Photocatalityc membrane reactor for CO2 conversion

Global warming is considered to be one of the principal environmental problems and CO2, being a greenhouse gas, largely contributes to the global climate change. Owing to this problem, an increasing concern has brought the scientific community to devote huge efforts towards CO2 reduction and/or valorization through a sustainable process. In this contest, photocatalytic membrane technologies can be a promising and innovative way to pursue CO2 conversion into value-added products.1 To this purpose, Carbon Nitride (C3N4) photocatalyst was prepared and characterized by FTIR and IR-ATR, DRS and XRD analyses. The preliminary reactivity experiments were carried out in a batch reactor (V = 120 mL) filled with humid CO2 and irradiated in a solar box (65°C). CH4 and CO were the main reduction products detected. This catalyst was then dispersed to obtain catalytic mixed matrix Nafion membranes. Comprehensive structural and morphological analyses by DRS, FT-IR, ATR-IR, SEM and N2 and CO2 permeability measurements were performed. The photocatalytic membranes were then used for the same reaction under UV-Vis irradiation in a membrane reactor operating in continuous mode, as already done with TiO2-Nafion catalytic membranes2. Different H2O/CO2 molar ratios and residence times were used. MeOH, EtOH and HCHO were the main products detected. Under the best experimental conditions, methanol and ethanol were identified as the main products with a productivity of 23 and 25 mol g-1 h-1, respectively. References. 1. R. Molinari, A. Caruso, L. Palmisano, Photocatalytic Membrane reactor in the conversion or degradation of organic compounds, in E. Drioli et L. Giorno (Eds.) Membrane Operations, innovative Separation and transformations, Chapter 15, 335-361, 2009, Wiley-Vch Verlag GmbH & Co. KGaA, Weinheim (Germany). 2. M. Sellaro, M. Bellardita, A. Brunetti, E. Fontananova, L. Palmisano, E. Drioli, G. Barbieri, “CO2 conversion in a photocatalytic continuous membrane reactor”, RSC Advances, 2016, 6, 67418 – 67427

Graphene Oxide Membranes for Reverse Electrodialysis Applications

Graphene Oxide Membranes for Reverse Electrodialysis Application

Probing membrane and interface properties in concentrated electrolyte solutions

This study deals with the membrane and interface electrical properties investigation by electrochemical impedance spectroscopy (EIS). The EIS is a powerful technique for characterizing electrical behavior of systems in which coupled electrical processes occur at different rates.A systematics tudy on the effect of solution concentration,temperature and velocity, on the electrical resistance of anion-and cation- exchange membranes (AEMs and CEMs) and their interfaces (electrical double layer and diffusion boundary layer), was carried out. At the best of our knowledge, for t he first time electrolyte concentrations up to 4 M were used for the study of membranes and interface by EIS. Moreover, Pulsed Gradient Spin Echo Nuclear Magnetic Resonance (PGSE-NMR)technique was used to measure the water self-diffusion coefficients in swelled membrane as a function of the solution concentration and temperature.These measurements gave additional important insights about the effect of the electrolyte solution and fixed charges concentration in membrane,on membrane microstructure and its transport and electrical properties. & 2014TheAuthors.PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBY This study deals with the membrane and interface electrical properties investigation by electrochemical impedance spectroscopy (EIS)

Foto-reattori a membrana per la valorizzazione del CO2

In questo lavoro è stata studiata la foto-riduzione del CO2 sotto irraggiamento con luce UV-Visibile, accoppiando per la prima volta la tecnologia del reattore continuo a membrana con l’utilizzo di catalizzatori a base di C3N4 puro o compositi C3N4-TiO2 dispersi in una matrice polimerica di Nafion

High temperature (HT) polymer electrolyte membrande fuel cells (PEMFC) - A review

