The mitigation of climate change effects requires the use of alternative materials and technologies to control CO2 atmospheric levels through its capture, storage and use. In this field, the current work presents the evaluation of two poly(ionic liquid)s (PILs) (poly-1-vinyl-3-ethylimidazolium acetate and hydroxide) combined with free ionic liquid (IL) 1-butyl-3-methylimidolium acetate (BMI·OAc) for CO2 capture. The sorption capacity of PIL@IL composites was evaluated under 20 bar of CO2 at 298 K. Nuclear Magnetic Resonance (NMR) spectroscopy allowed quantification of CO2 sorption (physisorption and/or chemisorption) and in situ study of the PIL−CO2 interaction mechanism. NMR in combination with Molecular Dynamics (MD) simulations suggested a 3D organization of PIL composites, maintaining a similar organization to ILs. Also, the use of aqueous solutions of PIL@IL composites was tested, identifying the optimum conditions for water activation (intrinsic water trapped inside IL structure) for chemisorption. As our main contribution, we demonstrate the possibility to control the sorption pathway towards CO2 physisorption, or CO2 conversion (chemisorption) through carbonation (HCO3−/CO32-) according to the PIL/IL ratio, ions structure and water amount. The use of PIL/IL composites is a promising advance for further CO2 reuse approaching a biomimetic carbonation process.

The relationship between linear chain (ethylene oxide units) length of polymerisable monomers with morphology, electro-optical properties and 13C nuclear magnetic resonance (NMR) spectroscopy of the corresponding polymer-dispersed liquid crystal (PDLC) films was investigated. The preferred liquid crystal molecule alignment and permanent memory effect of PDLC were greatly influenced by the length of the molecular chain of prepolymers to be incorporated as a polymer matrix. By increasing the number of ethylene oxide in prepolymer chain and maintaining the number of functionalities (polymerisable groups in each monomer molecule), the permanent memory effect of PDLC increased, as proved by solid-state 13C NMR spectroscopy.

The fast and non-invasive detection of odors and volatile organic compounds (VOCs) by gas sensors and electronic
noses is a growing field of interest, mostly due to a large scope of potential applications. Additional drivers for the
expansion of the field include the development of alternative and sustainable sensing materials. The discovery
that isolated cross-linked polymeric structures of suberin spontaneously self-assemble as a film inspired us to
develop new sensing composite materials consisting of suberin and a liquid crystal (LC). Due to their stimuliresponsive and optically active nature, liquid crystals are interesting probes in gas sensing. Herein, we report
the isolation and the chemical characterization of two suberin types (from cork and from potato peels) resorting to
analyses of gas chromatography–mass spectrometry (GC-MS), solution nuclear magnetic resonance (NMR), and Xray photoelectron spectroscopy (XPS). The collected data highlighted their compositional and structural differences. Cork suberin showed a higher proportion of longer aliphatic constituents and is more esterified than potato
suberin. Accordingly, when casted it formed films with larger surface irregularities and a higher C/O ratio. When
either type of suberin was combined with the liquid crystal 5CB, the ensuing hybrid materials showed distinctive
morphological and sensing properties towards a set of 12 VOCs (comprising heptane, hexane, chloroform,
toluene, dichlormethane, diethylether, ethyl acetate, acetonitrile, acetone, ethanol, methanol, and acetic acid).
The optical responses generated by the materials are reversible and reproducible, showing stability for 3 weeks.
The individual VOC-sensing responses of the two hybrid materials are discussed taking as basis the chemistry of
each suberin type. A support vector machines (SVM) algorithm based on the features of the optical responses was
implemented to assess the VOC identification ability of the materials, revealing that the two distinct suberin-based
sensors complement each other, since they selectively identify distinct VOCs or VOC groups. It is expected that
such new environmentally-friendly gas sensing materials derived from natural diversity can be combined in arrays
to enlarge selectivity and sensing capacity.

Eco-sustainable and recyclable porous carbons are reported as metal-free catalysts for the synthesis of benzodiazepines for the first time. The porous carbons were able to efficiently catalyse the synthesis of benzodiazepine 1 from o-phenylendiamine 2 and acetone 3 under mild conditions. Both acidic functions and the porosity of the catalysts were determinant features. High conversion values were obtained when using HNO3 oxidized carbons. The highest selectivity to benzodiazepine 1 was obtained in the presence of the most microporous catalyst N-N, which is indicative of the great influence of porous properties. Stronger acid sites and high microporosity of the carbon treated with H2SO4 yield benzodiazepine 1 with total selectivity.

