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Mauro Dal-Cin

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Papers by Mauro Dal-Cin

CFD-assisted thin channel membrane characterization module design

Journal of Membrane Science, Feb 1, 1997

This project involved the design of a thin channel cross-flow module for the characterization of ... more This project involved the design of a thin channel cross-flow module for the characterization of flat ceramic membranes. A primary objective of this work was to ensure that the flow characteristics over the permeating area were uniform. To house these membranes, a thin channel module with a long rectangular base was envisioned. The module feed is supplied by a multi-inlet tube-type plenum meant to provide a uniform flow distribution through pressure equilibration attained in its volume. The design criteria for the module were minimization of both the flow non-uniformity and the pressure drop across the permeating area which was a central rectangular portion of a larger slab-style cell. The flow non-uniformity was taken as the normalized standard deviation of the velocity field above the permeating area. The pressure drops considered were those across the inlet plenum and across the permeating area normalized with respect to the outlet pressure. The computational fluid dynamics (CFD) scheme which calculated the above module characteristics was a k-e based turbulent transport model which used the finite difference method. Design variables considered were: the plenum diameter, module width, height and length, and the diameters, distribution and number of the inlets on the plenum. The distribution of the inlet diameters was determined by two variables: either a linear or parabolic profile of variable slope and model coefficient. The operating variables were the cross-flow velocity and the plenum inlet pressure. A two-level factorial design was used to screen the design variables. A refined three-level factorial design was used with a reduced set of design variables to optimize the module and study the response surface. The final module design parameters were chosen such that the design criteria of flow uniformity and low pressure drop were met under a preset range of operating conditions. The local gradients of the response surface were used to verify that the design criteria were not overly sensitive to the selected module design parameters.

Extraction of Cobalt and Nickel from a Pyrrhotite Rich Tailings Sample via Bioleaching

The Minerals, Metals & Materials Series, 2018

The growing use and acceptance of electric vehicles (EV), as evidenced by the record sales of ove... more The growing use and acceptance of electric vehicles (EV), as evidenced by the record sales of over 750 thousand vehicles in 2016 and a current global EV stock of 2 million vehicles, is putting pressure on sourcing raw materials such as cobalt, and to a lesser extent, nickel. Global supply is poorly diversified, with 50–60% of global cobalt production sourced solely from the Democratic Republic of Congo (DRC). One potential source for cobalt and nickel are low-grade nickeliferous pyrrhotite tailings, of which 50–100 million tonnes are present in the Sudbury area alone. This paper presents the extraction of cobalt and nickel from this material using a combination of flotation and bioleaching technologies. The findings of a high-level techno-economic analysis of the proposed processing flowsheet are presented.

Polymer nanosieve membranes for CO2-capture applications

Nature Materials, 2011

Microporous organic polymers (MOPs) are of potential technological significance for gas storage 1... more Microporous organic polymers (MOPs) are of potential technological significance for gas storage 1-3 , gas separation 4 and low-dielectric applications 5. Among many approaches for obtaining such materials, solution-processable MOPs derived from rigid and contorted macromolecular structures are promising because of their excellent mass transport and mass exchange capability. Here we show a class of amorphous MOP, prepared by [2 + 3] cycloaddition modification of a polymer containing an aromatic nitrile group with an azide compound, showing super-permeable characteristics and outstanding CO 2 separation performance, even under polymer plasticization conditions such as CO 2 /light gas mixtures. This unprecedented result arises from the introduction of tetrazole groups into highly microporous polymeric frameworks, leading to more favourable CO 2 sorption with superior affinity in gas mixtures, and selective CO 2 transport by presorbed CO 2 molecules that limit access by other light gas molecules. This strategy provides a direction in the design of MOP membrane materials for economic CO 2 capture processes. MOPs are of great interest because they combine the processability of polymers with porous materials having high surface areas (300-1,500 m 2 g −1) comparable to typical microporous solids such as zeolites and activated carbons 6-8. MOPs can be classified either as amorphous polymers (for example, substituted polyacetylenes 9 , thermally rearranged (TR) polymers 4,10 , and polymers of intrinsic microporosity (PIMs; refs 3,11)) or as crystalline polymers 12,13 (for example, covalent organic frameworks). Depending on the cavity size and shape, surface area and regularity, MOPs can be tailored for versatile applications. For membrane-based gas separation, solution-processable, amorphous MOPs are required for practical membrane fabrication such as thin-film composites. Among MOPs, poly(1-trimethylsilyl-1-propyne) (PTMSP) is known as the highest gas-permeable polymer. However, PTMSP shows low gas selectivity (for example, CO 2 /N 2 = 5.4 and CO 2 /CH 4 = 2.1; ref. 9), and also suffers from fast physical ageing, leading to a catastrophic reduction in gas permeability, because the initially formed microporous structures are rapidly corrupted by equilibrium processes. Recently, PIMs have attracted keen interest because they exhibit relatively slow physical ageing, good solubility, high gas permeability, as well as high selectivity 11,14-17 compared to PTMSP, resulting in gas separation performance that defines the upper bound of common organic polymers 18. In general, PIMs have a structural combination of rigid ladder-like backbones with sites of contortion, which prevent intra-and/or inter-chain packing and create large free-volume elements. Accordingly, it is desirable to expand the structural variety of PIMs to better understand the

