Publications
413 results found
Schaepertoens M, Didaskalou C, Kim JF, et al., 2016, Solvent recycle with imperfect membranes: A semi-continuous workaround for diafiltration, Journal of Membrane Science, Vol: 514, Pages: 646-658, ISSN: 1873-3123
For separation of a two-component mixture, a three-stage organic solvent nanofiltration (OSN) process is presented which comprises of a two-stage membrane cascade for separation with a third membrane stage added for integrated solvent recovery, i.e. solvent recycling. The two-stage cascade allows for increased separation selectivity whilst the integrated solvent recovery stage mitigates the otherwise large solvent consumption of the purification. This work explores the effect of washing the solvent recovery unit at intervals in order to attain high product purities with imperfect solvent recovery membranes possessing less than 100% rejection of the impurity. This operation attains a purity of 98.7% through semi-continuous operation with two washes of the solvent recovery stage, even when imperfect membranes are used in a closed-loop set-up. This contrasts favourably with the 83.0% maximum purity achievable in a similar set-up with a single continuous run. The process achieves slightly lower (−0.7%) yield of around 98.2% compared to a continuously operated process without solvent recovery but consumes approx. 85% less solvent (theoretical analysis suggests up to 96% reduction is possible). 9 different membranes, both commercial (GMT, Novamem, SolSep) and in-house fabricated, are screened and tested on a separation challenge associated with the synthesis of macrocycles – amongst the membrane materials are polyimide (PI), polybenzimidazole (PBI) and, polyetheretherketone (PEEK).
Da Silva Burgal J, Peeva L, Livingston AG, 2016, Towards improved membrane production: using low-toxicity solvents for the preparation of PEEK nanofiltration membranes, Green Chemistry, Vol: 18, ISSN: 1744-1560
In this work it is shown that PEEK membranes are “green” from the production point of view when compared with commercial polyimide (PI) based organic solvent nanofiltration (OSN) membranes. Green metrics (E-factor and solvent intensity) and waste cost were used in order to assess the environmental burden of PEEK membranes: the solvent intensity of PEEK membranes is 8.3 vs. 35–224 for PI based membranes, and the waste cost for PEEK membranes is 46 £ kg−1 of polymer vs. 1019 £ kg−1 of polymer (bench scale) and 189 £ kg−1 of polymer (industrial scale) for PI based membranes. Scaling-up of PEEK membranes to spiral-wound modules was successfully achieved with permeances between 0.26 L h−1 m−2 bar−1 and 0.47 L h−1 m−2 bar−1 for THF, and molecular weight cut-offs (MWCO) of ∼300 g mol−1. As a final assessment, the solvent intensity and environmental burden associated with permeating a THF flow of 100 L h−1 using PEEK membranes was also assessed. The results showed a waste cost of 1.4 £ m−2 of membrane, significantly lower than PI based membranes.
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.
Campbell J, Burgal JDS, Szekely G, et al., 2016, Hybrid polymer/MOF membranes for Organic Solvent Nanofiltration (OSN): chemical modification and the quest for perfection, Journal of Membrane Science, Vol: 503, Pages: 166-176, ISSN: 1873-3123
One of the main challenges in the field of Organic Solvent Nanofiltration (OSN) is to improve the selectivity of membranes, allowing the separation of closely related solutes. This objective might be achieved by constructing membranes with uniform porous structures. Hybrid Polymer/Metal Organic Framework (MOF) membranes were prepared by in-situ growth (ISG) of HKUST-1 within the pores of polyimide membranes. To improve the performances of ISG membranes, chemical modification was performed. Aryl carboxylic acid moieties were introduced to polyimide P84 ultrafiltration membranes allowing coordination of the HKUST-1 directly on to the polymer. Chemically modified ISG membranes outperformed non-modified ISG membranes in both solute retentions and permeance. Retentions of polystyrene solute in acetone were used to calculate theoretical pore size distributions for each of the membranes tested. It was found that the chemically modified ISG membrane had he narrowest calculated pore size distribution.
