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Deployment of carbon capture and storage (CCS) technologies is the one of the key strategies to decarbonise the energy system in order to abate the consequences of climate change. Nevertheless, carbon capture is facing some challenges that are deterring its implementation. The capital costs are considered to be very high, and the energy required for solvent regeneration imposes an efficiency penalty on the power plant with which it is integrated. Therefore, it is imperative to seek for opportunities to reduce the overall cost of the CCS. This work focuses on the design strategies for new solvents for the capture of CO 2 from power plants. We have developed a process performance indexed screening tool to assess the suitability of new solvents based on economic, energetic and environmental performance indices. The physicochemical properties of the solvents that lead to reduction of the capture cost have been determined. [ABSTRACT FROM AUTHOR]

• We identify a hypothetical ideal solvent to demonstrate the limits of solvent development. • The CO 2 capture costs of the ideal limiting solvent was estimated to be $26/t CO 2. • Further development of aqueous systems unlikely to yield required cost reductions. • To deliver affordable carbon capture, a new technology paradigm is required. • Synergies between solvent and process design may be exploited to decrease costs. Absorption-based separation processes date back over 120 years, and are recognized as being integral to the delivery of deep decarbonisation. Thousands of new solvents have been proposed but have not yet delivered the level of cost reduction which has been widely anticipated. For much of the past 50 years, the scientific community has focused on developing novel aqueous blends of amines. Whilst they outperform benchmark technologies, they ultimately fail to address the fundamental performance limiting issue; the solvents overwhelmingly consist of water. In this contribution, we present a thought-experiment that uses a hypothetical solvent to identify the limit of available cost reductions to 65% over current performance benchmarks, reaching a cost limit of $26/ton CO 2 for gas-power. [ABSTRACT FROM AUTHOR]

Abstract: Homogeneous catalysts offer many advantages over heterogeneous catalysts, such as higher activities and selectivities. However, recovery of homogeneous catalysts is often complicated by difficulties in separating these complexes from the reaction products. The use of gaseous carbon dioxide (CO2) as miscibility switch for organic and fluorous phases has been proposed to overcome this limitation. By using CO2 as a cosolvent, polar organic reactants can be homogenized with catalysts immobilized in a fluorous phase without using elevated temperatures. The phase behavior underlying this concept is investigated. High-pressure phase equilibria for the systems containing carbon dioxide, an organic (methanol, toluene, or acetone), and perfluoro-n-hexane were measured using a variable-volume view cell, by a method capable of rapid and facile measurement of compositions and density in both phases with no sampling or calibration. [Copyright &y& Elsevier]

• Origins of 90% capture assumption explained. • Cost of near 100% capture calculated. • CO 2 concentration drives costs of capture. 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 CO 2 from the atmosphere. The assumption of a 90% CO 2 capture rate has become ubiquitous in the literature, which has led to doubt around whether CO 2 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 CO 2 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 CO 2 capture rate for a range of power and industrial sources of CO 2 , 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. [ABSTRACT FROM AUTHOR]

The effects are 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 an overall 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 PbO 2 electrodeposition. Image 1 [ABSTRACT FROM AUTHOR]

Thermoresponsive polymers have attracted much scientific attention due to their capacity for temperature-driven hydrogel formation. For biomedical applications, such as drug delivery, this transition should be tuned below body temperature to facilitate controlled and targeted drug release. We have recently developed a thermoresponsive polymer that forms gel at low concentrations (2 w/w%) in aqueous media and offers a cost-effective alternative to thermoresponsive systems currently being applied in clinics. This polymer is an ABC triblock terpolymer, where A, B, and C correspond to oligo(ethylene glycol) methyl ether methacrylate with average M n 300 g mol−1 (OEGMA300), n -butyl methacrylate (BuMA), and di(ethylene glycol) methyl ether methacrylate (DEGMA). To investigate the self-assembly and the gelation mechanism in diluted solutions, we used small-angle neutron scattering (SANS) on 1 w/w% (below the gelation concentration) and 5 w/w% solutions (above the gelation concentration). As a comparison, we also investigated the solutions of the most studied thermoresponsive polymer, namely, Pluronic F127, an ABA triblock bipolymer made of ethylene glycol (A) and propylene glycol (B) blocks. SANS revealed that the in-house synthesised polymer forms elliptical cylinders, whose length increases significantly with temperature. In contrast, Pluronic F127 solutions form core-shell spherical micelles, which slightly elongate with temperature. Transmission electron microscopy images support the SANS findings, with tubular/worm structures being present. Variable-temperature circular dichroism (CD) and proton nuclear magnetic resonance (1H NMR) spectroscopy experiments reveal insights on the tacticity, structural changes, and molecular origin of the self-assembly. [Display omitted] • Worm like micelles versus spherical micelles self-assembly and gelation. • Differences between the thermoresponsive behaviour of an ABC and an ABA triblock copolymer. • Tubular/worm like micelles can induce gelation at lower concentrations than spherical micelles. [ABSTRACT FROM AUTHOR]

Abstract: The acetylacetonate complexes of oxovanadium(IV): VO(X-acac)2 (X=Cl, CH3 and CH3CH2) were structurally characterized in several alkylimidazolium ionic liquids by visible absorption and EPR spectroscopies. VO(Me-acac)2 and VO(Et-acac)2 showed solvatochromism in the selected ionic liquids (a λ 1 shift of ca. 120nm was observed) and most complexes showed two species in the anisotropic EPR spectra in several ionic liquids. It was shown that the ionic liquids anions have coordinating ability and the basicity order found was: NTf2 − 95% conversion to sulfone. The ionic liquid that showed the best performance with all substrates was bmimNTf2. In bmimOTf and bmimBF4 the activity of all catalysts in the ECODS system was low to moderate, which is probably due to the higher coordinating ability of these anions. [Copyright &y& Elsevier]

