In situ restoring of aged thermally rearranged gas separation membranes

Brunetti, Adele,Cersosimo, Maurizio,Dong, Guangxi,Woo, Kyung Take,Lee, Jongmyeong,Kim, Ju Sung,Lee, Young Moo,Drioli, Enrico,Barbieri, Giuseppe Elsevier 2016 Journal of membrane science Vol.520 No.-

<P><B>Abstract</B></P> <P>Physical aging in high free-volume polymer membranes is one of the main hurdles limiting their application in gas separation. The recovery of membrane separation properties without the need to disassemble the module, although challenging, would provide significant advantages for applications in various fields. In this work, an in situ restoring procedure for the recovery of mass transport in aged membrane modules made of thermally rearranged polymer membranes was developed in which the modules were exposed to methanol at 80°C. The thermally rearranged hollow fiber membrane modules were subjected to long-time operation to investigate their aging: the CO<SUB>2</SUB> and N<SUB>2</SUB> permeances were monitored at different temperatures, pressures, and feed compositions over a total period of 727 days with two long-time runs of 185 and 263 days, interspersed by a stand-by period of 240 days, and with each run followed by a restoring. In both long-time runs, CO<SUB>2</SUB> and N<SUB>2</SUB> permeance dropped as a result of aging, whereas the selectivity remained nearly constant. The permeances were fully recovered after the proposed restoring procedure was applied, demonstrating its efficacy and repeatability for membrane aging recovery, even for an extremely aged membrane exposed to various conditions for nearly two years.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In-situ restoring of mass transport in aged membranes. </LI> <LI> Thermally rearranged polymer membranes. </LI> <LI> Periodic measures over years on thermally rearranged polymer membranes. </LI> <LI> Repeatability of in-situ restoring showing full permeation properties recovery. </LI> </UL> </P>

Membrane engineering for environmental protection and sustainable industrial growth: Options for water and gas treatment

Adele Brunetti,Francesca Macedonio,Giuseppe Barbieri,Enrico Drioli 대한환경공학회 2015 Environmental Engineering Research Vol.20 No.4

The increasing demand for materials, energy and products drives chemical engineers to propose new solutions everyday able to promote development while supporting sustainable industrial growth. Membrane engineering can offer significant assets to this development. Here, they are identified the most interesting aspects of membrane engineering in strategic industrial sectors such as water treatment, energy production and depletion and reuse of raw materials. The opportunity to integrate membrane units with innovative systems to exploit the potential advantages derived from their synergic uses is also emphasized. The analysis of the potentialities of these new technologies is supported by the introduction of process intensification metrics which provide an alternative and innovative point of view regarding the unit performance, highlighting important aspects characterizing the technology and not identified by the conventional analysis of the unit performance.

Thermally rearranged mixed matrix membranes for CO₂ separation: An aging study

Brunetti, Adele,Cersosimo, Maurizio,Kim, Ju Sung,Dong, Guangxi,Fontananova, Enrica,Lee, Young Moo,Drioli, Enrico,Barbieri, Giuseppe Elsevier 2017 INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol.61 No.-

<P><B>Abstract</B></P> <P>In this work, the aging behavior of a thermally rearranged polybenzoxazole-co-imide (TR-PBOI) mixed matrix membrane loaded with 0.5wt.% of oxidized multi-wall carbon nanotubes (MWCNT) was evaluated and then compared to a pure TR polymeric membrane prepared from the same precursor. To the best of authors knowledge, this is the first report of a mixed matrix membrane being prepared through the dispersion of MWCNTs within a thermally rearranged polymer matrix for CO<SUB>2</SUB> separation. Microporous structures were created in both membranes when thermally rearranged at 375°C, facilitating fast mass transfer ideal for membrane gas separation. The TR mixed matrix membrane with oxidized CNTs demonstrated improved separation properties with regard to both permeability and selectivity compared to the pure TR polymeric membrane due to a greater degree of thermal rearrangement (11.3%) than what was exhibited by the TR membrane (6.7%). Moreover, the high CO<SUB>2</SUB> solubility typical of TR polymers coupled with diffusivity enhancements improved the CO<SUB>2</SUB>/N<SUB>2</SUB> selectivity. The addition of oxidized CNTs to the TR-PBOI polymer did not significantly influence the aging behavior of the mixed matrix membrane. Both pure TR-PBOI and mixed matrix membranes exhibited an increase in CO<SUB>2</SUB> selectivity due to physical aging. The improved separation properties in conjunction with an unchanged membrane stability over time suggested that the addition of CNTs to pure TR membranes could be an excellent approach toward improving the performance of thermally rearranged membranes applied toward gas separation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Separation properties of a pure TR and a TR+CNTs mixed matrix membranes. </LI> <LI> Aging behavior of a pure TR and a TR+CNTs mixed matrix membranes. </LI> <LI> No significant difference observed in aging behavior of TR+CNT membrane with respect to pure TR membrane. </LI> <LI> TR+CNTs mixed matrix membrane more permeable and selective than pure TR membrane. </LI> </UL> </P>