Tangential flow streaming potential measurements: Hydrodynamic cell characterization and zeta potentials of carboxylated polysulfone membranes

Journal of Membrane Science, 1998

Computational¯uid dynamics calculations were carried out to ensure that a self-made tangential¯ow... more Computational¯uid dynamics calculations were carried out to ensure that a self-made tangential¯ow mode streaming potential measurement cell meets the hydrodynamic stipulations of laminar, steady and established electrolyte¯ow necessary for reproducible electrokinetic measurements. The calculations show that the cell design meets all of these conditions. Six carboxylated polysulfones with a range of different degrees of substitution (DS) from 0.26 to 1.74 carboxyl groups per polymer repeat unit were synthesized in a two-stage process of lithiation and carboxylation. Ultra®ltration membranes were made from both the unmodi®ed polysulfone and these hydrophilic materials. The zeta potentials of these membrane surfaces were determined in 0.001 M KCl solution as a function of pH. The curves show the theoretically expected pro®les for nonionic and weakly acidic materials. The growing in¯uence of the COOH dissociation on the surface charge formation is indicated by the¯attening of the curves at low pH values. The magnitude of the negative zeta potentials plateau values ranged from À52 to À20 mV. While unmodi®ed PSU has a plateau value of À52 mV this value decreases continuously with increasing DS to À20 mV for the PSU-COOH 1.74 material. It is suggested that this arises from a shift of the electrokinetic shear plane into the bulk electrolyte solution due to an extended swelling layer re¯ecting the enhanced hydrophilicity of these membrane surfaces.

Polysulfone membranes. IV. Performance evaluation of Radel A/PVP membranes

Journal of Membrane Science, 1993

Nuclear magnetic resonance (NMR) spectroscopic measurements were used to show that Radel Al00 is ... more Nuclear magnetic resonance (NMR) spectroscopic measurements were used to show that Radel Al00 is a copolymer containingpolyethersulfone and polyetherethersulfone repeat units. Membranes were cast from solutions of Radel A and polyvinylpyrrolidone (PVP) polymers dissolved in I-methyl-2-pyrrolidinone (NMP). The variation in membrane pore size is related to the casting solution composition and viscosity. The performance of Radel A/PVP membranes is compared to those of commercially available polysulfone membranes.

Membrane mass transport modeling with the periodic boundary condition

Computers & Chemical Engineering, 2009

A two-dimensional simulation of membrane permeation and separation in laminar cross-flow configur... more A two-dimensional simulation of membrane permeation and separation in laminar cross-flow configuration has been developed for cases with the periodic boundary condition (PBC) applied at the upstream (inlet) and downstream (outlet) faces of a repeating flow domain. The periodic boundary condition was applied through decoupled contributions of both solvent and solute fluxes. The upstream boundary conditions were scaled from the

A Technology Development Matrix for Carbon Capture: Technology Status and R&D Gap Assessment

Frontiers in Energy Research

Numerous carbon capture, utilization, and storage (CCUS) technologies are under development to re... more Numerous carbon capture, utilization, and storage (CCUS) technologies are under development to reduce CO2 emissions. To evaluate the status of a CCUS technology under development and identify potential gaps for further advancement, we have established a new technology assessment framework and are developing a decision-making tool, the technology development matrix (TDM), starting with available carbon capture technology (CCT) data. TDM is a data inventory system and screening tool. As a screening tool, it can be used for resource allocation decisions in research, development, and deployment (RD&D) by academia, government, and industry. It shares data with techno-economic analysis (TEA) and life-cycle assessment (LCA) tools as an inventory system. By using available data, this TDM framework has been demonstrated on amine-based (monoethanolamine) absorption post-combustion CO2 capture, for pulverized coal (PC) power plant flue gas, as the best available technology (BAT) for comparison...

