Imperial College London

Prof Jason P. Hallett

Faculty of EngineeringDepartment of Chemical Engineering

Professor of Sustainable Chemical Technology
 
 
 
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Contact

 

+44 (0)20 7594 5388j.hallett Website

 
 
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Location

 

228bBone BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

201 results found

Chambon CL, Verdía P, Fennell PS, Hallett Jet al., 2021, Process intensification of the ionosolv pretreatment: effects of biomass loading, particle size and 100-fold scale-up, Scientific Reports, Vol: 11, Pages: 1-15, ISSN: 2045-2322

Background: The ionoSolv process is one of the most promising technologies for biomass pretreatment in a biorefinery context. In order to evaluate the transition of the ionoSolv pretreatment of biomass from bench-scale experiments to biorefinery scale, there is a need to get better insight in process intensification. In this work, the effects of biomass loading, particle size, pulp washing protocols and 100-fold scale up for the pretreatment of the grassy biomass Miscanthus giganteus with the IL triethylammonium hydrogen sulfate, [TEA][HSO4], are presented. Results: At the bench scale, increasing biomass loading from 10 wt% to 50 wt% reduced glucose yields from 68% to 23% due to re-precipitation of lignin onto the pulp surface. Omitting the pulp air-drying step maintained saccharification yields at 66% at 50 wt% loading due to reduced fiber hornification. 100-fold scale-up (from 10 mL to 1 L) improved the efficacy of ionoSolv pretreatment and increasing loadings from 10 wt% to 20 wt% reduced lignin reprecipitation and led to higher glucose yields due to the improved heat and mass transfer caused by efficient slurry mixing in the reactor. Pretreatment of particle sizes of 1–3 mm was more effective than fine powders (0.18–0.85 mm) giving higher glucose yields due to reduced surface area available for lignin re-precipitation while reducing grinding energy needs.Conclusion: Stirred ionoSolv pretreatment showed great potential for industrialization and further process intensification after optimization of the pretreatment conditions (temperature, residence time, stirring speed), particle size and biomass loading. Pulp washing protocols need further improvement to reduce the incidence of lignin precipitation and the water requirements of lignin washing.

Journal article

Abouelela AR, Al Ghatta A, Verdia P, Koo MS, Lemus J, Hallett JPet al., 2021, Evaluating the Role of Water as a Cosolvent and an Antisolvent in [HSO4]-Based Protic Ionic Liquid Pretreatment, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 10524-10536, ISSN: 2168-0485

Journal article

Upcraft T, Tu W-C, Johnson R, Finnigan T, Van Hung N, Hallett J, Guo Met al., 2021, Protein from renewable resources: mycoprotein production from agricultural residues, GREEN CHEMISTRY, Vol: 23, Pages: 5150-5165, ISSN: 1463-9262

Journal article

Shmool TA, Martin LK, Bui-Le L, Moya-Ramirez I, Kotidis P, Matthews RP, Venter GA, Kontoravdi C, Polizzi KM, Hallett JPet al., 2021, An experimental approach probing the conformational transitions and energy landscape of antibodies: a glimmer of hope for reviving lost therapeutic candidates using ionic liquid, Chemical Science, Vol: 12, Pages: 9528-9545, ISSN: 2041-6520

Understanding protein folding in different environmental conditions is fundamentally important for predicting protein structures and developing innovative antibody formulations. While the thermodynamics and kinetics of folding and unfolding have been extensively studied by computational methods, experimental methods for determining antibody conformational transition pathways are lacking. Motivated to fill this gap, we prepared a series of unique formulations containing a high concentration of a chimeric immunoglobin G4 (IgG4) antibody with different excipients in the presence and absence of the ionic liquid (IL) choline dihydrogen phosphate. We determined the effects of different excipients and IL on protein thermal and structural stability by performing variable temperature circular dichroism and bio-layer interferometry analyses. To further rationalise the observations of conformational changes with temperature, we carried out molecular dynamics simulations on a single antibody binding fragment from IgG4 in the different formulations, at low and high temperatures. We developed a methodology to study the conformational transitions and associated thermodynamics of biomolecules, and we showed IL-induced conformational transitions. We showed that the increased propensity for conformational change was driven by preferential binding of the dihydrogen phosphate anion to the antibody fragment. Finally, we found that a formulation containing IL with sugar, amino acids and surfactant is a promising candidate for stabilising proteins against conformational destabilisation and aggregation. We hope that ultimately, we can help in the quest to understand the molecular basis of the stability of antibodies and protein misfolding phenomena and offer new candidate formulations with the potential to revive lost therapeutic candidates.