Background The awareness of environmental and socio-economic impacts caused by greenhouse gas emissions from the livestock sector leverages the adoption of strategies to counteract it. Feed supplements can play an important role in the reduction of the main greenhouse gas produced by ruminants—methane (CH\textsubscript{4}). In this context, this study aims to assess the effect of two biochar sources and inclusion levels on rumen fermentation parameters \textit{in vitro}. Methods Two sources of biochar (agro-forestry residues, AFB, and potato peel, PPB) were added at two levels (5 and 10%, dry matter (DM) basis) to two basal substrates (haylage and corn silage) and incubated 24-h with rumen inocula to assess the effects on CH\textsubscript{4} production and main rumen fermentation parameters \textit{in vitro}. Results AFB and PPB were obtained at different carbonization conditions resulting in different apparent surface areas, ash content, pH at the point of zero charge (pHpzc), and elemental analysis. Relative to control (0% biochar), biochar supplementation kept unaffected total gas production and yield (mL and mL/g DM, \textit{p} = 0.140 and \textit{p} = 0.240, respectively) and fermentation pH (\textit{p} = 0.666), increased CH\textsubscript{4}production and yield (mL and mL/g DM, respectively, \textit{p} = 0.001) and ammonia-N (NH\textsubscript{3}-N, \textit{p} = 0.040), and decreased total volatile fatty acids (VFA) production (\textit{p} < 0.001) and H\textsubscript{2} generated and consumed (\textit{p} ≤ 0.001). Biochar sources and inclusion levels had no negative effect on most of the fermentation parameters and efficiency. Acetic:propionic acid ratio (\textit{p} = 0.048) and H\textsubscript{2} consumed (\textit{p} = 0.019) were lower with AFB inclusion when compared to PPB. Biochar inclusion at 10% reduced H\textsubscript{2} consumed (\textit{p} < 0.001) and tended to reduce total gas production (\textit{p} = 0.055). Total VFA production (\textit{p} = 0.019), acetic acid proportion (\textit{p} = 0.011) and H\textsubscript{2} generated (\textit{p} = 0.048) were the lowest with AFB supplemented at 10%, no differences being observed among the other treatments. The basal substrate affected most fermentation parameters independently of biochar source and level used. Discussion Biochar supplementation increased NH\textsubscript{3}-N content, \textit{iso}-butyric, \textit{iso}-valeric and valeric acid proportions, and decreased VFA production suggesting a reduced energy supply for microbial growth, higher proteolysis and deamination of substrate N, and a decrease of NH\textsubscript{3}-N incorporation into microbial protein. No interaction was found between substrate and biochar source or level on any of the parameters measured. Although AFB and PPB had different textural and compositional characteristics, their effects on the rumen fermentation parameters were similar, the only observed effects being due to AFB included at 10%. Biochar supplementation promoted CH\textsubscript{4} production regardless of the source and inclusion level, suggesting that there may be other effects beyond biomass and temperature of production of biochar, highlighting the need to consider other characteristics to better identify the mechanism by which biochar may influence CH\textsubscript{4} production.

The work reports the impregnation of naproxen into locust bean gum mesoporous matrixes with different textural properties. The matrixes were prepared through the dissolution of the biopolymer in water and in two ionic liquids (ILs): [bmim][Cl] and [C2OHmim][Cl] and dried with scCO2. The poor water-soluble pharmaceutical drug naproxen was loaded into the matrixes and the composites were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy and by differential scanning calorimetry; the results were compared with neat ILs and drug. The naproxen release from the matrixes was attempted at pH 7.4. Sustained release of naproxen in the different composites occurs, and consequently the naproxen release has lower rates compared with neat crystalline naproxen dissolution. Nevertheless, it was possible to observe small differences on release profiles for the studied composites. The higher release rate was observed for the composite where [bmim][Cl] was used as solvent, for which the calorimetric analysis revealed full amorphization of the incorporated drug. Cytotoxicity assays reveal that cellular viability in Caco-2 cells is preserved. This fact allied with the biocompatibility of locust bean gum allow for the composites potential application as naproxen controlled/sustained delivery systems with higher drug bioavailability achieved through naproxen amorphization.

