28 results found
Dong R, Liu R, Gaffney P, et al., 2019, Sequence-defined multifunctional polyethers via liquid-phase synthesis with molecular sieving, Nature Chemistry, Vol: 11, Pages: 136-145, ISSN: 1755-4330
Synthetic chemists have devoted tremendous effort towards the production of precision synthetic polymers with defined sequences and specific functions. However, the creation of a general technology that enables precise control over monomer sequence, with efficient isolation of the target polymers, is highly challenging. Here, we report a robust strategy for the production of sequence-defined synthetic polymers through a combination of liquid-phase synthesis and selective molecular sieving. The polymer is assembled in solution with real-time monitoring to ensure couplings proceed to completion, on a three-armed star-shaped macromolecule to maximize efficiency during the molecular sieving process. This approach is applied to the construction of sequence-defined polyethers, with side-arms at precisely defined locations that can undergo site-selective modification after polymerization. Using this versatile strategy, we have introduced structural and functional diversity into sequence-defined polyethers, unlocking their potential for real-life applications in nanotechnology, healthcare and information storage.
Dong R, Liu R, Gaffney PRJ, et al., 2019, Author Correction: Sequence-defined multifunctional polyethers via liquid-phase synthesis with molecular sieving, Nature Chemistry, Vol: 11, Pages: 184-184, ISSN: 1755-4330
Correction to: Nature Chemistry https://doi.org/10.1038/s41557-018-0169-6, published online 3 December 2018.
Peeva LG, Marchetti P, Livingston AG, 2018, Nanofiltration operations in nonaqueous systems, Comprehensive Membrane Science and Engineering: Second Edition, Pages: 36-78, ISBN: 9780444637963
Nanofiltration is a pressure-driven membrane process used to remove solutes with molecular weight in the range of 200-2000 g mol-1, typically from aqueous streams. A relatively recent innovation is the extension of nanofiltration (NF) processes to organic solvents (OSs)-an emerging technology referred to as organic solvent nanofiltration (OSN). Separation of molecules present in OSs by NF has great potential in industries ranging from refining to fine chemical and pharmaceutical synthesis, and OSN is currently an area of intensive investigation. This article summarizes the most recent developments in the field of OSN.
Marchetti P, Peeva L, Livingston A, 2017, The Selectivity Challenge in Organic Solvent Nanofiltration: Membrane and Process Solutions, ANNUAL REVIEW OF CHEMICAL AND BIOMOLECULAR ENGINEERING, VOL 8, Vol: 8, Pages: 473-497, ISSN: 1947-5438
Shi B, Marchetti P, Peshev D, et al., 2016, Will ultra-high permeance membranes lead to ultra-efficient processes? Challenges for molecular separations in liquid systems, JOURNAL OF MEMBRANE SCIENCE, Vol: 525, Pages: 35-47, ISSN: 0376-7388
Mazlan NM, Marchetti P, Maples HA, et al., 2016, Organic fouling behaviour of structurally and chemically different forward osmosis membranes – A study of cellulose triacetate and thin film composite membranes, Journal of Membrane Science, Vol: 520, Pages: 247-261, ISSN: 0376-7388
The HTI cellulose triacetate (CTA) and novel thin film composite (TFC) membranes are used to study the multifaceted interactions involved in the fouling and cleaning of forward osmosis (FO) membranes, using calcium alginate as a model foulant. Results show that fouling on the TFC membrane was more significant compared to CTA, arising from a variety of factors associated with surface chemistry, membrane morphology and structural properties. Interestingly, it was observed that in FO mode, membrane surface properties dominated over fouling layer properties in determining fouling behaviour, with some surface properties (e.g. surface roughness) having a greater effect on fouling than others (e.g. surface hydrophilicity). In pressure retarded osmosis (PRO) mode, structural properties of the support played a more dominant role whereby fouling mechanism was specific to the foulant size and aggregation as well as the support pore size relative to the foulant. Whilst pore clogging was observed in the TFC membrane due to its highly asymmetric and porous support structure, fouling occurred as a surface phenomenon on the CTA membrane support layer. Besides pore clogging, the severe fouling observed on the TFC membrane in PRO mode was due to a high specific mass of foulant adsorbed in its porous support. It was observed that a trade-off between enhanced membrane performance and fouling mitigation is apparent in these membranes, with both membranes providing improvement in one aspect at the expense of the other. Hence, significant developments in their surface and structural properties are needed to achieve high anti-fouling properties without compromising flux performance. Measured fouling densities on the studied surfaces suggest that there is not a strong correlation between foulant-membrane interaction and fouling density. Cleaning results suggest that physical cleaning was more efficient on the CTA membrane compared to the TFC membrane. Further, they implied that despite diff
Shi B, Peshev D, Marchetti P, et al., 2016, Multi-scale modelling of OSN batch concentration with spiral-wound membrane modules using OSN Designer, Chemical Engineering Research & Design, Vol: 109, Pages: 385-396, ISSN: 1744-3563
Three commercial spiral-wound membrane modules of different sizes, from 1.8″ × 12″ to 4.0″ × 40″, are used to concentrate a solution of sucrose octaacetate in ethyl acetate under different operating conditions. A mathematical model to describe the batch concentration process is developed, based on a combination of the classical solution diffusion membrane transport model and the film theory, to account for the mass transfer effects. The model was implemented using the “OSN Designer” software tool. The membrane transport model parameters as well as all parameters in the pressure drop and mass transfer correlations for the spiral-wound modules were obtained from regression on a limited number of experimental data at steady state conditions. Excellent agreement was found between the experimental and multi-scale modelling performance data under various operating conditions. The results illustrate that the performance of a large scale batch concentration process with spiral-wound membrane modules can be predicted based on laboratory crossflow flat sheet test data when the fluid dynamics and mass transfer characteristics in the module, and the necessary channel geometry are known. In addition, the effects of concentration polarisation, pressure drop through feed and permeate channels, and thermodynamic non-ideality of the solution at large scale batch concentration are also investigated.
