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Impact of stabilisers on the catalytic performance of supported Au colloidal nanoparticles for the liquid phase oxidation of glucose to glucaric acid.

The main constraint on developing a full potential for CO2 adsorption of 3D composite monoliths made of reduced graphene oxide (rGO) and polymer materials is the lack of control of their textural properties, along with the diffusional limitation to the CO2 adsorption due to the pronounced polymers' microporosity. In this work, the textural properties of the composites were altered by employing highly crosslinked polymer particles, synthesized by emulsion polymerization in aqueous media. For that aim, waterborne methyl methacrylate (MMA) particles were prepared, in which the crosslinking was induced by using different quantities of divinyl benzene (DVB). Afterward, these particles were combined with rGO platelets and subjected to the reduction-induced self assembly process. The resulting 3D monolithic porous materials certainly presented improved textural properties, in which the porosity and BET surface area were increased up to 100% with respect to noncrosslinked composites. The crosslinked density of MMA polymer particles was a key parameter controlling the porous properties of the composites. Consequently, higher CO2 uptake than that of neat GO structures and composites made of noncrosslinked MMA polymer particles was attained. This work demonstrates that a proper control of the microstructure of the polymer particles and their facile introduction within rGO self assembly 3D structures is a powerful tool to tailor the textural properties of the composites toward improved CO2 capture performance. I.B. gratefully acknowledges the financial support of the Spanish Government (BES-2017-080221). L.S. thank s the grant P20_00328 funded by the Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades of the Junta de Andalucia and by the EU FEDER funds. The authors thank the technical and human support provided by SGIker (UPV/EHU/ERDF, EU).

Different series of Au on carbon catalysts were prepared via sol-immobilization to investigate the role of polymers (polyvinylpyrrolidone PVP, polyethylene glycol PEG and polyvinyl alcohol PVA), employed as gold nanoparticle (NP) stabilizers, on catalyst properties and on catalytic activity. The synthesized materials were widely characterized with several techniques (DLS, XRD, TEM and XPS) and used as catalysts in the 5-hydroxymethylfurfural (HMF) oxidation to produce 2,5-furandicarboxylic acid (FDCA). The obtained results clearly demonstrated the PVA leading to the formation of smaller and more active NPs. On the contrary, polyethylene glycol was shown to affect gold exposure and, as a consequence, to reduce the catalyst activity due to steric effects while PVP-based catalysts presented bigger and more covered Au NPs. The investigation on the reusability of the catalysts demonstrated the presence of a significant deactivation on all prepared materials, but the presence of higher amounts of polymer seems to have a positive effect on catalyst stability even if associated with lower reactivity. Computational studies have provided interesting information on the NP-polymer interactions and consequently on the catalytic activities.

In most current processes aimed at producing biodiesel glycerol is still a co-product, and its valorisation is essential for the biorefinery. This work relies on previous results showing the dependence of the selective dehydration of glycerol to acetol (hydroxyacetone) on achieving a moderate acidity and the redox functionality of copper to complete the chemical process. In this sense, this reaction was studied using CuO supported on silica. Different silicas and copper incorporation methodologies were investigated to develop the best CuO/SiO material. Interestingly, these CuO-based materials developed acidity and became more active when increasing the copper oxide dispersion, thereby going from poorly to intensely effective to dehydrate glycerol selectively to acetol. Catalysts were characterised by different techniques (i.e., ICP, N adsorption, XRD, TPR, HR-TEM, etc.) to explain the differences observed in catalytic activity and acetol yield based on their physicochemical properties., Financial support by Spanish Government (CTQ-2015-67592, PGC2018-097277-B-I00 and SEV-2016-0683) is gratefully acknowledged. J.M. thanks Spanish Government (CTQ-2015-67592) for the Ph.D. fellowship. Authors also thank Miriam Parreño Romero and the Electron Microscopy Service of Universitat Politècnica de València for their support.