Lyotropic colloidal aqueous suspensions of cellulose nanocrystals (CNCs) can, after solvent evaporation, retain their chiral nematic arrangement. As water is removed the pitch value of the suspension decreases and structural colour-generating films, which are mechanically brittle in nature, can be obtained. Increasing their flexibility while keeping the chiral nematic structure and biocompatible nature is a challenging task. However, if achievable, this will promote their use in new and interesting applications. In this study, we report on the addition of different amounts of hydroxypropyl cellulose (HPC) to CNCs suspension within the coexistence of the isotropic-anisotropic phases and infer the influence of this cellulosic derivative on the properties of the obtained solid films. It was possible to add 50 wt.% of HPC to a CNCs aqueous suspension (to obtain a 50/50 solids ratio) without disrupting the LC phase of CNCs and maintaining a left-handed helical structure in the obtained films. When 30 wt.% of HPC was added to the suspension of CNCs, a strong colouration in the film was still observed. This colour shifts to the near-infrared region as the HPC content in the colloidal suspension increases to 40 wt.% or 50 wt.% The all-cellulosic composite films present an increase in the maximum strain as the concentration of HPC increases, as shown by the bending experiments and an improvement in their thermal properties.

Dodecamolydbophosphoric acid (HPMo) immobilized on USY zeolite was used as a catalyst for the acetalization of glycerol with pentanal at 70 °C. Catalysts were prepared with different amounts of heteropolyacid, and the most active sample was the HPMo2@Y catalyst (1.1 wt.%). The products of glycerol acetalization with pentanal were (2-butyl-1,3-dioxolan-4-yl)methanol, a five-member ring compound, and 2-butyl-1,3-dioxan-5-ol, a six-member ring compound. Good values of selectivity for the five-member ring compound (80–85%) were obtained with all materials. The reaction conditions were optimized using HPMo2@Y as a catalyst. The optimal conditions were determined to be 70 °C reaction temperature with 0.3 g catalyst and a 1:2.5 M ratio of glycerol to pentanal. The catalytic stability of HPMo2@Y was studied. The acetalization of glycerol with pentanal was performed using the same sample. High catalytic activity for HPMo2@Y was observed.

Abstract Anaerobic microorganisms of the Geobacter genus are effective electron sources for the synthesis of nanoparticles, for bioremediation of polluted water, and for the production of electricity in fuel cells. In multistep reactions, electrons are transferred via iron/heme cofactors of c-type cytochromes from the inner cell membrane to extracellular metal ions, which are bound to outer membrane cytochromes. We measured electron production and electron flux rates to 5×105 e s−1 per G. sulfurreducens. Remarkably, these rates are independent of the oxidants, and follow zero order kinetics. It turned out that the microorganisms regulate electron flux rates by increasing their Fe2+/Fe3+ ratios in the multiheme cytochromes whenever the activity of the extracellular metal oxidants is diminished. By this mechanism the respiration remains constant even when oxidizing conditions are changing. This homeostasis is a vital condition for living systems, and makes G. sulfurreducens a versatile electron source.

The monoheme outer membrane cytochrome F (OmcF) from Geobacter sulfurreducens plays an important role in Fe(III) reduction and electric current production. The electrochemical characterization of this cytochrome has shown that its redox potential is modulated by the solution pH (redox-Bohr effect) endowing the protein with the necessary properties to couple electron and proton transfer in the physiological range. The analysis of the OmcF structures in the reduced and oxidized states showed that with the exception of the side chain of histidine 47 (His⁴⁷), all other residues with protonatable side chains are distant from the heme iron and, therefore, are unlikely to affect the redox potential of the protein. The protonatable site at the imidazole ring of His⁴⁷ is in the close proximity to the heme and, therefore, this residue was suggested as the redox-Bohr center. In the present work, we tested this hypothesis by replacing the His⁴⁷ with non-protonatable residues (isoleucine – OmcFH47I and phenylalanine – OmcFH47F). The structure of the mutant OmcFH47I was determined by X-ray crystallography to 1.13 Å resolution and showed only minimal changes at the site of the mutation. Both mutants were ¹⁵N-labeled and their overall folding was confirmed to be the same as the wild-type by NMR spectroscopy. The pH dependence of the redox potential of the mutants was measured by cyclic voltammetry. Compared to the wild-type protein, the magnitude of the redox-Bohr effect in the mutants was smaller, but not fully abolished, confirming the role of His⁴⁷ on the pH modulation of OmcF’s redox potential. However, the pH effect on the heme substituents’ NMR chemical shifts suggested that the heme propionate P₁₃ also contributes to the overall redox-Bohr effect in OmcF. In physiological terms, the contribution of two independent acid–base centers to the observed redox-Bohr effect confers OmcF a higher versatility to environmental changes by coupling electron/proton transfer within a wider pH range.