• PbII solubilities of 0.9 M were measured in [DMBA][MS] • Molar conductivities exceeded those of a Walden plot's KCl reference line • Cyclic voltammograms implied fast Pb deposition • Morphologies of Pb electrodeposits were potential-dependent 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 PbCO 3 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. [ABSTRACT FROM AUTHOR]

As the costs of solar PV continuously decrease and pollution legislation imposes less burning of agricultural residues, decentralized renewable energy is increasingly affordable for providing electricity to one billion people lacking access to a power grid. This paper presents a techno-economic feasibility case study of biomass gasification in off-grid and grid-connected mini-grids for community-scale energy application in rural Uttar Pradesh, India. Energy demand data was collected through surveys in a village with irrigation and agro-processing loads and off-grid households and used to construct a seasonal load profile based on statistical methods. This was used to simulate single-source and hybrid mini-grids based on solar PV, biomass gasification and diesel generation using HOMER Pro. Hybrid PV-biomass or PV-diesel systems were found to offer the highest reliability for off-grid power at the lowest cost. Single-source PV was cheaper than biomass gasification, though the cost of electricity is highly sensitive to biomass supply and gasifier maintenance. Both renewable options were around half the cost of diesel generation. The findings held across grid-connected systems with weak, moderate and strong reliability of grid supply. This suggests that biomass gasification-based mini-grids are not cost-competitive with PV unless the two generation sources are combined in a hybrid system, though they require operational testing prior to implementation. Image 1 • Hybrid PV–biomass or PV–diesel systems offer higher reliability at lower cost. • PV is cheaper than biomass gasification mini-grids for productive energy provision. • Grid-connected PV offers lowest LCOE over 20 years for strong and weak grid supply. • LCOE of biomass systems is highly sensitive to biomass requirement and maintenance. • PV–biomass systems appear resilient to operating parameters but lack field testing. [ABSTRACT FROM AUTHOR]

The potential of perennial bioenergy Miscanthus feedstock grown on heavy metal contaminated land was evaluated for the production of clean renewable energy, chemicals, and recovered metals. Trace element analysis showed significant levels of metal contaminants from the harvested Miscanthus : 6.47 g of Pb per kg of biomass, 1.91 g kg−1 Fe, 0.35 g kg−1 Zn, 26.59 mg kg−1 of Cu; along with other metals including Cr, Ni, As and Cd. The protic ionic liquid, 1-methylimidazolium chloride [H 1 Cim]Cl, extracted 99.3% of Pb from the biomass along with 96–98% of Cu, Zn and Cd, and produced a clean cellulose pulp, which was successfully saccharified into glucose with an 81.5% yield. The behaviour of PbII in aqueous solutions of [H 1 Cim]Cl showed that this ionic liquid medium supported the electrochemical reduction of PbII to Pb0 using a voltage of − 0.9 V, depositing and recovering 91.5% of Pb from the solution onto the electrode after 1 h of electrolysis. Intensification of process conditions were studied with recycling of the solvent: after the 1st pretreatment, the ionic liquid liquor was recycled and Pb was electrodeposited to clean-up and manage the build-up of metals for a subsequent pretreatment. The electrodeposition step in the ionic liquid liquor did not have a negative impact on the performance of the pretreatment and metal extraction was enhanced by 20% compared to recycled ionic liquid, which had not gone through any electrodeposition beforehand. This study opens up new valorisation possibilities for the integration of highly metal contaminated biomass into biorefining, without the need to incinerate metal contaminated biomass. • Miscanthus was grown on heavy metal marginal contaminated land, an exposed mine site in Wales. • Trace element analysis revealed high levels of Pb, Zn and other metals contaminants in the biomass. • The ionoSolv pretreatment process was used to both fractionate the lignocellulosic biomass into clean chemicals and extract the metals from the feedstock using a protic ionic liquid. • Pb was able to be electrodeposited from the ionic liquid liquor and the solvent was recycled for a subsequent pretreatment. [ABSTRACT FROM AUTHOR]

• For oligosaccharides production, SE and [C 2 mim][OAc] pretreatment is advised. • 90% (w/w) of initial biomass xylan dissolved to XOS via [C 2 mim][OAc] pretreatment. • Up to 50% glucan to GOS conversion using commercial endo -1,4-β-D-glucanases. • 33% extra profit for SE + [TEA][HSO 4 ] compared to [TEA][HSO 4 ] pretreatment. • XOS could contribute to economic viability of an integrated biorefining process. Pretreatment strategies are fundamental to effectively deconstruct lignocellulosic biomass and economically produce biofuels, biomaterials and bio-based chemicals. This study evaluated individual and combinatorial steam explosion (SE) and ionic liquid (IL) pretreatments for production of high-value oligosaccharides from a novel seed-based Miscanthus hybrid (Mx2779). The two ILs used for pretreatment were triethylammonium hydrogen sulphate [TEA][HSO 4 ] and 1-ethyl-3-methylimidazolium acetate [C 2 mim][OAc]. The results showed that each pretreatment leads to distinct effects on the fragmentation (cellulose and xylan dissolution, delignification, deacetylation) and physicochemical modification (cellulose and lignin properties) of lignocellulose. This, in turn, dictated enzymatic hydrolysis efficiencies of the cellulose pulp to glucose or gluco-oligosaccharides for downstream applications. Our findings suggest that the stand-alone SE or [C 2 mim][OAc] pretreatments may offer cost advantages over [TEA][HSO 4 ] through the production of oligosaccharides such as xylo- and gluco-oligosaccharides. This study also highlights technical and economic pretreatment process challenges related to the production of oligosaccharides from Miscanthus Mx2779 biomass. [ABSTRACT FROM AUTHOR]