Journal article

Asim AM, Uroos M, Muhammad N, Hallett JPet al., 2021, Production of Food-Grade Glucose from Rice and Wheat Residues Using a Biocompatible Ionic Liquid, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 8080-8089, ISSN: 2168-0485

Journal article

Muazzam R, Asim AM, Uroos M, Muhammad N, Hallett JPet al., 2021, Evaluating the potential of a novel hardwood biomass using a superbase ionic liquid, RSC ADVANCES, Vol: 11, Pages: 19095-19105

Journal article

Hennequin L, Sas E, Frémont A, Jerbi A, Legault N, Lamontagne J, Fagoaga N, Sarrazin M, Hallett J, Fennell P, Barnabé S, Labrecque M, Brereton N, Pitre Fet al., 2021, Biorefinery potential of sustainable municipal wastewater treatment using fast-growing willow, Science of the Total Environment, ISSN: 0048-9697

Journal article

Hallett J, 2021, Rhododendron and Japanese Knotweed: invasive species as innovative crops for second generation biofuels, RSC Advances: an international journal to further the chemical sciences, Vol: 11, Pages: 18395-18403, ISSN: 2046-2069

We investigated the potential of two terrestrial biomass invasive species in the United-Kingdom as lignocellulosic biofuel feedstocks: Japanese Knotweed (Fallopia japonica) and Rhododendron (Rhododendron ponticum). We demonstrate that a pretreatment technique using a low-cost protic ionic liquid, the ionoSolv process, can be used for such types of plant species considered as waste, to allow their integration into a biorefinery. N,N,N-Dimethylbutylammonium hydrogen sulfate ([DMBA][HSO4]) was able to fractionate the biomass into a cellulose-rich pulp and a lignin stream at high temperatures (150–170 °C) and short reaction times (15–60 minutes). More than 70–80% of the subsequent cellulose was hydrolysed into fermentable sugars, which were fermented into the renewable energy vector bioethanol.

Journal article

Clarke CJ, Morgan PJ, Hallett JP, Licence Pet al., 2021, Linking the the Thermal and Electronic Properties of Functional Dicationic Salts with their Molecular Structures, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 6224-6234, ISSN: 2168-0485

Journal article

Yao JG, Tan S-Y, Metcalfe P, Fennell PS, Kelsall GH, Hallett JPet al., 2021, Demetallization of Sewage Sludge Using Low-Cost Ionic Liquids, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 55, Pages: 5291-5300, ISSN: 0013-936X

Journal article

Tan S-Y, Bedoya-Lora FE, Hallett JP, Kelsall GHet al., 2021, Evaluation of N,N,N-Dimethylbutylammonium methanesulfonate ionic liquid for electrochemical recovery of lead from lead-acid batteries, Electrochimica Acta, Vol: 376, Pages: 1-9, ISSN: 0013-4686

Physicochemical and electrochemical properties of N,N,N-dimethylbutylammonium methanesulfonate, [DMBA][MS], ionic liquid (IL) have been determined, and the potential application for electrochemical recovery of lead from lead-acid batteries is discussed. To optimise the transport properties of the IL, the dependences were measured of conductivity, density and viscosity with varying amounts of excess acid with water as a diluent in the electrolyte mixture. Molar conductivities obtained from the molar concentration and ionic conductivity measurements were used to quantify the ionicities of these IL mixtures. The solubility of PbII from PbCO3 was also shown to depend strongly on the IL composition. Preliminary results of the electrochemical kinetics of PbII reduction showed fast Pb deposition and potential-controlled electrodeposition morphologies of Pb, which may be advantageous for the design of up-scaled lead electrowinning processes.