The synthesis of PCH from natural bentonite produces a porous heterostructure material effective for the adsorption of glyphosate from water. The adsorption process takes place through an interaction between the silanol group of montmorillonite and/or the PCH adsorbent with the functional groups of glyphosate. The glyphosate adsorption isotherms, recorded for all the studied samples, have been established to be of Langmuir type. The kinetic of the herbicide adsorption on the PCH was best described by the pseudo-second-order model. With the increase in temperature from 25 to 50 °C, the sorption capacities of the materials studied towards glyphosate increased. The process of glyphosate adsorption was found to be endothermic and spontaneous in nature, as indicated by positive values of ΔH and negative values of ΔG. According to the results obtained, the herbicide sorption was more effective in a basic environment. The maximum amount of adsorbed glyphosate is almost doubled with PCH from 13.5 mg/g of natural clay to 27.5 mg/g of PCH. This study was partially funded by project RTI2018-099668-BC22 of Ministerio de Ciencia, Innovación y Universidades, and project UMA18-FEDERJA-126 of Junta de Andalucía and FEDER funds. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature and Funding for open access charge: Universidad de Málaga / CBUA.

Herein, a family of Mg/Al hydrotalcites was synthesized as catalytic precursors of MgAlOx mixed oxides. Both hydrotalcites and mixed oxides were characterized and the mixed oxides were tested in the reduction of furfural to yield furfuryl alcohol by MPV reaction using isopropanol as hydrogen donor. Different catalytic parameters were tested, such as the type of alcohol, calcination temperature of the hydrotalcite, and reaction temperature. Furfural and isopropanol were adsorbed on the MgAl-3 catalyst to follow the species adsorbed on the catalyst by FTIR analysis. The results showed that the isopropanol was activated as isopropoxide and furfural changed the adsorption site with increasing temperature but maintaining the h1-conformation. The catalytic performances were associated with the basicity of the catalysts and the deactivation processes have been attributed to the existence of adsorbed species on the surface, mainly due to furfural-derived compounds. The catalysts were reused in three consecutive cycles showing a sharp drop of catalytic activity. To recover the activity, the catalysts were calcined at 500 °C but the activity was only partially recovered. The XPS analysis after reactivation showed that the catalyst surface was modified due to the segregation of hydroxides of Mg and Al.

Since the beginning of civilization, porous materials have been used for medical purposes [...]

Three chitosans with different morphologies have been used (commercial chitosan powder, chitosan in film form and chitosan in globular form synthesized by the freeze-dried method) for the synthesis of biochars. The pyrolytic treatment has revealed that the biochar synthesized from the chitosan formed by the freeze-dried method reaches the highest CO

A corrosion study of high purity magnesium in two simulated physiological solutions (Ringer’s solution and Hank’s solution) is reported. The electrochemical behavior of pure magnesium rotating disc electrode (RDE) was examined using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques. The rotation affects the potentiodynamic polarisation curves and makes a shift in the anodic branches because of the dissolution of the corrosion layer. The EIS results showed the presence of three-time constant attributed to formation of the protective film on the Mg surface, the faradic process and the adsorption phenomena. The formation of a compact layer on magnesium surface, offers a higher corrosion protective ability for Mg. The thickness of this layer increase subsequently with increase in immersion time. The magnesium surface morphology was characterized by scanning electron microscopy (SEM). The composition and the microstructure of the corrosion product film were carried out using X-ray photoelectric spectroscopy (XPS) and X-ray diffraction (XRD). Brucite, calcite and magnesium calcite were detected in both medium, while aggregated particles containing a high concentration of phosphorus were formed on Mg in Hunk’s solution.

The competitiveness of the biodiesel industry may be improved by adding value through co-products and integration with the oleochemical industry, especially for novel products such as biolubricants, a product of increasing world demand. In this study the synthesis of biolubricants from soybean oil was evaluated using transesterification, epoxidation and oxirane ring opening reactions. Water, 2-ethylhexanol and their mixtures were used to obtain hydroxyl-rich and/or ether-type branched molecules. All chemical modifications were monitored by Nuclear Magnetic Resonance (1H NMR) and evaluated through the physicochemical properties of the products. Several potential biolubricant samples were synthesized with viscosities at 40 °C ranging from 26.6 to 99.6 cSt, viscosity index from 26 to 139, densities at 20 °C from 0.925 to 0.964 g/cm3, and pour points from −3 to −12 °C. From these results, a proposal of a feasible industrial process for the production of biolubricants from soybean oil is presented, consisting of 16 units, of which 15 may be integrated with an existing biodiesel plant.