Marchetti P, Shi B, Peshev D, et al., 2016, Membrane performance characterization and process prediction in OSN: Challenges, achievements and perspective, Pages: 104-105
Marchetti P, Mechelhoff M, Livingston A, 2015, Tunable-porosity membranes from discrete nanoparticles, Scientific Reports, Vol: 5, ISSN: 2045-2322
Thin film composite membranes were prepared through a facile single-step wire-wound rod coating procedure in which internally crosslinked poly(styrene-co-butadiene) polymer nanoparticles self-assembled to form a thin film on a hydrophilic ultrafiltration support. This nanoparticle film provided a defect-free separation layer 130–150 nm thick, which was highly permeable and able to withstand aggressive pH conditions beyond the range of available commercial membranes. The nanoparticles were found to coalesce to form a rubbery film when heated above their glass transition temperature (Tg). The retention properties of the novel membrane were strongly affected by charge repulsion, due to the negative charge of the hydroxyl functionalized nanoparticles. Porosity was tuned by annealing the membranes at different temperatures, below and above the nanoparticle Tg. This enabled fabrication of membranes with varying performance. Nanofiltration properties were achieved with a molecular weight cut-off below 500 g mol⁻¹ and a low fouling tendency. Interestingly, after annealing above Tg, memory of the interstitial spaces between the nanoparticles persisted. This memory led to significant water permeance, in marked contrast to the almost impermeable films cast from a solution of the same polymer.
Shi B, Marchetti P, Peshev D, et al., 2015, Performance of spiral-wound membrane modules in organic solvent nanofiltration – Fluid dynamics and mass transfer characteristics, Journal of Membrane Science, Vol: 494, Pages: 8-24, ISSN: 1873-3123
Valtcheva IB, Marchetti P, Livingston AG, 2015, Crosslinked polybenzimidazole membranes for organic solvent nanofiltration (OSN): Analysis of crosslinking reaction mechanism and effects of reaction parameters, Journal of Membrane Science, Vol: 493, Pages: 568-579, ISSN: 0376-7388
Recently, polybenzimidazole (PBI) membranes crosslinked with dibromoxylene (DBX) were shown to retain their molecular separation performance in the harsh conditions characteristic of organic solvent nanofiltration (OSN). This work is focused on better understanding of the crosslinking reaction between PBI and DBX, and finding the parameters important for achieving higher degrees of crosslinking. A statistical approach based on Design of Experiments was used to identify the most significant parameters and interactions affecting the crosslinking reaction. High gain in weight and high bromine content after the reaction are expected to be indirectly related to membranes with high crosslinking degrees. Hence, these two responses were measured as a function of reaction temperature, reaction time, excess of DBX, concentration of DBX and reaction solvent (acetonitrile and toluene). All parameters were found to have a positive effect on both responses, and the reaction was found to be faster in acetonitrile than in toluene. All obtained results were statistically evaluated using Analysis of Variance, and a physical interpretation of the statistical models was attempted.Keywords Polybenzimidazole (PBI); Crosslinking reaction; Alkylation; Design of Experiments (DoE); Organic solvent nanofiltration (OSN)
Da Silva Burgal J, Peeva L, Marchetti P, et al., 2015, Controlling molecular weight cut-off of PEEK nanofiltration membranes using a drying method, Journal of Membrane Science, Vol: 493, Pages: 524-538, ISSN: 0376-7388
In this research paper we report two ways of controlling the molecular weight cut-off (MWCO) of PEEK membranes prepared via phase inversion and subsequent drying. The two methods explored were the change of polymer concentration in the dope solution – 8 wt. %, 10 wt. % and 12 wt. %-and the variation of solvent filling the pores prior to drying – e.g. water, methanol, acetone, tetrahydrofuran and n-heptane. The results show that it is possible to vary the MWCO from 295 g.mol−1 to 1400 g.mol−1 by varying these parameters. A statistical analysis based on a genetic algorithm showed that the Hansen solubility parameter, polarity and their interactions with molar volume were likely to be the most important parameters influencing the performance of PEEK membranes when drying from different solvents. In addition, the drying temperature also proved to have an effect on the membrane performance-the higher the temperature the higher the rejection and the lower the permeance.