Journal article

Bhatia R, Lad JB, Bosch M, Bryant DN, Leak D, Hallett JP, Franco TT, Gallagher JAet al., 2021, Production of oligosaccharides and biofuels from Miscanthus using combinatorial steam explosion and ionic liquid pretreatment, BIORESOURCE TECHNOLOGY, Vol: 323, ISSN: 0960-8524

Journal article

Clarke CJ, Matthews RP, Brogan APS, Hallett JPet al., 2021, Controlling surface chemistry and mechanical properties of metal ionogels through Lewis acidity and basicity, Journal of Materials Chemistry A, Vol: 9, Pages: 4679-4686, ISSN: 2050-7488

Ionogels are emerging as soft materials with remarkable physical properties that can be tuned to suit application requirements. The liquid component—ionic liquids—are effectively involatile, which provides new opportunities to explore gel surfaces with UHV based analytical techniques. Here, we exploit the highly solvating nature of ionic liquids to fabricate poly(ethylene glycol) based ionogels with high concentrations of zinc, and then investigate their surfaces to show that tunability extends beyond the bulk to the interface. A unique relationship between Lewis acidity and basicity and the surface concentration of metal was revealed. Chemical state analysis and molecular dynamics showed that Lewis acidic metals templated polymers to give new architectures reduced brittleness and increased flexibility, while Lewis basic metals improved polymer uniformity and strengthened gels. Therefore, bulk structure, surface composition, and metal speciation were all found to be intimately related and dependent upon the coordination strengths of ionic liquid anions. Importantly, the highly controllable surface and structural properties of metal ionogels allow fine-tuning across a broad design space, which presents new opportunities for gel based applications.

Journal article

Lemus J, Santiago R, Hospital-Benito D, Welton T, Hallett JP, Palomar Jet al., 2021, Process Analysis of Ionic Liquid-Based Blends as H2S Absorbents: Search for Thermodynamic/Kinetic Synergies, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 2080-2088, ISSN: 2168-0485

Journal article

Al Ghatta A, Zhou X, Casarano G, Wilton-Ely J, Hallett Jet al., 2021, Characterization and valorization of humins produced by HMF degradation in ionic liquids: a valuable carbonaceous material for antimony removal, ACS Sustainable Chemistry and Engineering, Vol: 9, Pages: 2212-2223, ISSN: 2168-0485

The processing of biomass in ionic liquids has demonstrated many benefits compared to organic solvents. This includes the maximization of 5-hydroxymethylfurfural (HMF) yield from sugars through the suppression of byproducts, such as formic acid and levulinic acid. Inefficiencies still exist due to the low stability of HMF at high temperature, leading to side reactions which ultimately result in the undesirable formation of humins. Valorization of this polymeric side product is thus needed to improve the economics of the biorefinery and could lead to humins being viewed as valuable materials for various applications. However, a much better understanding is needed of how humins form from HMF in the various ionic liquids proposed for the biorefinery. In this contribution, humin formation is probed by a range of analytical techniques, including FT-IR, SEM, solid-state 13C NMR, MS, GPC, and XPS analyses. This reveals that the structure and morphology of the humins formed does not resemble those reported in the literature and that the material displays a number of unique aspects. The hydrogen bonding proprieties of the ionic liquids employed exert a strong influence on the chemical functionality of the humins, and this is used to demonstrate their potential as functional materials. To demonstrate this, the humins produced in various ionic liquid environments are applied to metal extraction and compared with commercial activated carbon. This reveals that humins are superior for the extraction of antimony ions from wastewater, showing promise as an adsorbent additive for water purification.