Neodymium(III) and Lanthanum(III) Separation by a Flat-Sheet Supported Liquid Membrane System

Springer eBooks, 2023

Separation of Neodymium (III) and Lanthanum (III) via a Flat Sheet-Supported Liquid Membrane with Different Extractant-Acid Systems

Membranes

The increasing demand for neodymium (Nd) permanent magnets in electric motors has revived researc... more The increasing demand for neodymium (Nd) permanent magnets in electric motors has revived research interest of Nd recovery and separation from other rare earth elements (REEs). Typically, Nd/La separation is necessary for Nd recovery from primary ores and secondary resource recycling. This research used a flat sheet-supported liquid membrane (FSSLM) with different extractant-acid systems to extract Nd from a Nd/La mixture. The recovery and separation of Nd/La with 204P-H2SO4, 507P-HCl, and TBP-HNO3 were discussed. The results showed effective Nd recovery and promising Nd/La selectivity could be achieved in the 507P-HCl system, compared to 204P-H2SO4 and TBP-HNO3. The addition of citric acid to the feed solution was effective for pH buffering but did not improve the Nd transport or Nd/La selectivity. Long-term stability of the 507P-HCl extractant system was demonstrated by extending the processing time from 6 h to 6 days.

Efficient Separation of Nd(III) and La(III) Via Supported Liquid Membrane Using EHEHPA (P507) as a Carrier

Journal of Sustainable Metallurgy

This work tested an effective and efficient Nd/La extraction and separation via flat-sheet suppor... more This work tested an effective and efficient Nd/La extraction and separation via flat-sheet supported liquid membrane. A microporous polypropylene film was used as the solid support for the liquid membrane and P507 as the extractant. The effect of Nd(III) and La(III) concentration in the feed, the concentration of P507, and acid solution concentration in the stripping phase on Nd and La extraction and separation were studied. The results suggest the extraction of La and Nd increases with the initial pH of the feed solution and P507 concentration. Maximum separation factor of 44.25 was obtained at the low P507 concentration of 5% (v/v). Graphical Abstract

Effect of incorporating different ZIF-8 crystal sizes in the polymer of intrinsic microporosity, PIM-1, for CO2/CH4 separation

Microporous and Mesoporous Materials, 2021

Effective and economical carbon dioxide-methane separation (CO 2 /CH 4) is highly desirable in se... more Effective and economical carbon dioxide-methane separation (CO 2 /CH 4) is highly desirable in several industries such as sweetening natural gases and renewable natural gas (RNG) from biogas and landfills. Among the different separation technologies, membrane separation has been shown to have lower cost of production and lower CH 4 losses. In this study, Zeolitic Imidazole Frameworks (ZIF-8) crystals with sizes varying from 45 nm to 450 nm were synthesized and incorporated in the polymer of intrinsic microporosity, PIM-1, to form mixed matrix membranes (MMMs). The structure, morphology, and physicochemical properties of the MMMs were characterized by 1 H NMR, FTIR, XRD, TGA, and SEM. ZIF-8 crystal size was controlled using the concentration of sodium formate. The influence of the ZIF-8 crystal size on MMMs was studied by sorption, gas permeability, and aging of the membranes. The MMMs with ZIF-8 crystals of 120 nm particle diameter yielded the greatest improvement in gas transport properties; the CO 2 /CH 4 selectivity-CO 2 permeability was 11.4 and 9700 Barrer compared to PIM-1 with 6.4 and 9300 Barrer respectively. The former is near the Robeson 2008 upper bound, while PIM-1 is on the 1991 upper bound. After 40 days of aging, selectivity increased and permeability decreased; the changes were parallel to the Robeson upper bounds indicating increased polymer packing and diffusivity selectivity.