A series of Co supported on Al-modified SBA-15 catalysts has been studied in the gas phase direct transformation of levulinic acid (LA) into ethyl valerate (EV) using a continuous fixed-bed reactor and ethanol as solvent. It was observed that once the intermediate product gamma-valerolactone (GVL) has been formed, the presence of aluminum is required for the selective transformation to EV. Three Lewis acid sites (LAS) are identified (from highest to lowest acid strength): aluminum ions in tetrahedral and octahedral coordination and Co2+ sites. The intrinsic activity of these LAS for the key reaction, the GVL ring opening, decreases with the strength of these acid sites, but so does the undesirable formation of coke, also catalyzed by these centers. The best catalyst was that with the highest Al content, CoSBA-2.5Al, that reached an EV yield of up to 70%. This result is associated with the presence of LAS attributed to the presence of Co2+ surface species that, although having low intrinsic activity in the selective GVL ring-opening reaction, are highly concentrated in this sample and also possess less activity in the undesirable and deactivating formation of coke. These Co2+ LAS have been stabilized by incorporation of aluminum into the support, modifying the reducibility and dispersion of cobalt species. Additionally, the lower proportion of metallic Co species decreases the hydrogenating capacity of this catalyst. This decrease is a positive result because it prevents GVL hydrogenation to undesired products. This catalyst also showed promising stability in a 140 h on-stream run.

A series of tetrametallic hydrotalcite with different Ni loading, were synthesized by coprecipitation method. Then, these hydrotalcites were calcined in their respective metal oxides and were used as catalysts in the etherification reaction for the synthesis of polyglycerols. The effect of Ni loading on the structural and textural features was investigated by various techniques such as X-ray diffraction (XRD), thermogravimetric analysis TG–DSC–MS, temperature-programmed reduction (H2-TPR), temperature-programmed desorption (NH3-TPD) and 1-butene isomerization as a model reaction to probe acid–base character of catalysts. Mixed oxides derived from hydrotalcites are found to be active and suitable, via solvent free, in the glycerol etherification reaction. A gradual enhance of glycerol conversion is revealed when increasing the Ni/Mg molar ratio and the most active catalyst found is HTc-Ni75% with full selectivity to diglycerol.

Olive stones were employed as feedstock for furfural production in two stages: 1) autohydrolysis of hemicellulosic fraction to recover their pentoses, mainly xylose, and 2) subsequent dehydration of pentoses into furfural. Autohydrolysis step was optimized by using different experimental conditions (temperature: 160-200 ºC and time: 30-75 min), giving rise to liquors with different xylose concentrations, since hydrolysis was incomplete in some cases. The combined use of a commercial γ-Al2O3 and CaCl2 led to total hydrolysis of non-hydrolyzed pentosans after autohydrolysis step, and the subsequent dehydration of pentoses into furfural. The maximum values of furfural yield and efficiency were 23 and 96%, respectively, after only 60 minutes at 150 ºC by using liquor obtained by autohydrolysis at 180 ºC and 30 min (L5.1) as source of pentoses. This liquor, L5.1, provided better catalytic results than other liquors which had shown higher xylose concentration after autohydrolysis, probably due to these latter also exhibited a higher concentration of organic acids; thus, the presence of organic acids such as acetic and lactic acid could promote side undesired reactions leading to lower furfural yields. Finally, γ-Al2O3 was more effective for furfural production under these experimental conditions than other solid acid catalysts, such as mesoporous Nb2O5, Nb-doped SBA-15 and Zr-doped HMS silicas, probably due to alumina has a higher density of acid sites. Spanish Ministry of Economy and Competitiveness (RTI2018-94918-B-C44 project), Junta de Andalucía (RNM-1565), FEDER (European Union) funds (UMA18-FEDERJA-171) and Malaga University. C.G.S. and J.A.C. thank to FEDER funds and Malaga University respectively for financial support. L.S.C. gratefully acknowledges support from Spanish MINECO via the concession of a Ramon y Cajal contract (RYC-2015-17109).

Monolithic nanocarbon-based CO2 solid sorbents offer fast mass transport, easy handling, minor pressure drop and cycle operation stability due to the interconnected three-dimensional network of por...