Journal article

Cuellar-Franca RM, Garcia-Gutierrez P, Hallett JP, Mac Dowell Net al., 2021, A life cycle approach to solvent design: challenges and opportunities for ionic liquids - application to CO2 capture, REACTION CHEMISTRY & ENGINEERING, Vol: 6, Pages: 258-278, ISSN: 2058-9883

Journal article

Brandl P, Bui M, Hallett JP, Mac Dowell Net al., 2021, Beyond 90% capture: Possible, but at what cost?, International Journal of Greenhouse Gas Control, Vol: 105, Pages: 1-16, ISSN: 1750-5836

Carbon capture and storage (CCS) will have an essential role in meeting our climate change mitigation targets. CCS technologies are technically mature and will likely be deployed to decarbonise power, industry, heat, and removal of CO2 from the atmosphere. The assumption of a 90% CO2 capture rate has become ubiquitous in the literature, which has led to doubt around whether CO2 capture rates above 90% are even feasible. However, in the context of a 1.5 °C target, going beyond 90% capture will be vital, with residual emissions needing to be indirectly captured via carbon dioxide removal (CDR) technologies. Whilst there will be trade-offs between the cost of increased rates of CO2 capture, and the cost of offsets, understanding where this lies is key to minimising the dependence on CDR. This study quantifies the maximum limit of feasible CO2 capture rate for a range of power and industrial sources of CO2, beyond which abatement becomes uneconomical. In no case, was a capture rate of 90% found to be optimal, with capture rates of up to 98% possible at a relatively low marginal cost. Flue gas composition was found to be a key determinant of the cost of capture, with more dilute streams exhibiting a more pronounced minimum. Indirect capture by deploying complementary CDR is also assessed. The results show that current policy initiatives are unlikely to be sufficient to enable the economically viable deployment of CCS in all but a very few niche sectors of the economy.

Journal article

Al Ghatta A, Wilton-Ely J, Hallett J, 2021, From sugars to FDCA: A techno-economic assessment using a design concept based on solvent selection and carbon dioxide emissions, Green Chemistry, Vol: 23, Pages: 1716-1733, ISSN: 1463-9262

The synthesis of the molecule 2,5-furandicarboxylic acid (FDCA) from sugars is key to unlocking the potential for the replacement of the oil derivative PET (polyethylene terephthalate) by polyethylene furanoate (PEF). Although much research and investment has been dedicated to the synthesis of FDCA, there remains limited commercial activity in this area due to the challenges related to the stability and isolation of the FDCA precursor, 5-hydroxymethylfurfural (HMF). High yields of HMF can be obtained from fructose at high loadings in water–organic solvent mixtures (methyl isobutyl ketone, MIBK; γ-valerolactone, GVL), dimethyl sulfoxide (DMSO) or ionic liquids. Each of these approaches suffers from various drawbacks in terms of catalyst development, product separation and environmental impact. It is therefore necessary to understand which of these processes has the potential for scale-up, while ensuring low environmental impact and a competitive selling price. In this study, a process simulation (rather than a life cycle assessment) was performed to evaluate the associated emissions and selling price of FDCA based on its production using different solvents. It was determined that the cost and CO2 emissions associated with the isolation of HMF undermine the economic and environmental viability of the transformation of sugars to FDCA. In contrast, a two-step, one-pot reaction represents an ideal solution to reduce both cost and environmental impact, making FDCA competitive with terephthalic acid (the corresponding precursor for PET). The choice of solvent and the process were then evaluated and ranked based on safety, CO2 emissions, selling price and state of development though a scoring methodology. A system based on a water/GVL mixture is closer to commercial applicability but the process is limited by extensive formation of humins, which reduces the overall yield of the process, increasing the minimum selling price of FDCA. Using DMSO or ionic liquids mi

Journal article

Shmool TA, Martin LK, Clarke CJ, Bui-Le L, Polizzi KM, Hallett JPet al., 2021, Exploring conformational preferences of proteins: ionic liquid effects on the energy landscape of avidin, CHEMICAL SCIENCE, Vol: 12, Pages: 196-209, ISSN: 2041-6520

Journal article

Baaqel H, Hallett JP, Guillén-Gosálbez G, Chachuat Bet al., 2021, Uncertainty analysis in life-cycle assessment of early-stage processes and products: a case study in dialkyl-imidazolium ionic liquids, Computer Aided Chemical Engineering, Pages: 785-790