Gas Transport in a Polymer of Intrinsic Microporosity (PIM-1) Substituted with Pseudo-Ionic Liquid Tetrazole-Type Structures

Macromolecules, 2020

We report a side group modification strategy to tailor the structure of a polymer of intrinsic mi... more We report a side group modification strategy to tailor the structure of a polymer of intrinsic microporosity (PIM-1). PIM-1 with an average of ∼50% of the repeat units converted to tetrazole is prepared, and a subsequent reaction then introduces three types of pseudo-ionic liquid tetrazole-like structures (PIM-1-ILx). The presence of pseudo-ionic liquid functional groups in the PIM-1 structure increases gas selectivities for O 2 /N 2 and CO 2 /N 2 , while it decreases pure-gas permeabilities. The overall gas separation performance of PIM-1-ILx is close to the 2008 Robeson upper bound. Since the tetrazoles are versatile groups for building a wide variety of ionic liquids, the modification method can be expanded to explore a broad spectrum of functional groups.

Polymers of intrinsic microporosity (PIMs) substituted with methyl tetrazole

Polymer, 2012

A polymer of intrinsic microporosity (PIM-1) containing nitrile groups was reacted by [2 + 3] cyc... more A polymer of intrinsic microporosity (PIM-1) containing nitrile groups was reacted by [2 + 3] cycloaddition reaction to give a polymer substituted with tetrazole groups (TZ-PIM), and then was further methylated to give a new PIM substituted with methyl tetrazole groups (MTZ-PIM). In contrast to TZ-PIMs, the MTZ-PIMs had distinctly improved solubility characteristics, enabling a more detailed investigation of the degree of conversion for the cycloaddition reaction and the structures of TZ-PIMs, which showed the presence of two kinds of tetrazole rings. Compared with PIM-1, the MTZ-PIM showed higher gas permselectivity with a corresponding decrease in gas permeability for pure gas pairs such as O 2 /N 2 and CO 2 /N 2 , and for mixed gases, such as CO 2 /N 2. Data for selectivity coupled with high gas permeability is close to the Robeson 2008 upper-bound performance limit for the O 2 /N 2 and CO 2 /N 2 pure gas pairs, and exceeds the upper-bound for the CO 2 /N 2 mixed gas pair.

Decarboxylation-Induced Cross-Linking of Polymers of Intrinsic Microporosity (PIMs) for Membrane Gas Separation

Macromolecules, 2012

Cross-linked membranes for gas separation have been prepared by thermal treatment of carboxylated... more Cross-linked membranes for gas separation have been prepared by thermal treatment of carboxylated polymers of intrinsic microporosity (C-PIMs). The optimal cross-linking temperature was investigated and possible cross-linking pathways involving aryl radical-induced thermal decarboxylation are provided, while several other possible mechanisms are ruled out. Carboxylated PIMs are accessible by controlled hydrolysis of the nitrile-containing parent polymer. The resulting cross-linked PIMs were insoluble in typical solvents and were characterized by Fourier transform infrared spectroscopy (FTIR), TGA-MS, TGA-FTIR, and gel content analysis. The decarboxylated PIM (DC-PIM) membranes showed higher selectivities for the O 2 /N 2 ,CO 2 /N 2 , and CO 2 /CH 4 gas pairs, with evidence of suppression of swelling-induced densification under high CO 2 pressure.

Comparison of CFD and one-dimensional Bernoulli solutions of the flow in a plate and frame ultrafiltration module in Z configuration

Journal of Membrane Science, 2006

Predictions of flow and pressure distributions in one bank of a plate and frame ultrafiltration m... more Predictions of flow and pressure distributions in one bank of a plate and frame ultrafiltration module with five channels in parallel operating in a Z configuration were predicted using (1) Bernoulli's equation and a momentum balance in one dimension and (2) a threedimensional field solution (Computational Fluid Dynamics) of the Navier-Stokes equation. CFD solutions were taken as the benchmark and used to refine the 1D model being developed to evaluate flow and pressure distributions for different operating conditions and ultimately different module configurations. The 1D model was able to provide quantitatively accurate flow distribution and qualitatively representative pressure distributions. Flow distributions increased monotonically with increasing channel number, maximum/minimum flow ratios in channels increased from 2 to 6.9 with oil (µ = 0.0361 kg/m/s) as the design cross flow velocity increased from 0.5 to 5 m/s. Pressure distributions were well predicted qualitatively but were typically 40% lower than the CFD solution in the distributor. Key to the accuracy of the 1D model were the implementation of (a) variable contraction coefficients in the distributor orifice, (b) the 1/7th power law for velocity profiles in the plenums (c) a new approach for combining flows in the collector and (d) assuming only one half of the orifice area was being effectively used by the fluid.