In the present study a series of Au–transition metal oxides supported on a clay mineral such as sepiolite were tested in the preferential oxidation of CO in an excess of H2 under simulated solar light irradiation and in the absence of light, at 30 °C and atmospheric pressure. Transition metal oxides (ZnO, Fe2O3, NiO, MnO2, and Co3O4) were dispersed over the sepiolite surface where, subsequently, Au nanoparticles with an average particle size between 2 and 3 nm were successfully deposited–precipitated. The obtained photocatalysts were characterized by XRD, XRF, DRUV-Vis, N2 adsorption–desorption and HRTEM in order to evaluate the optical, structural and chemical properties of the prepared samples. Despite the low amount of gold (nominal 1.0 wt%), the catalysts exhibited an outstanding behavior under light irradiation, with reaction rates between 4.5 and 5.2 mmol COox gcat−1 h−1 for the Au–NiSep, Au–CoSep and Au–ZnSep samples. These photocatalysts exhibited a high dispersion of the respective transition metal oxides over the sepiolite support and the presence of low-coordinated hemispherical gold nanoparticles. The superior photocatalytic efficiency of these samples was ascribed to the reduction of the electron–hole pair recombination of photogenerated charge carriers by the excitation of the localized surface plasmon resonance of the Au nanoparticles. The BET surface area and the gold particle size seemed to be relevant factors affecting the catalytic performance.

Hollow microspheres of silica were synthesized with different ethanol/water ratios (0.4, 1.0, 2.0 and 6.0) to assess the influence of this parameter on the morphology/porosity of the samples and thus on their water adsorption capacity. The samples were characterized by N2 at 77 K and CO2 at 273 K adsorption isotherms, scanning electron microscopy, transmission electron microscopy and water vapor isotherms at 298, 313 and 328 K. The textural properties of the samples were slightly different: as the ethanol/water ratio increases, the pore volume and specific surface area decrease and the structure of the samples evolves into a well-defined spherical arrangement. In addition, water adsorption capacity of the samples was similar to that of commercial adsorbents used for gas drying at high relative pressures, but significantly lower at low relative pressures. Moreover, varying of the ethanol/water ratio did not lead to a noticeable improvement in the water adsorption capacity at low relative pressures and hence these samples are not suitable for deep gas drying. On the other hand, as they require less energy to be regenerated, HMS are alternatives to be considered in less demanding situations, such as coarse drying and water harvesting from air.

Currently, there is a great interest in the development of sustainable and green technologies for production of biofuels and chemicals. In this sense, much attention is being paid to lignocellulosic biomass as feedstock, as alternative to fossil-based resources, inasmuch as its fractions can be transformed into value-added chemicals. Two important platform molecules derived from lignocellulosic sugars are furfural and levulinic acid, which can be transformed into a large spectrum of chemicals, by hydrogenation, oxidation, or condensation, with applications as solvents, agrochemicals, fragrances, pharmaceuticals, among others. However, in many cases, noble metal-based catalysts, scarce and expensive, are used. Therefore, an important effort is performed to search the most abundant, readily available, and cheap transition-metal-based catalysts. Among these, copper-based catalysts have been proposed, and the present review deals with the hydrogenation of furfural and levulinic acid, with Cu-based catalysts, into several relevant chemicals: furfuryl alcohol, 2-methylfuran, and cyclopentanone from FUR, and γ-valerolactone and 2-methyltetrahydrofuran from LA. Special emphasis has been placed on catalytic processes used (gas- and liquid-phase, catalytic transfer hydrogenation), under heterogeneous catalysis. Moreover, the effect of addition of other metal to Cu-based catalysts has been considered, as well as the issue related to catalyst stability in reusing studies.

The adsorption of greenhouse gases (GHG) as a method to reduce their emissions into the atmosphere is an alternative that is easier to implement industrially and cheaper than other existing technologies, such as chemical capture, cryogenic separation, or membrane separation. The vast majority of works found in the literature have focused their efforts on capturing CO2 as it is the largest GHG. However, although N2O emissions are not as large as CO2, the impact that N2O has on the stratosphere and climate is much larger in proportion, despite which there is not much research on N2O capture. Since both gases are usually emitted into the atmosphere together (along with other gases), it is necessary to design selective adsorbents capable of capturing and separating these gases from each other and from other gases, to mitigate the effects of climate change. This review aims to compile the existing information to date on porous adsorbents, the characteristics of the N2O adsorption processes and, above all, aims to focus the reader’s gaze on the importance of designing selective adsorbents for greenhouse gas mixtures.

