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Abstract: A novel membrane reactor was designed for the ozonolysis of refractory organic pollutants in water. The reactor employed a membrane contactor and a membrane separator in a concentric arrangement to affect a uniform ozone distribution along the reactor length, while allowing the simultaneous membrane separation and production of clean water. An alumina capillary membrane contactor and a ZSM-5 zeolite pervaporation membrane were used in this study. Using potassium hydrogen phthalate as model pollutant, the performance of the novel membrane reactor was tested and compared to ozone reaction carried out using the capillary membrane contactor and membrane pervaporation using the ZSM-5 membrane. The novel membrane reactor consistently outperformed both membrane processes. Forty-seven percent higher TOC degradation was observed compared to ozone reaction using a capillary membrane contactor. This enhancement is due to the increase in the organic pollutant concentration in the reaction zone as a result of water withdrawal by membrane pervaporation. As in the case of membrane pervaporation, clean water was produced at the permeate outlet of the novel membrane reactor. Clean water with less than 0.5±0.1ppm was collected from the membrane permeate outlet at a rate of 11–15kg−1 h−1 m−2. [Copyright &y& Elsevier]

Abstract: Two types of membrane reactors, the packed-bed membrane reactor (PBMR) and catalytic membrane reactor (CMR) were successfully miniaturized. Zeolites were incorporated as catalyst for reaction and membrane for separation. The membrane microreactors were tested for Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate to produce ethyl 2-cyano-3-phenylacrylate. Supra-equilibrium conversion and high product purity were obtained from selective removal of water during the reaction. A simple computation model was developed to simulate the reaction in the multichannel membrane microreactor using kinetic data from batch reaction, correlated data from membrane separation and published transport data. The influence of reactor geometry (i.e. channel width and membrane location), membrane separation and catalyst properties were evaluated and the results compared well with experimental data. The information provided by the model suggests several ways of improving the reactor performance. [Copyright &y& Elsevier]

Pd membranes of excellent stability and flux were prepared with multi-legged anchors by electroless plating of Pd on a porous support modified by a zeolite barrier layer containing Pd seeds; these membranes provide stable phenol production by direct hydroxylation of benzene. [ABSTRACT FROM AUTHOR]

Abstract: Freestanding Sil-1 and ZSM-5 micromembranes of Si/Al ratios ranging from 14 to ∞ were fabricated on silicon. The zeolite synthesis was adjusted to obtain micromembranes of similar microstructures (i.e., thickness, orientation, crystal grain size, morphology and intergrowth) and prepared membranes display comparable helium gas permeance. The low temperature removal of the organic TPA+ molecules by ozone enabled the preparation of low defect zeolite micromembranes that exhibit superb H2/nC4 (i.e., ≥100) and nC4/iC4 (i.e., ≥30) permselectivity ratios. The effects of aluminum content of the ZSM-5 micromembranes were investigated for single, binary and ternary gas permeation. Surface diffusion is important at low temperature and the single gas permeances of hydrogen, argon, nitrogen and methane were larger than Knudsen. The deviation from Knudsen increased with the Si/Al ratio and was largest for Sil-1. Propane–nitrogen separation in the zeolite micromembranes is mainly molecular sieving and display weak dependence on the aluminum content of the zeolite, where the separation of the ternary H2–CH4–CO2 mixture is by preferential adsorption and shows strong dependence on the Si/Al ratio of the zeolite. [Copyright &y& Elsevier]

Abstract: An alkali-resistant catalyst for direct internal reforming molten carbonate fuel cell (DIR-MCFC) is prepared by growing a thin shell of mesoporous MSU-1 membrane on Ni/Al2O3 catalyst beads. The MSU-1 shell is obtained by first depositing a monolayer of colloidal silicalite-1 (Sil-1) on the catalyst bead as linkers and then using NaF stored in the beads to catalyze the growth of the MSU-1 layer. The resulting core–shell catalysts display excellent alkali-resistance and deliver stable methane conversion and hydrogen yield in an out-of-cell test simulating the operating conditions of an operating DIR-MCFC. Higher conversion and yield (i.e., up to over 70%) are obtained from the new core–shell catalyst with MSU-1 shell compared to the catalyst with microporous Sil-1 shell. A mathematical model of the reaction and poisoning of the core–shell catalyst is used to predict the optimum shell thickness for its reliable use in a DIR-MCFC. [Copyright &y& Elsevier]

Abstract: Pd membrane with excellent stability was prepared on macroporous α-Al2O3 tubes using a nanoporous Sil-1 zeolite as an intermediate support and diffusion barrier layer. The detailed microstructure of the composite membrane was examined by scanning electron microscopy and mapped by EDXS and EPMA to reveal a palladium membrane anchored by multi-legs Pd protrutions that penetrates through the interstices of the zeolite grains into the seed layer. This membrane architecture allowed the membrane to tolerate rapid and repeated cycling of gases, temperature and pressure over 300h without lost of permeance and selectivity. The zeolite layer contributed up to 25% of the transport resistance across the Pd–Sil-1 composite membrane and has a significant effect on the hydrogen permeance. [ABSTRACT FROM AUTHOR]

The performance of a membrane microreactor was tested and compared with that of a microreactor, a packed bed reactor (PBR) and a packed bed membrane reactor (PBMR) for the Knoevenagel condensation reaction of benzaldehyde and ethyl cyanoacetate to produce ethyl 2-cyano-3-phenylacrylate. Cs-exchanged NaX faujasite zeolite was used as the base catalyst for this equilibrium-limited reaction. Hydrophilic ZSM-5 membranes were employed in both the membrane microreactor and the PBMR for the selective removal of water byproduct from the reaction. The product yield per pass was low for the packed bed reactor. Higher yields were observed for the microreactor and PBMR, but the best performance belongs to the membrane microreactor, which displayed both supra-equilibrium conversion and better product purity. [Copyright &y& Elsevier]