Karan S, Jiang Z, Livingston AG, 2016, Sub-10 nm polyamide nanofilms with ultrafast solvent transport for molecular separation
Marchetti P, Shi B, Peshev D, et al., 2016, Membrane performance characterization and process prediction in OSN: Challenges, achievements and perspective, Pages: 104-105
Jimenez-Solomon MF, Song Q, Jelfs KE, et al., 2016, Polymer nanofilms with enhanced microporosity by interfacial polymerisation for molecular separations
Adi VSK, Cook M, Peeva LG, et al., 2016, Optimization of OSN Membrane Cascades for Separating Organic Mixtures, Editors: Kravanja, Bogataj, Publisher: ELSEVIER SCIENCE BV, Pages: 379-384
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- Citations: 10
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
Yeo BJL, Goh S, Zhang J, et al., 2015, Novel MBRs for the removal of organic priority pollutants from industrial wastewaters: a review, JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY, Vol: 90, Pages: 1949-1967, ISSN: 0268-2575
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- Citations: 26
Mazlan NM, Peshev D, Livingston AG, 2015, Energy consumption for desalination - a comparison of forward osmosis with reverse osmosis, and the potential for perfect membranes, Desalination, Vol: 377, Pages: 138-151, ISSN: 0011-9164
Reverse osmosis (RO) is now the most ubiquitous technology for desalination, with numerous seawater ROplants being built in water-stressed countries to complement existing water resources. Despite the developmentof highly permeable RO membranes, energy consumption remains a major contributor to total cost. Forward osmosis(FO) is receiving much attention as a potentially lower energy alternative to RO. However, the draw solution(DS) recovery step in FO requires significant energy consumption. The present study is a modellingapproach, simulating FO and RO desalination under various process conditions and process flow schemesusing the Aspen Plus environment. Results suggest that there is practically no difference in specific energy consumption(SEC) between standalone RO, and FO with nanofiltration (NF) DS recovery; this can be generalised forany pressure-driven membrane process used for the DS recovery stage in a hybrid FO process. Furthermore, evenif any or all of the membranes considered, FO, RO or NF, were perfect (i.e. had infinite permeance and 100%rejection), it would not change the SEC significantly. Hence, any advantage possessed by the FO with NF recoveryprocess derives from the lower fouling propensity of FO, which may reduce or eliminate the need for pretreatmentand chemical cleaning
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.
Karan S, Jiang Z, Livingston AG, 2015, Sub-10 nm polyamide nanofilms with ultrafast solvent transport for molecular separation, Science, Vol: 348, Pages: 1347-1351, ISSN: 0036-8075
Membranes with unprecedented solvent permeance and high retention of dissolved solutes are needed to reduce the energy consumed by separations in organic liquids. We used controlled interfacial polymerization to form free-standing polyamide nanofilms less than 10 nanometers in thickness, and incorporated them as separating layers in composite membranes. Manipulation of nanofilm morphology by control of interfacial reaction conditions enabled the creation of smooth or crumpled textures; the nanofilms were sufficiently rigid that the crumpled textures could withstand pressurized filtration, resulting in increased permeable area. Composite membranes comprising crumpled nanofilms on alumina supports provided high retention of solutes, with acetonitrile permeances up to 112 liters per square meter per hour per bar. This is more than two orders of magnitude higher than permeances of commercially available membranes with equivalent solute retention.
