Functional catalytic membrane development: A review of catalyst coating techniques.

Covalent organic frameworks (COFs) have emerged as an excellent support for heterogeneous catalysis due to their regular pore structure and high specific surface area. Herein, a series of porous Tp...

Pd Nanoparticles Loaded on Two-Dimensional Covalent Organic Frameworks with Enhanced Catalytic Performance for Phenol Hydrogenation

Catalytic nanofiber composite membrane by combining electrospinning precursor seeding and flowing synthesis for immobilizing ZIF-8 derived Ag nanoparticles

With the PTFE membrane as the substrate, a novel Ag-based catalytic membrane reactor (CMR) was fabricated by deep-permeation synthesis fabrication (DPSF). In DPSF, ZIF-8 was first assembled inside ...

Catalytic Membrane Reactor of Nano (Ag+ZIF-8)@Poly(tetrafluoroethylene) Built by Deep-Permeation Synthesis Fabrication

Here, we report on a green and effective method for the continuous and complete conversion of high concentrations of p-nitrophenol (PNP) using a flow-through membrane reactor and less NaBH4 The catalytic membrane was successfully fabricated by loading Pd nanoparticles onto the surface of a branched TiO2 nanorod-functionalized ceramic membrane The modification with branched TiO2 nanorods can significantly improve the loading amount of Pd nanoparticles onto ceramic membranes, resulting in enhanced catalytic performance With 6 mg of Pd, 93 L m−2 hr−1 of flux density and 804 cm2 of membrane surface area in the flow-through membrane reactor, PNP at a concentration of 4,000 ppm can be converted to high-value p-aminophenol using less NaBH4 (using a molar ratio of NaBH4:PNP of 96) within 24 s at 30°C More importantly, the conversion can be continuously and stably performed for 240 min

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Continuous and complete conversion of high concentration p-nitrophenol in a flow-through membrane reactor

A high performance catalytic membrane was fabricated with Pd nanoparticles supported by TiO2 nanotubes, where the TiO2 nanotubes were synthesized on the ceramic membrane via a simple hydrothermal etching. A flow-through catalytic membrane reactor was developed for testing the catalytic properties in the p-nitrophenol reduction. The effect of etching time was investigated in detail and an optimal etching time was determined to be 16 h. The characterization results highlighted that the as-prepared bouquet-like TiO2 nanotubes could significantly improve the loading amount and dispersity of Pd nanoparticles. The fabricated catalytic membrane exhibited considerably improved catalytic activity and stability, with a 100% conversion of p-nitrophenol and no loss in catalytic activity during five reaction cycles. The obtained activation energy was much lower than the values in literatures, implying that the p-nitrophenol reduction could take place more easily on our catalytic membranes compared to other catalysts.

Pd nanoparticles immobilized on TiO2 nanotubes-functionalized ceramic membranes for flow-through catalysis

The invention relates to a preparation method of a supported catalyst for circulating type catalytic reaction. The catalyst uses a ceramic membrane as a carrier. The preparation method comprises the following steps: growing TiO2 nanorods on the surface and in pore passages of a ceramic membrane by a two-step hydrothermal method, then etching the TiO2 nanorods into TiO2 nanotubes by a hydrochloricacid hydrothermal etching method, modifying through a silane coupling agent to introduce amino functional groups, and finally, loading Pd nanoparticles by a sol impregnation method to prepare the supported catalyst. The preparation method has the advantages that the surface and the pore passages of the ceramic membrane are modified through the TiO2 nanotubes, so that the surface area of the membrane catalyst can be expanded, more Pd nanoparticles are loaded on the surface and in the pore passages of the ceramic membrane, and the catalytic performance of the catalyst is improved; by virtue of the multiparous property of the ceramic membrane, the membrane catalyst can be used for forming a circulating type catalytic membrane reactor, the problem of difficult separation of the catalyst from aproduct is avoided, and the supported catalyst can be widely applied to the circulating type catalytic reaction process.

Preparation method of supported catalyst for circulating type catalytic reaction

The invention relates to a method for treating high-concentration p-nitrophenol, and belongs to the catalysis technical field. The method realizes complete conversion of high-concentration p-nitrophenol through a flow-through reactor. The keys of the method comprise preparation of a catalytic membrane with excellent performance and construction of the flow-through reactor. Firstly, dendritic TiO2nanorods are grown on the surface of a ceramic membrane and pore channels, are modified by a silane coupling agent and then are loaded with Pd particles to prepare the catalytic membrane. The flow-through reactor is constructed with use of the porous characteristic of the membrane; a reaction liquid continuously flows through membrane pores and makes full contact with active components, reaction is performed, and thus the continuous and complete conversion of high-concentration p-nitrophenol is achieved. The method has the advantages that the dendritic TiO2 nanorods can increase the specific surface area of the membrane, so the dendritic TiO2 nanorods are loaded with more Pd particles and the catalytic activity is improved; the branching of TiO2 can play a role in fixing Pd particles; andwith the loading of the Pd particles on the surface and pore channels, the problem of difficulty of subsequent separation of the catalyst and the product is solved.

Jianfeng Miao

Papers

Continuous and complete conversion of high concentration p-nitrophenol in a flow-through membrane reactor

Pd nanoparticles immobilized on TiO2 nanotubes-functionalized ceramic membranes for flow-through catalysis

Preparation method of supported catalyst for circulating type catalytic reaction

Method for treating high-concentration p-nitrophenol