This paper presents a methodology for combining foreground and background uncertainty in the life-cycle assessment (LCA) of processes and products at a low technology-readiness level. We compare the LCA of two ionic liquids, 1-butyl-3-methyl-imidazoliumtetrafluoroborate [bmim][BF4] and 1-butyl-3-methyl-imidazolium hexafluorophosphate [bmim][PF6]. The nominal scenario predicts that [bmim][BF4] generates lower end-point environmental impacts than [bmim][PF6]. However, the uncertainty ranges around these nominal predictions overlap significantly, with [bmim][BF4] causing higher impacts than those of [bmim][PF6] in up to 30% of the uncertainty scenarios. On top of this, accounting for uncertainty in the foreground data more than doubles the estimated impact ranges in several damage categories. This case study, therefore, demonstrates the need for combining foreground and background data uncertainty for more reliable life-cycle assessments.

Book chapter

Nakasu PYS, Pin TC, Hallett JP, Rabelo SC, Costa ACet al., 2021, In-depth process parameter investigation into a protic ionic liquid pretreatment for 2G ethanol production, Renewable Energy, Vol: 172, Pages: 816-828, ISSN: 0960-1481

Protic ionic liquids (PILs) are promising pretreatment agents that can efficiently deconstruct lignocellulosic biomass for 2G ethanol production. PIL synthesis is less costly than that of aprotic imidazolium-based ILs thereby reducing the final ethanol price. However, a more comprehensive investigation is still necessary in order to better understand how PILs affect biomass during pretreatment. An investigation of process parameters was carried out for pretreatment of sugarcane bagasse using the PIL monoethanolammonium acetate, [MEA]OAc], focussing on main pretreatment parameters — time, temperature, solids loading, and water content. Optimal conditions were found to be 2 h, 150 °C, 15 wt% solids loading and 20 wt% water content. Lignin solubilization of almost 60 wt% was achieved with no carbohydrate losses, leading to 78.6% and 49% of cellulose and hemicellulose yields during saccharification. The addition of hemicellulases increased the hemicelluloses yield in saccharification to up to 66% with a high enzyme loading, 5.8 wt%. Ethanol, isopropanol, isoamyl alcohol and water were tested as anti-solvents; none of which led to higher sugar yields or modified recovered lignin structures, as confirmed by spectroscopic methods. Lignin analysis revealed the presence of S, G and H moieties, low degree of condensation, and a potential to produce aromatic compounds that could add value to the biorefinery.

Journal article

Malaret F, Hallett J, Campbell KS, 2020, Oxidative ionothermal synthesis for micro and macro Zn-based materials, MATERIALS ADVANCES, Vol: 1, Pages: 3597-3604

Journal article

Clarke CJ, Richardson ND, Firth AEJ, Hallett JP, Licence Pet al., 2020, Thermolysis of Organofluoroborate Ionic Liquids to NHC-Organofluoroborates, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 8, Pages: 16386-16390, ISSN: 2168-0485

Journal article

Bui-Le L, Brogan APS, Hallett JP, 2020, Solvent-free liquid avidin as a step toward cold chain elimination, BIOTECHNOLOGY AND BIOENGINEERING, Vol: 118, Pages: 592-600, ISSN: 0006-3592

Journal article

Skoronski E, Fernandes M, Malaret FJ, Hallett JPet al., 2020, Use of phosphonium ionic liquids for highly efficient extraction of phenolic compounds from water, Separation and Purification Technology, Vol: 248, Pages: 1-8, ISSN: 1383-5866

Ionic liquids (ILs) are undergoing development as extractants for phenolic compounds from wastewater due to their outstanding properties. Although many ILs have been considered, the use of phosphonium-based ILs has thus far been neglected, despite advantages in viscosity and low water solubility. This work details the application of phosphonium-based ILs for the liquid–liquid extraction of phenolic compounds from water. The selected target contaminants, phenol and 2,4-dichlorophenol, were extracted using two ILs composed of trihexyltetradecylphosphonium cations with decanoate or bis(2,4,4-trymetylpentyl)phosphinate anions. The effect of volume ratio, time of contact, pH, temperature and (inorganic) salt concentration on the extraction efficiency were examined. Additionally, the ILs used in this study were characterised in terms of water solubility and solvatochromic polarity. These ILs are less soluble in water than the others reported in the literature, and even at a volume ratio (water: ionic liquid) of 135, the IL can extract more than 99% and 89% of 2,4-dichlorophenol and phenol, respectively, in just 10 min, with the best extraction performance at lower temperatures and pH lower than the pKa of these phenolic compounds. Overall, these ILs demonstrate high potential for phenol extraction and can be considered as a powerful alternative for wastewater treatment.