Gas separation transport modeling for PDMS coatings on PEI-PEG IPN membranes

Journal of Membrane Science, 2010

A caulking layer is frequently applied to gas separation membranes to alleviate the effects of st... more A caulking layer is frequently applied to gas separation membranes to alleviate the effects of structural defects. Caulking materials have high gas diffusivities, so as not to hinder the performance of the gas separation layer. Despite these considerations, for some bi-layer systems unaffected by plasticization, the mixed gas selectivity has been observed to be significantly lower than selectivity values calculated from pure gas permeabilities. The present object is to model and simulate two-layer caulked gas separation membranes at the fundamental level to discover the mechanistic basis for the observed behaviour. To this end, a transport based model considering intrinsic material properties was developed to simulate gas separation for a system of CO 2 and N 2 diffusing across a caulking layer of polydimethyl siloxane (PDMS) and then a polyetherimide-polyethylene glycol interpenetrating network (PEI-PEG IPN) membrane. The model was able to account for flux declines in mixed gas systems greater than those predicted by conventional series resistance models, such as have been observed experimentally.

Synthesis and characterization of bis (4-maleimidophenyl) fluorene and its semi interpenetrating network membranes with polyether imide (Ultem® 1000)

Journal of Membrane Science, 2011

A semi-interpenetrating network (semi-IPN) of bis (4-maleimidophenyl) fluorene (cardo-BMI) and po... more A semi-interpenetrating network (semi-IPN) of bis (4-maleimidophenyl) fluorene (cardo-BMI) and polyether imide (PEI, Ultem ® 1000) was prepared. The structure of bis (4-maleimidophenyl) fluorene and the corresponding semi-IPNs was determined by nuclear magnetic resonance and Fourier transform infrared spectroscopy, respectively. The thermal properties of the cardo-BMI and semi-IPNs were evaluated by thermogravimetry and differential scanning calorimetry. The semi-IPNs exhibited thermal stability up to 480 • C. The morphology of the semi-IPNs was evaluated by scanning electron microscopy. Asymmetric membranes were prepared from the semi-IPN material by the wet phase inversion method. The pure gas permeation properties of the PEI and semi-IPN membranes were evaluated for oxygen (O 2), nitrogen (N 2), carbon dioxide (CO 2) and methane (CH 4) by the constant pressure and variable volume method at an absolute feed pressure of 0.69 MPa at 22 • C. The CO 2 /N 2 selectivity of 39.2 ± 3.0 with a CO 2 permeance of 18.3 ± 4.0 GPU of semi-IPN membrane was higher than the PEI membranes (selectivity 21.6 ± 4.1 and CO 2 permeance 0.5 ± 0.1 GPU). The highest CO 2 /CH 4 selectivity of the semi-IPN membrane was 49.3 ± 3.5 compared to 37 for a PEI dense film. Among the semi-IPN membranes, those with 5 wt% cardo-BMI exhibited better performance than the 1% and 10%.

Separation performance of asymmetric membranes based on PEGDa/PEI semi-interpenetrating polymer network in pure and binary gas mixtures of CO2, N2 and CH4

Journal of Membrane Science, 2010

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright

Design and economics of a hybrid membrane–temperature swing adsorption process for upgrading biogas

Journal of Membrane Science, 2012

Highlight s A hybrid membrane-temperature swing adsorption process for upgrading biogas to pipeli... more Highlight s A hybrid membrane-temperature swing adsorption process for upgrading biogas to pipeline quality methane is presented. Using an objective function a multi-stage process involving temperature swing adsorption and membranes was optimized. Techno-economic analysis showed that for processing 200 Nm 3 /h biogas stream, a payback time on the investment was 6.8 months.

Polysulfone membranes. V. Poly(phenyl sulfone) (Radel R)–poly(vinyl pyrrolidone) membranes

Journal of Applied Polymer Science, 1994

SYNOPSIS zyxwvutsrqpon Ultrafiltration membranes were prepared from mixtures of poly (phenyl sulf... more SYNOPSIS zyxwvutsrqpon Ultrafiltration membranes were prepared from mixtures of poly (phenyl sulfone) (Radel R5000) and poly(viny1 pyrrolidone) (PVP) dissolved in zyxwv 1-methyl-2-pyrrolidinone (NMP). The effects of the casting solution composition on membrane performance and morphology are presented. Radel R5000 membranes showed higher productivity for a given pore size when compared to other polysulfone membranes. The biphenyl group in Radel R5000 makes it more rigid in comparison to other polysulfones. This may result in more ordered packing, which resulted in the higher productivities and smaller pore sizes observed in the membranes. zyxwvuts