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Special Issue "Membrane Catalysis"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Bioorganic Chemistry".

Deadline for manuscript submissions: closed (20 March 2016)

Special Issue Editor

Guest Editor
Prof. Dr. Raffaele Molinari

Department of Environmental and Chemical Engineering, Università della Calabria, Rende (CS), Italy
Website | E-Mail
Interests: membrane processes; catalytic and photocatalytic membrane reactors; complexation reactions coupled with membranes (supported liquid membranes); ultrafiltration assisted by polymers; saving, recovery and recycle of matter and energy by membrane processes

Special Issue Information

Dear Colleagues,

Membrane and catalysis is a marriage of great scientific interest because, in many cases, the potentialities of membrane processes and those of catalytic processes are enhanced thanks to their synergy. Membrane Catalysis is performed in a device called Membrane Reactor (MR), where the chemical reaction and the separation process can be accomplished simultaneously in the same physical device, thus fulfilling the criteria of process intensification and minimizing environmental and economical impacts. Generally the membrane allows to confine the catalyst in the reaction ambient, thus facilitating its reuse and also permitting the selective separation of specific molecules present in the reaction ambient. As a result, a minimization of the formation of by-products, thus improving conversion, selectivity, and yield that can be obtained. Higher energy efficiency, modularity, and easy scale up are some other advantages of Membrane Catalysis compared to convectional catalysis. The appropriate choice of the membrane type, membrane module configuration, and MR is mainly determined by the type of catalysis (e.g.: homogeneous, heterogeneous, photo, bio) where the membrane can assume many roles as catalyst recovery, separation of the products, rejection of the substrate, etc. In this Special Issue, some of the most recent advances in Membrane Catalysis of basic interest or relevant to current industrial processes or processes under development or of interest for future applications, will be provided to disseminate the latest information for application in various fields.

Prof. Dr. Raffaele Molinari
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • homogeneous membrane catalysis
  • heterogeneous membrane catalysis
  • membrane photocatalysis
  • membrane biocatalysis
  • membrane enzyme catalysis
  • membrane phase-transfer catalysis
  • membrane nanoparticles catalysis
  • membrane catalysis for waste water purification
  • membrane catalysis for product synthesis
  • membrane catalysis for partial oxidations
  • membrane catalysis for process intensification
  • membrane catalysis for environmental applications

Published Papers (7 papers)

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Editorial

Jump to: Research

Open AccessEditorial Special Issue “Membrane Catalysis”
Molecules 2016, 21(7), 851; doi:10.3390/molecules21070851
Received: 21 June 2016 / Accepted: 22 June 2016 / Published: 28 June 2016
PDF Full-text (137 KB) | HTML Full-text | XML Full-text
Abstract
Membrane technology is recognized as a scientific sector of multidisciplinary interest.[...] Full article
(This article belongs to the Special Issue Membrane Catalysis)