Marchetti P, Livingston AG, 2015, Predictive membrane transport models for Organic Solvent Nanofiltration: How complex do we need to be?, JOURNAL OF MEMBRANE SCIENCE, Vol: 476, Pages: 530-553, ISSN: 0376-7388
Marchetti P, Mechelhoff M, Livingston AG, 2015, Tunable-porosity membranes for water treatment by discrete nanoparticle assembly, Pages: 196-197
Marchetti P, Solomon MFJ, Szekely G, et al., 2014, Molecular Separation with Organic Solvent Nanofiltration: A Critical Review, CHEMICAL REVIEWS, Vol: 114, Pages: 10735-10806, ISSN: 0009-2665
Szekely G, Jimenez-Solomon MF, Marchetti P, et al., 2014, Sustainability assessment of organic solvent nanofiltration: from fabrication to application, GREEN CHEMISTRY, Vol: 16, Pages: 4440-4473, ISSN: 1463-9262
Marchetti P, Butté A, Livingston A G, 2014, Reactive Peptide Nanofiltration, Sustainable Nanotechnology and the Environment: Advances and Achievements, Editors: Shamim, Sharma, Publisher: OUP USA, ISBN: 9780841227842
Combines green chemistry, sustainability, and nanotechnology, in order to create approaches for green nanotechnology.
Marchetti P, Butte A, Livingston AG, 2013, NF in organic solvent/water mixtures: Role of preferential solvation, JOURNAL OF MEMBRANE SCIENCE, Vol: 444, Pages: 101-115, ISSN: 0376-7388
Szekely G, Marchetti P, Jimenez-Solomon M F, et al., 2013, Organic Solvent Nanofiltration, Encyclopedia of Membrane Science and Technology, Editors: Hoek, Publisher: Wiley, ISBN: 9780470919446
This 3-volume encyclopedia covers all aspects of synthetic membranes at the fundamental as well as practical levels.
Marchetti P, Butte A, Livingston AG, 2013, Quality by Design for peptide nanofiltration: Fundamental understanding and process selection, CHEMICAL ENGINEERING SCIENCE, Vol: 101, Pages: 200-212, ISSN: 0009-2509
Marchetti P, Butté A, Livingston AG, 2013, Solute-solvent-membrane interactions in organic solvent nanofiltration, Pages: 518-520
Marchetti P, Butte A, Livingston AG, 2013, Reactive Peptide Nanofiltration, SUSTAINABLE NANOTECHNOLOGY AND THE ENVIRONMENT: ADVANCES AND ACHIEVEMENTS, Vol: 1124, Pages: 121-150, ISSN: 0097-6156
Marchetti P, Butte A, Livingston AG, 2013, Peptide nanofiltration by quality by design, Pages: 709-711
Marchetti P, 2013, Organic Solvent Nanofiltration in the Peptide Industry
Marchetti P, Butte A, Livingston AG, 2012, An improved phenomenological model for prediction of solvent permeation through ceramic NF and UF membranes, JOURNAL OF MEMBRANE SCIENCE, Vol: 415, Pages: 444-458, ISSN: 0376-7388
Marchetti P, Butte A, Livingston AG, 2012, Improved model for solvent permeation through NF and UF membranes, EUROMEMBRANE CONFERENCE 2012, Vol: 44, Pages: 394-397, ISSN: 1877-7058
Perale G, Rossi F, Santoro M, et al., 2011, Drug Release from Hydrogel: A New Understanding of Transport Phenomena, Journal of Biomedical Nanotechnology, Vol: 7, Pages: 476-481, ISSN: 1550-7033
Santoro M, Marchetti P, Rossi F, et al., 2011, Smart Approach To Evaluate Drug Diffusivity in Injectable Agar−Carbomer Hydrogels for Drug Delivery, The Journal of Physical Chemistry B, Vol: 115, Pages: 2503-2510, ISSN: 1520-6106
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