Understanding the specific molecular interactions between proteins and β1,3-1,4-mixed-linked d-glucans is fundamental to harvest the full biological and biotechnological potential of these carbohydrates and of proteins that specifically recognize them. The family 11 carbohydrate-binding module from Clostridium thermocellum (CtCBM11) is known for its binding preference for β1,3-1,4-mixed-linked over β1,4-linked glucans. Despite the growing industrial interest of this protein for the biotransformation of lignocellulosic biomass, the molecular determinants of its ligand specificity are not well defined. In this report, a combined approach of methodologies was used to unravel, at a molecular level, the ligand recognition of CtCBM11. The analysis of the interaction by carbohydrate microarrays and NMR and the crystal structures of CtCBM11 bound to β1,3-1,4-linked glucose oligosaccharides showed that both the chain length and the position of the β1,3-linkage are important for recognition, and identified the tetrasaccharide Glcβ1,4Glcβ1,4Glcβ1,3Glc sequence as a minimum epitope required for binding. The structural data, along with site-directed mutagenesis and ITC studies, demonstrated the specificity of CtCBM11 for the twisted conformation of β1,3-1,4-mixed-linked glucans. This is mediated by a conformation–selection mechanism of the ligand in the binding cleft through CH-π stacking and a hydrogen bonding network, which is dependent not only on ligand chain length, but also on the presence of a β1,3-linkage at the reducing end and at specific positions along the β1,4-linked glucan chain. The understanding of the detailed mechanism by which CtCBM11 can distinguish between linear and mixed-linked β-glucans strengthens its exploitation for the design of new biomolecules with improved capabilities and applications in health and agriculture. Database Structural data are available in the Protein Data Bank under the accession codes 6R3M and 6R31.

Environment-friendly production of power and clean water is one of the major goals of 2030 Agenda for Sustainable Development, and can be achieved by emerging electromembrane processes, such as reverse electrodialysis (RED) and membrane capacitive deionisation (MCDI). RED generates electricity from salinity gradient energy sources, while MCDI desalinates (mainly) brackish water. However, fouling, scaling, stack channels clogging and undesired uphill ionic transport can reduce the power output and salt removal efficiency in RED and MCDI, respectively. A practical overview of current problems and challenges of operating and monitoring these processes under real conditions is provided. Appropriate mitigation approaches, which might include feed water pre-treatment, in-situ cleaning strategies and/or development of new antifouling ion-exchange membranes (IEMs) are disclosed. First, a description, analysis and (when possible) normalised comparison of the performance of available RED and MCDI stacks, employing natural saline streams, is presented. Afterwards, it is discussed how fouling formation can be detected, monitored and characterised, which is essential to implement effective pre-treatment and cleaning strategies. Finally, sustainable ways for preparation of appropriate IEMs are selected and presented.

Porous carbons from digestate-derived hydrochar were produced, characterized and their performance to reclaim phosphate from water was evaluated as a preliminary approach to demonstrate their practical application. In a first step, the digestate was converted into hydrochars through hydrothermal carbonization by using two different pH conditions: 8.3 (native conditions) and 3.0 (addition of H2SO4). The resulting hydrochars did not present significant differences. Consecutively, the hydrochars were activated with KOH to produce activated carbons with enhanced textural properties. The resulting porous carbons presented marked differences: the AC native presented a lower ash content (20.3 wt%) and a higher surface area (SBET = 1106 m2/g) when compared with the AC-H2SO4 (ash content = 43.7 wt% SBET = 503 m2/g). Phosphorus, as phosphate, is a resource present in significative amount in wastewater, causing serious problems of eutrophication. Therefore, the performance of the porous carbons samples to recover phosphate – P(PO43−) – from water was evaluated through exploitation assays that included kinetic studies. The lumped model presented a good fitting to the kinetic data and the obtained uptake capacities were the same for both carbons, 12 mg P(PO43−)/g carbon. Despite the poorer textural properties of AC-H2SO4, this carbon was richer in Ca, Al, Fe, K, and Mg cations which promoted the formation of mineral complexes with phosphate anions. The results obtained in this work are promising for the future development of P(PO43−) enriched carbons that can be used thereafter as biofertilizers in soil amendment applications.