Research

Jump to: Editorial

Open AccessArticle Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents
Molecules 2016, 21(6), 668; doi:10.3390/molecules21060668
Received: 18 March 2016 / Revised: 29 April 2016 / Accepted: 13 May 2016 / Published: 24 May 2016
Cited by 1 | PDF Full-text (5191 KB) | HTML Full-text | XML Full-text
Abstract
We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO) reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde
[...] Read more.
We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO) reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation methods do not work for formaldehyde, a highly toxic but refractory, low biodegradability substance. The CWO reaction is a recent, promising alternative that also permits much lower temperature and pressure conditions than other oxidation processes, resulting in economic benefits. The CWO reaction employing Ce- and Co-containing catalysts was carried out inside a slurry batch reactor and a membrane reactor. Experimental results are reported. Next, a mixed Ce–Co oxide film was supported on an γ-alumina membrane used in a catalytic membrane reactor to compare formaldehyde removal between both types of systems. Catalytic materials with cerium and with a relatively large amount of cerium favored the transformation of formaldehyde. Cerium was present as cerianite in the catalytic materials, as indicated by X-ray diffraction patterns. Full article
(This article belongs to the Special Issue Membrane Catalysis)
Open AccessArticle Supported Pd-Au Membrane Reactor for Hydrogen Production: Membrane Preparation, Characterization and Testing
Molecules 2016, 21(5), 581; doi:10.3390/molecules21050581
Received: 16 March 2016 / Revised: 20 April 2016 / Accepted: 22 April 2016 / Published: 9 May 2016
Cited by 9 | PDF Full-text (2739 KB) | HTML Full-text | XML Full-text
Abstract
A supported Pd-Au (Au 7wt%) membrane was produced by electroless plating deposition. Permeation tests were performed with pure gas (H2, H2, N2, CO2, CH4) for long time operation. After around 400 h under
[...] Read more.
A supported Pd-Au (Au 7wt%) membrane was produced by electroless plating deposition. Permeation tests were performed with pure gas (H2, H2, N2, CO2, CH4) for long time operation. After around 400 h under testing, the composite Pd-Au membrane achieved steady state condition, with an H2/N2 ideal selectivity of around 500 at 420 °C and 50 kPa as transmembrane pressure, remaining stable up to 1100 h under operation. Afterwards, the membrane was allocated in a membrane reactor module for methane steam reforming reaction tests. As a preliminary application, at 420 °C, 300 kPa of reaction pressure, space velocity of 4100 h−1, 40% methane conversion and 35% hydrogen recovery were reached using a commercial Ni/Al2O3 catalyst. Unfortunately, a severe coke deposition affected irreversibly the composite membrane, determining the loss of the hydrogen permeation characteristics of the supported Pd-Au membrane. Full article
(This article belongs to the Special Issue Membrane Catalysis)
Open AccessArticle Preparation of Pd-Loaded Hierarchical FAU Membranes and Testing in Acetophenone Hydrogenation
Molecules 2016, 21(3), 394; doi:10.3390/molecules21030394
Received: 9 February 2016 / Revised: 17 March 2016 / Accepted: 18 March 2016 / Published: 22 March 2016
Cited by 3 | PDF Full-text (3341 KB) | HTML Full-text | XML Full-text
Abstract
Pd-loaded hierarchical FAU (Pd-FAU) membranes, containing an intrinsic secondary non-zeolitic (meso)porosity, were prepared and tested in the catalytic transfer hydrogenation of acetophenone (AP) to produce phenylethanol (PE), an industrially relevant product. The best operating conditions were preliminarily identified by testing different solvents and
[...] Read more.
Pd-loaded hierarchical FAU (Pd-FAU) membranes, containing an intrinsic secondary non-zeolitic (meso)porosity, were prepared and tested in the catalytic transfer hydrogenation of acetophenone (AP) to produce phenylethanol (PE), an industrially relevant product. The best operating conditions were preliminarily identified by testing different solvents and organic hydrogen donors in a batch hydrogenation process where micron-sized FAU seeds were employed as catalyst support. Water as solvent and formic acid as hydrogen source resulted to be the best choice in terms of conversion for the catalytic hydrogenation of AP, providing the basis for the design of a green and sustainable process. The best experimental conditions were selected and applied to the Pd-loaded FAU membrane finding enhanced catalytic performance such as a five-fold higher productivity than with the unsupported Pd-FAU crystals (11.0 vs. 2.2 mgproduct gcat−1·h−1). The catalytic performance of the membrane on the alumina support was also tested in a tangential flow system obtaining a productivity higher than that of the batch system (22.0 vs. 11.0 mgproduct gcat−1·h−1). Full article
(This article belongs to the Special Issue Membrane Catalysis)
Figures

Open AccessArticle Fluidized Bed Membrane Reactors for Ultra Pure H2 Production—A Step forward towards Commercialization
Molecules 2016, 21(3), 376; doi:10.3390/molecules21030376
Received: 3 February 2016 / Revised: 8 March 2016 / Accepted: 9 March 2016 / Published: 19 March 2016
Cited by 12 | PDF Full-text (7693 KB) | HTML Full-text | XML Full-text
Abstract
In this research the performance of a fluidized bed membrane reactor for high temperature water gas shift and its long term stability was investigated to provide a proof-of-concept of the new system at lab scale. A demonstration unit with a capacity of 1
[...] Read more.
In this research the performance of a fluidized bed membrane reactor for high temperature water gas shift and its long term stability was investigated to provide a proof-of-concept of the new system at lab scale. A demonstration unit with a capacity of 1 Nm3/h of ultra-pure H2 was designed, built and operated over 900 h of continuous work. Firstly, the performance of the membranes were investigated at different inlet gas compositions and at different temperatures and H2 partial pressure differences. The membranes showed very high H2 fluxes (3.89 × 10−6 mol·m−2·Pa−1·s−1 at 400 °C and 1 atm pressure difference) with a H2/N2 ideal perm-selectivity (up to 21,000 when integrating five membranes in the module) beyond the DOE 2015 targets. Monitoring the performance of the membranes and the reactor confirmed a very stable performance of the unit for continuous high temperature water gas shift under bubbling fluidization conditions. Several experiments were carried out at different temperatures, pressures and various inlet compositions to determine the optimum operating window for the reactor. The obtained results showed high hydrogen recovery factors, and very low CO concentrations at the permeate side (in average <10 ppm), so that the produced hydrogen can be directly fed to a low temperature PEM fuel cell. Full article
(This article belongs to the Special Issue Membrane Catalysis)
Figures

