Showing papers by "Giuseppe Barbieri published in 2019"

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

Abstract: 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).

Membrane condenser as emerging technology for water recovery and gas pre-treatment: current status and perspectives

Abstract: The recent roadmap of SPIRE initiative includes the development of “new separation, extraction and pre-treatment technologies” as one of the “key actions” for boosting sustainability, enhancing the availability and quality of existing resources. Membrane condenser is an innovative technology that was recently investigated for the recovery of water vapor for waste gaseous streams, such as flue gas, biogas, cooling tower plumes, etc. Recently, it has been also proposed as pre-treatment unit for the reduction and control of contaminants in waste gaseous streams (SOx and NOx, VOCs, H2S, NH3, siloxanes, halides, particulates, organic pollutants). This perspective article reports recent progresses in the applications of the membrane condenser in the treatment of various gaseous streams for water recovery and contaminant control. After an overview of the operating principle, the membranes used, and the main results achieved, the work also proposes the role of this technology as pre-treatment stage to other separation technologies. The potentialities of the technology are also discussed aspiring to pave the way towards the development of an innovative technology where membrane condenser can cover a key role in redesigning the whole upgrading process.

Recovery of water and contaminants from cooling tower plume

Abstract: Membrane assisted condenser is an innovative membrane operation that exploits the hydrophobic nature of microporous membranes to promote water vapor condensation and recovery. It can be used for water and chemicals recovery from waste gaseous streams. In this work, the testing of membrane condenser for water and ammonia recovery from synthetic streams (i.e., a saturated air stream with ammonia) simulating the plume of cooling tower is illustrated. The modeling of the process was carried out for predicting the membrane-based process performance and for identifying the minimum operating conditions for effectively recovering liquid water. The experimental data were compared with the results achieved through the simulations showing good agreement and confirming the validity of the model. It was found that the recovery of water can be increased growing the temperature difference between the plume and the membrane module (DT), the relative humidity of the plume (RH) and the feed flow rate on membrane area ratio. Moreover, the concentration of NH3 in the recovered liquid water increased with the growing DT, at increasing NH3 concentration in the fed gaseous stream and at growing relative humidity of the feed.

Preparation and Characterisation of Photocatalysts for CO2 valorisation in Membrane Reactors

Abstract: Doctorate School in Environmental Sciences and Engineering, of Buildings and Energy (SIACE). Ciclo XXXI

Membranes containing polymerised ionic liquid for use in gas separation

Abstract: The invention relates to dense synthetic membranes made from polymerised phosphonium-based ionic liquids which were found to be particularly suitable for use in gas separation. The membranes are obtainable by copolymerization via UV-curing of a composition comprising a phosphonium-based ionic liquid monomer, a co-monomer, a cross-linker, a surfactant and a a photo-initiator, the remainder of the polymerization mixture consisting of water. The invention also relates to a process of manufacturing said membranes, resulting in solid, dense and mechanically stable membranes, and to the use of the membranes so produced in the separation of gas mixtures, particularly gas mixtures containing carbon dioxide.