One possible solution of combating issues posed by climate change is the use of the High Temperature (HT) Polymer Electrolyte Membrane (PEM) Fuel Cell (FC) in some applications. The typical HT-PEMFC operating temperatures are in the range of 100e200 o C which allows for co-generation of heat and power, high tolerance to fuel impurities and simpler system design. This paper reviews the current literature concerning the HT-PEMFC, ranging from cell materials to stack and stack testing. Only acid doped PBI membranes meet the US DOE (Department of Energy) targets for high temperature membranes operating under no humidification on both anode and cathode sides (barring the durability). This eliminates the stringent requirement for humidity however, they have many potential drawbacks including increased degradation, leaching of acid and incompatibility with current state-of-the-art fuel cell materials. In this type of fuel cell, the choice of membrane material determines the other fuel cell component material composition, for example when using an acid doped system, the flow field plate material must be carefully selected to take into account the advanced degradation. Novel research is required in all aspects of the fuel cell components in order to ensure that they meet stringent durability requirements for mobile applications.Web of Scienc

An Overview on Exploitation of Graphene-Based Membranes: From Water Treatment to Medical Industry, Including Recent Fighting against COVID-19

Graphene and its derivatives have lately been the subject of increased attention for different environmental applications of membrane technology such as water treatment and air filtration, exploiting their antimicrobial and antiviral activity. They are interesting candidates as membrane materials for their outstanding mechanical and chemical stability and for their thin two-dimensional (2D) nanostructure with potential pore engineering for advanced separation. All these applications have evolved and diversified from discovery to today, and now graphene and graphene derivatives also offer fascinating opportunities for the fight against infective diseases such as COVID-19 thanks to their antimicrobial and antiviral properties. This paper presents an overview of graphene-based 2D materials, their preparation and use as membrane material for applications in water treatment and in respiratory protection devices

Development of new polymeric functional membranes for applications in catalysis and fuel celles

Dottorato di Ricerca in Ingegneria Chimica e dei Materiali, XX Ciclo,a.a. 2006-2007Università degli Studi della Calabri

CO2 reduction by C3N4-TiO2 Nafion photocatalytic membrane reactor as a promising environmental pathway to solar fuels

We investigated CO2 photocatalytic reduction coupling, for the first time in literature, the assets offered by the continuous operating mode using C3N4-TiO2 photo-catalyst embedded in a dense Nafion matrix. The reactor performance was analyzed under UV–vis light in terms of productivity, selectivity and converted carbon. Reaction pressure was specifically investigated for its effect as a “driver” in determining reactor performance, modulating products removal from the reaction volume. In addition, the membrane reactor performance was explored as a function of H2O/CO2 feed molar ratio and contact time. The higher feed pressure (5 bar) led to a lesser MeOH production and a greater amount of HCHO, owing to a hindered desorption, which promoted partial oxidation reactions. Total converted carbon instead did not vary significantly with reaction pressure. Membrane reactor with C3N4-TiO2 photocatalyst resulted more performant than other photocatalytic membrane reactors in terms of carbon converted (61 μmol gcatalyst−1 h−1

Photocatalytic Membranes in Photocatalytic Membrane Reactors

The present work gives a critical overview of the recent progresses and new perspectives in the field of photocatalytic membranes (PMs) in photocatalytic membrane reactors (PMRs), thus highlighting the main advantages and the still existing limitations for large scale applications in the perspective of a sustainable growth. The classification of the PMRs is mainly based on the location of the photocatalyst with respect to the membranes and distinguished in: (i) PMRs with photocatalyst solubilized or suspended in solution and (ii) PMRs with photocatalyst immobilized in/on a membrane (i.e., a PM). The main factors affecting the two types of PMRs are deeply discussed. A multidisciplinary approach for the progress of research in PMs and PMRs is presented starting from selected case studies. A special attention is dedicated to PMRs employing dispersed TiO2 confined in the reactor by a membrane for wastewater treatment. Moreover, the design and development of efficient photocatalytic membranes by the heterogenization of polyoxometalates in/on polymeric membranes is discussed for applications in environmental friendly advanced oxidation processes and fine chemical synthesis