Open AccessArticle Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor
Molecules 2016, 21(3), 345; doi:10.3390/molecules21030345
Received: 26 January 2016 / Revised: 3 March 2016 / Accepted: 8 March 2016 / Published: 14 March 2016
Cited by 2 | PDF Full-text (2125 KB) | HTML Full-text | XML Full-text
Abstract
Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use
[...] Read more.
Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic hollow fibre membranes and their use in a two-separate-phase biocatalytic membrane reactor will be described. The asymmetric ceramic hollow fibre membranes were prepared using a combined phase inversion and sintering technique. The prepared fibres were then used as support for lipase covalent immobilization in order to develop a two-separate-phase biocatalytic membrane reactor. A functionalization method was proposed in order to increase the density of the reactive hydroxyl groups on the surface of ceramic membranes, which were then amino-activated and treated with a crosslinker. The performance and the stability of the immobilized lipase were investigated as a function of the amount of the immobilized biocatalytst. Results showed that it is possible to immobilize lipase on a ceramic membrane without altering its catalytic performance (initial residual specific activity 93%), which remains constant after 6 reaction cycles. Full article
(This article belongs to the Special Issue Membrane Catalysis)
Open AccessArticle Morphology and N2 Permeance of Sputtered Pd-Ag Ultra-Thin Film Membranes
Molecules 2016, 21(2), 210; doi:10.3390/molecules21020210
Received: 23 December 2015 / Revised: 25 January 2016 / Accepted: 2 February 2016 / Published: 10 February 2016
Cited by 3 | PDF Full-text (2254 KB) | HTML Full-text | XML Full-text
Abstract
The influence of the temperature during the growth of Pd-Ag films by PVD magnetron sputtering onto polished silicon wafers was studied in order to avoid the effect of the support roughness on the layer growth. The surfaces of the Pd-Ag membrane films were
[...] Read more.
The influence of the temperature during the growth of Pd-Ag films by PVD magnetron sputtering onto polished silicon wafers was studied in order to avoid the effect of the support roughness on the layer growth. The surfaces of the Pd-Ag membrane films were analyzed by atomic force microscopy (AFM), and the results indicate an increase of the grain size from 120 to 250–270 nm and film surface roughness from 4–5 to 10–12 nm when increasing the temperature from around 360–510 K. After selecting the conditions for obtaining the smallest grain size onto silicon wafer, thin Pd-Ag (0.5–2-µm thick) films were deposited onto different types of porous supports to study the influence of the porous support, layer thickness and target power on the selective layer microstructure and membrane properties. The Pd-Ag layers deposited onto ZrO2 3-nm top layer supports (smallest pore size among all tested) present high N2 permeance in the order of 10−6 mol·m−2·s−1·Pa−1 at room temperature. Full article
(This article belongs to the Special Issue Membrane Catalysis)

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Fluidized Bed Membrane Reactors for Ultra Pure H2 Production - a Step Forward Towards Commercialization
Authors:
Arash Helmi 1, Ekain Fernandez 1,2, Alfredo Pacheco Tanaka 2, Martin van Sint Annaland 1, Fausto Gallucci1 *
Affiliation:
1 Chemical Process Intensification, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5612 AZ Eindhoven, The Netherlands
2
TECNALIA, Energy and Environment Division, Mikeletegi Pasealekua 2, 20009 San Sebastián-Donostia, Spain
Abstract:
A demonstration unit for hydrogen production via WGS reaction has been designed built and operated for up to 900 hr showing high hydrogen recovery factors, and very low CO concentrations in the permeate side. The produced hydrogen can be directly fed to a PEM FC.

Title: A Dialysis Application in a Photocatalytic Membrane Reactor
Authors:
G.Camera-Roda, V.Loddo, L.Palmisano, F.Parrino.
Affiliation:
Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Italy
Abstract:
The recovery of the valuable intermediate product of reactions in series by a membrane process may avoid the degradation of the product and consequently substantially enhances the yield. This result is obtained only if the dialysis process and the reaction take place concurrently in a so called "integrated process". The photocatalytic reaction here considered produces vanillin by partial oxidation of ferulic acid in a green process. Vanillin is very effectively recovered by dialysis with a non porous poly-ether block amide membrane, thus avoiding its degradation by further oxidation. In fact, the permeation flux of vanillin is much higher than the one obtained with pervaporation. However, also some undesirable behaviors are observed. In fact, also the reagent permeates and concentration polarization limits the permeation rate. The analysis of the experimental results by a mathematical model allows the identification of the procedures, which minimizes these negative effects.

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