as-prepared CAU-10 tubular membrane exhibited excellent separation performance for MeOH/MTBE mixtures owing to its suitable pore size and good hydrophilicity. For the separation of 14.3 wt % MeOH/MTBE azeotropic mixtures, the membrane displayed a permeation flux of 1.76 kg/(m2 h) and a high separation factor of 2041 at 50 °C, which is better than most of the membranes reported for the pervaporation separation of MeOH/MTBE mixtures. More excitedly, the CAU-10 tubular membrane continued to be tested for more than 7 days without any obvious change in pervaporation performance, demonstrating its outstanding operational and hydrothermal stability. Accordingly, the CAU-10 tubular membrane would be a promising alternative to separate the MeOH/MTBE azeotropic mixtures due to its easy preparation, high performance, and excellent stability.
Yang Yu,Xiaoping Cai,Xinyang Jiao,Chengyi Xu,Jinan Niu,Peizhong Feng
Ni-Al-Cr intermetallic compounds are candidate at extreme environment due to their excellent oxidation resistance at high temperature, and the oxidation resistance of Ni-Al-Cr alloy system has been studied extensively. However, the research on oxidation resistance mechanism of porous Ni-Al-Cr intermetallic compounds is still not deep. In our work, porous Ni-Al-Cr intermetallic compounds were synthesized by thermal explosion, and the oxidation resistance of porous Ni-Al-Cr system was mainly investigated. The results indicate that Cr promotes the formation of highly protective continuous Al 2 O 3 layer, increasing the oxidation resistance at 900 °C of porous Ni-Al-Cr. After oxidation at 900 °C for 120 h, the minimum mass gain of Ni-Al-Cr products is only 6.96%.
In this paper, a photocatalytic system for effectively degrading azo dyes is described. The nanostructured porous Al 2 O 3 layer on glass substrate (PAOG)/silver nanoparticles (AgNPs)–Hemin composites were synthesized via photochemical reduction of Ag, self-assembly of 11-mercaptoundecanoic acid (MUA) on AgNPs and subsequently linking Hemin to MUA via coordination bond. PAOG as a nanoporous template was chemically durable, highly porous and allowed chemicals conveniently immobilized on the glass surface. PAOG had a BET surface area of 151 m 2 /g which facilitated the immobilization of AgNPs. The composite was characterized by BET surface area measurements, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared (FTIR) spectrometer and X-ray photoelectron spectroscopy (XPS). The photoreaction degradation processes were examined by UV/vis spectroscopy. Methyl orange (MO) and Acid red 18 solutions were used to evaluate the photocatalytic performance of PAOG/AgNPs–Hemin composite under visible light and UV irradiation. Compared with PAOG/Hemin, the PAOG/AgNPs–Hemin composite had enhanced photocatalytic efficiency due to higher electron transfer efficiency from AgNPs to Hemin. This novel composite with enhanced broad spectrum photocatalytic properties has promising potentials in degradation of dyes by UV and visible light utilization.
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