Journal article

Abouelela AR, Tan S-Y, Kelsall GH, Hallett JPet al., 2020, Toward a Circular Economy: Decontamination and Valorization of Postconsumer Waste Wood Using the ionoSolv Process, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 8, Pages: 14441-14461, ISSN: 2168-0485

Journal article

Green S, Wheelhouse K, Payne A, Hallett J, Miller P, Bull Jet al., 2020, On the use of differential scanning calorimetry for thermal hazard assessment of new chemistry: Avoiding explosive mistakes, Angewandte Chemie International Edition, Vol: 59, Pages: 15798-15802, ISSN: 1433-7851

Differential scanning calorimetry (DSC) is increasingly used as evidence to support a favourable safety profile of novel chemistry, or to highlight the need for caution. DSC enables preliminary assessment of the thermal hazards of a potentially energetic compound. However, unlike other standard characterisation methods, which have well defined formats for reporting data, the current reporting of DSC results for thermal hazard assessment has shown concerning trends. Around half of all results in 2019 did not include experimental details required to replicate the procedure. Furthermore, analysis for thermal hazard assessment is often only conducted in unsealed crucibles, which could lead to misleading results and dangerously incorrect conclusions. We highlight the specific issues with DSC analysis of hazardous compounds currently in the organic chemistry literature and provide simple ‘best practice’ guidelines which will give chemists confidence in reported DSC results and the conclusions drawn from them.

Journal article

Green SP, Wheelhouse KM, Payne AD, Hallett JP, Miller PW, Bull JAet al., 2020, On the Use of Differential Scanning Calorimetry for Thermal Hazard Assessment of New Chemistry: Avoiding Explosive Mistakes, Angewandte Chemie, Vol: 132, Pages: 15930-15934, ISSN: 0044-8249

© 2020 Wiley-VCH GmbH Differential scanning calorimetry (DSC) is increasingly used as evidence to support a favourable safety profile of novel chemistry, or to highlight the need for caution. DSC enables preliminary assessment of the thermal hazards of a potentially energetic compound. However, unlike other standard characterisation methods, which have well defined formats for reporting data, the current reporting of DSC results for thermal hazard assessment has shown concerning trends. Around half of all results in 2019 did not include experimental details required to replicate the procedure. Furthermore, analysis for thermal hazard assessment is often only conducted in unsealed crucibles, which could lead to misleading results and dangerously incorrect conclusions. We highlight the specific issues with DSC analysis of hazardous compounds currently in the organic chemistry literature and provide simple “best practice” guidelines which will give chemists confidence in reported DSC results and the conclusions drawn from them.

Journal article

Tan S-Y, Hallett J, Geoff K, 2020, Electrodeposition of lead from methanesulfonic acid and methanesulfonate ionic liquid derivatives, Electrochimica Acta, Vol: 353, Pages: 1-11, ISSN: 0013-4686

The influence is reported of electrolyte composition on the electrochemistry of PbII and electrodeposition morphology of Pb in aqueous methanesulfonic acid (MSA) and two methanesulfonate-based ionic liquids: 1-butyl-3-methylimidazolium methanesulfonate and N,N-dimethylbutylammonium methanesulfonate. Cyclic voltammetry and chronoamperometry indicated that the reduction of PbII ions to Pb was a diffusion-controlled process proceeding via a two-electron transfer process at -0.67 V vs. Ag (1 M MSA) and involved 3-D progressive nucleation. Scanning electron microscopy showed a strong influence of deposition potential and electrolyte composition on the morphology of Pb deposits. Experimental data was used to model predictions of the specific electrical energy consumption for cathodic PbII electrodeposition coupled with either anodic oxygen evolution or PbO2 electrodeposition.

Journal article

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