This work reports the synthesis of kappa-carrageenan aerogels using different dissolution and crosslinking media in order to evaluate its effects on the textural properties of the matrixes and further on the drug loading and release performance. The different aerogel samples were produced through the dissolution of the biopolymer in water with addition of potassium salts as crosslinking agents and, in two different ionic liquids (ILs) derived from imidazolium ion, being further dried with supercritical CO2. The samples were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Nitrogen Adsorption-Desorption Analysis, Thermogravimetry (TGA) and Differential Scanning Calorimetry (DSC). The synthesized samples presented surface areas similar to the carrageenan aerogels being their structure constituted mainly by meso and macropores. The absence of ionic liquid in samples was demonstrated by DSC analysis and was corroborated by the cytotoxicity assays which revealed that cellular viability in Caco-2 cells was preserved. Tetracycline was used as a model drug and loaded in two of the prepared aerogels samples. The release experiments were performed with the composites to test in vitro drug release at physiologic pH. With a higher macroporosity, the kappa-carrageenan aerogel prepared by dissolution into ionic liquid showed a higher loading capacity than the one prepared by dissolution into water and a slightly higher release rate. The matrixes were considered to present a good potential to be used as biocompatible carriers on drug controlled delivery.

{Two new bis(aryl-imino)-acenaphthene, Ar-BIAN (Ar = 2

{The Keggin phosphotungstate (PW12) and its zinc derivative (PW11Zn) were tested as oxidative catalysts for desulfurization processes using simulated and real diesels. These compounds were used as homogeneous catalysts, while the corresponding SBA-15 composites were used as heterogeneous catalysts. The comparison of their catalytic performance demonstrated that the zinc-substituted polyoxo-metalate is more efficient than the plenary PW12 structure. Additionally, using the heterogeneous PW11Zn@aptesSBA-15, the sustainability and catalytic efficiency was largely improved, allowing the total sulfur removal from model diesel after 1 h using a small amount of oxidant (H2O2/S = 4) under an oxidative solvent-free system. The desulfurization of real diesels was performed under similar conditions, achieving 87.8% of efficiency using the PW11Zn@aptesSBA-15 catalyst. Furthermore, the catalyst maintained its activity over consecutive desulfurization cycles. The cost-effective operational conditions achieved with PW11Zn@aptesSBA-15 turn this into a promising material to be used in an industrial scale to treat diesel.}

Mesoporous silica nanoparticles (MSNs) strategically functionalized were used to immobilize a homogeneous polyoxomolybdate catalyst {[}PMo12O40](3-) (PMo12), active but unstable. The PMo12@TBA-MSN composite (where TBA refers to surface-tethered tributylammonium groups) conferred high stability to the polyoxomolybdate catalytic center and displayed an increase in efficiency for the oxidative desulfurization (ECODS) of a diesel simulant under sustainable conditions (using H2O2 as oxidant and an ionic liquid, {[}BMIM]PF6, as solvent). Continuous reuse of the catalyst and ionic liquid solvent in consecutive ECODS cycles was successfully performed, avoiding the production of residual wastes. The performance of the PMo12@TBA-MSN catalyst improved upon its reuse, leading to complete desulfurization of a multicomponent model diesel containing benzothiophene derivatives after just 1 h of the catalytic stage of the process. The robust nature of the supported catalyst was indicated by characterization of the recovered solid which showed retention of the structural and chemical integrities.

Strategic polyoxometalate Keggin-type structural modification was performed to increase the oxidative catalytic performance to desulfurize model and real diesels. The most active lacunar structure {[}PW11O39](7-) (PW11) showed to complete desulfurize a simulated diesel after 60 min at 70 degrees C. Its application as homogeneous catalyst using a biphasic system 1: 1 diesel/acetonitrile needed to use an excess of oxidant (ratio H2O2/S = 8). The immobilization of the PW11 on amine-functionalized SBA-15 supports originated two heterogeneous catalysts PW11@aptesSBA-15 and PW11@tbaSBA-15. The best results were attained with the PW11@aptesSBA-15 catalyst showing identical oxidative desulfurization performance as the homogeneous analogue. As advantage, this heterogeneous catalyst promotes the complete desulfurization of simulated diesel using a solvent-free system, i.e. without the need of acetonitrile use. On the other hand, the same desulfurization efficiency could be achieved using half the amount of oxidant (H2O2/S = 4). The oxidative desulfurization of the real diesel achieved a remarkable 83.4% of efficiency after just 2 h. The recycling capacity of PW11@aptesSBA-15 catalyst was confirmed for eight consecutive cycles using the biphasic and the solvent-free systems. Its stability investigation demonstrates to be higher under the solvent-free system than the biphasic system, without practically any occurrence of PW11 leaching in the first case. On the other hand, the Venturello peroxocomplex {[}PO4\{W(O-2)(2)\}(4)](3-), recognized as active intermediate in the homogeneous biphasic system, was not identified in the heterogeneous catalytic systems.