Process intensification strategies and membrane engineering

Drioli, Enrico,Brunetti, Adele,Di Profio, Gianluca,Barbieri, Giuseppe The Royal Society of Chemistry 2012 Green chemistry Vol.14 No.6

<P>An important contribution to the realization of industrial sustainable development can be given by “green process engineering”. Based on the principles of the Process intensification strategy it can lead to the development and the re-design of new processes more compact and efficient that allow the better exploitation of raw materials, a lower energy consumption and a reduced plant volume. Membrane technology contributes to the pursuit of these principles and, in the last few years, the potentialities of membrane operations have been widely recognized. In this work, an overview of membrane application and their perspectives in the field of hydrogen production and distillation will be analysed considering membrane reactors and membrane distillation as case studies. The scope is to show how the redesign as membrane systems of traditional operations might contribute to the realization of the goals of process intensification and green chemistry by a new “green process engineering”.</P> <P>Graphic Abstract</P><P>Green chemistry and green process engineering also mean new processes such as those based on membrane reactors and membrane contactors. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2gc16668b'> </P>

Recovery of water and contaminants from cooling tower plume

Francesca Macedonio,Mirko Frappa,Adele Brunetti,Giuseppe Barbieri,Enrico Drioli 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.2

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<SUP>plume</SUP>) 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.

Sorption and Diffusion of CO₂/N₂ in gas mixture in thermally-rearranged polymeric membranes: A molecular investigation

Rizzuto, Carmen,Caravella, Alessio,Brunetti, Adele,Park, Chi Hoon,Lee, Young Moo,Drioli, Enrico,Barbieri, Giuseppe,Tocci, Elena Elsevier 2017 Journal of membrane science Vol.528 No.-

<P><B>Abstract</B></P> <P>In this work, we study the adsorption and diffusion of nitrogen and carbon dioxide through an atomistically detailed model of a thermally rearranged polybenzoxazole (TR-PBO) polymer membranes, <I>via</I> equilibrium molecular dynamics (MD) simulations. This work represents a first explicit molecular modelling of the behavior of CO<SUB>2</SUB>/N<SUB>2</SUB> binary mixture in TR-PBO and demonstrates how diffusivity and solubility in mixtures can be coherently obtained. In particular, the number of molecules present in the polymer matrix is estimated using the Gran Canonical Monte Carlo approach. As for the sorption in mixture conditions, MD simulations are used in a synergistic pairing with GCMC and Ideal Adsorption Solution Theory (IAST). For this purpose, the single-gas isotherms calculated from GCMC simulations are fitted with Langmuir and Dual-Langmuir adsorption models to obtain the parameters needed for the IAST simulations.</P> <P>As for diffusion, single-gas and mixture (Maxwell-Stefan) diffusion coefficients are performed by MD simulations. As main results, it is observed that the evaluated diffusion coefficients of CO<SUB>2</SUB> and N<SUB>2</SUB> are in a satisfactory agreement with the values estimated using the available experimental permeability data. More specifically, the CO<SUB>2</SUB> diffusivity in mixture conditions is found to be the same as that in the single-gas one, whereas the N<SUB>2</SUB> diffusivity is slightly higher. These differences are explained in terms of the effect of both the mutual gas diffusion and the competing occupancy of the available free space preferentially occupied by the CO<SUB>2</SUB> molecules in mixture.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sorption of gas mixture are characterized by the Monte-Carlo method and IAST. </LI> <LI> The Maxwell-Stefan diffusivities are calculated by molecular dynamics simulations. </LI> <LI> The N<SUB>2</SUB> diffusivity in mixture slightly increases with respect to the single-gas case. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>