Gaffney PRJ, Kim JF, Valtcheva IB, et al., 2015, Liquid-phase synthesis of 2′-methyl-RNA on a homostar support through organic-solvent nanofiltration, Chemistry-A European Journal, Vol: 21, Pages: 9535-9543, ISSN: 1521-3765
Due to the discovery of RNAi, oligonucleotides (oligos) have re-emerged as a major pharmaceutical target that may soon be required in ton quantities. However, it is questionable whether solid-phase oligo synthesis (SPOS) methods can provide a scalable synthesis. Liquid-phase oligo synthesis (LPOS) is intrinsically scalable and amenable to standard industrial batch synthesis techniques. However, most reported LPOS strategies rely upon at least one precipitation per chain extension cycle to separate the growing oligonucleotide from reaction debris. Precipitation can be difficult to develop and control on an industrial scale and, because many precipitations would be required to prepare a therapeutic oligonucleotide, we contend that this approach is not viable for large-scale industrial preparation. We are developing an LPOS synthetic strategy for 2′-methyl RNA phosphorothioate that is more amenable to standard batch production techniques, using organic solvent nanofiltration (OSN) as the critical scalable separation technology. We report the first LPOS-OSN preparation of a 2′-Me RNA phosphorothioate 9-mer, using commercial phosphoramidite monomers, and monitoring all reactions by HPLC, 31P NMR spectroscopy and MS.
Burgal JDS, Peeva LG, Kumbharkar S, et al., 2015, Organic solvent resistant poly(ether-ether-ketone) nanofiltration membranes, JOURNAL OF MEMBRANE SCIENCE, Vol: 479, Pages: 105-116, ISSN: 0376-7388
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- Citations: 103
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
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- Citations: 65
Marchetti P, Mechelhoff M, Livingston AG, 2015, Tunable-porosity membranes for water treatment by discrete nanoparticle assembly, Pages: 196-197
Livingston A, 2015, "Crumpled" filter has the potential to slash energy consumption in industry, Membrane Technology, Vol: 2015, ISSN: 0958-2118
Solomon MFJ, Song Q, Munoz-Ibanez M, et al., 2015, TFC membranes with intrinsic microporosity by interfacial polymerization for organic solvent nanofiltration, Pages: 679-680
Bismarck A, Li K, Livingston A, 2015, Editorial "Polymers for membrane applications", REACTIVE & FUNCTIONAL POLYMERS, Vol: 86, Pages: 87-87, ISSN: 1381-5148
Szekely G, Valtcheva IB, Kim JF, et al., 2015, Molecularly imprinted organic solvent nanofiltration membranes - Revealing molecular recognition and solute rejection behaviour, REACTIVE & FUNCTIONAL POLYMERS, Vol: 86, Pages: 215-224, ISSN: 1381-5148
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- Citations: 59
Yau HC, Bayazit MK, Gaffney PRJ, et al., 2015, Synthesis and characterization of branched fullerene-terminated poly(ethylene glycol)s, POLYMER CHEMISTRY, Vol: 6, Pages: 1056-1065, ISSN: 1759-9954
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- Citations: 3
Campbell J, Davies RP, Braddock DC, et al., 2015, Improving the permeance of hybrid polymer/metal-organic framework (MOF) membranes for organic solvent nanofiltration (OSN) - development of MOF thin films via interfacial synthesis, JOURNAL OF MATERIALS CHEMISTRY A, Vol: 3, Pages: 9668-9674, ISSN: 2050-7488
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- Citations: 120
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
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- Citations: 1081
Kim JF, Szekely G, Schaepertoens M, et al., 2014, In Situ Solvent Recovery by Organic Solvent Nanofiltration, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 2, Pages: 2371-2379, ISSN: 2168-0485
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- Citations: 60
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
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- Citations: 245
Peeva L, Burgal JDS, Valtcheva I, et al., 2014, Continuous purification of active pharmaceutical ingredients using multistage organic solvent nanofiltration membrane cascade, CHEMICAL ENGINEERING SCIENCE, Vol: 116, Pages: 183-194, ISSN: 0009-2509
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- Citations: 57
Siddique H, Bhole Y, Peeva LG, et al., 2014, Pore preserving crosslinkers for polyimide OSN membranes, JOURNAL OF MEMBRANE SCIENCE, Vol: 465, Pages: 138-150, ISSN: 0376-7388
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- Citations: 41
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