Typical porous silica (SBA-15) has been modified with pore expander agent (1,3,5-trimethylbenzene) and fluoride-species to diminish the length of the channels to obtain materials with different textural properties, varying the Si/Zr molar ratio between 20 and 5. These porous materials were characterized by X-ray Diffraction (XRD), N2 adsorption/desorption isotherms at −196 °C and X-ray Photoelectron Spectroscopy (XPS), obtaining adsorbent with a surface area between 420–337 m2 g−1 and an average pore diameter with a maximum between 20–25 nm. These materials were studied in the adsorption of human blood serum proteins (human serum albumin—HSA and immunoglobulin G—IgG). Generally, the incorporation of small proportions was favorable for proteins adsorption. The adsorption data revealed that the maximum adsorption capacity was reached close to the pI. The batch purification experiments in binary human serum solutions showed that Si sample has considerable adsorption for IgG while HSA adsorption is relatively low, so it is possible its separation.

Mesoporous silica SBA-15 solids have been synthesized at different aging temperature with the goal of obtaining materials with different textural properties. The synthesized samples have been evaluated for their CO2 adsorption capacity. In order to increase the CO2 adsorption capacity and the CO2/N2 selectivity, the SBA-15 synthesized at different aging temperatures were functionalized via grafting with 3-aminopropyltriethoxysilane (APTES) and via impregnation with polyethyleniminethylenediamine branched (PEI) or tetraethylenepentamine (TEPA). In all cases, the adsorption isotherms of the amine functionalized silica are fitted to the Dualsite-Langmuir model, where physical and chemical adsorption sites are reported. The isotherms reveal that grafted-silicas with APTES displayed the coexistence of both adsorption sites, while the adsorption process of PEI or TEPA impregnated-silicas are mainly governed by chemical interactions. The adsorption isotherms show that the most promising adsorbent for CO2 capture in terms of CO2 adsorption capacity and CO2/N2 selectivity is the SBA synthesized at 393 K (aging temperature) and functionalized with TEPA (50 wt%) (SBA-393-50T). This sample reached a CO2 adsorption capacity of 2.83 mmol g−1 at 100 kPa and 338 K. The CO2 adsorption capacity of this material decreased around 5% after the first adsorption/desorption cycle, maintaining a constant value for successive cycles. SBA-393-50T also showed an outstanding CO2/N2 selectivity, increasing significantly as the CO2 concentration decreases.

Nickel-based catalysts supported on sepiolite catalysts, with a nickel loading between 1 and 10 wt%, have been synthesized by several synthetic strategies (precipitation-deposition, impregnation and grafting-complexation) and subsequent calcination and reduction. The catalysts were characterized by H2 thermoprogrammed reduction (H2-TPR), X-ray diffraction, transmission electron microscopy, N2 adsorption–desorption at − 196 °C, NH3 thermoprogrammed desorption (NH3-TPD) and CO chemisorption. FUR hydrogenation in gas-phase revealed that the most active catalyst was the catalyst synthesized by the grafting-complexation method due to its highest metallic surface area and smallest metal crystal size, reaching a FUR yield close to 85% after 5 h of time-on-stream (TOS) at 190 °C, using a H2:FUR molar ratio of 11.5 and a WHSV of 1.5 h−1. Furan (F), methylfuran (MF) and furfuryl alcohol (FOL); however, the selectivity towards F and MF tend to decrease with the TOS, while FOL selectivity increases.

A series of Ni-MgO catalysts (Ni/Mg molar ratio: 0.1–0.3), prepared by a coprecipitation-calcination-reduction methodology, was characterized and evaluated in the gas-phase hydrogenation of furfural. In all cases, after reduction at 500 °C, nickel species were present as very tiny metal Ni(0) nanoparticles and forming part as Ni(II) of a NiO-MgO solid solution, as inferred from XRD and XPS techniques. The decarbonylation process of furfural was favored at reaction temperatures as low as 190 °C. The most active catalyst was that with a Ni/Mg molar ratio of 0.25, maintaining a furfural conversion of 96% after 5 h of time-on-stream at 190 °C, by feeding a furfural solution in cyclopentylmethyl ether (5 vol % furfural) under a H2 stream (H2:furfural molar ratio = 11.5 and WHSV = 1.5 h–1). Furan was the main product, with a yield of 88%, whereas furfuryl alcohol was formed at lower reaction temperature and shorter contact time. However, the catalyst suffers a gradual deactivation during a catalytic test of 24 ...

A series of Pd-based catalysts was prepared by incipient wetness impregnation over different acidic supports: amorphous SiO2-Al2O3, ZSM5 and beta zeolites. In addition to the effect of the support, other variables like the metal loading (0, 1, 2 and 4 wt%) on ZSM5 were tested in the direct conversion of levulinic acid (LA) to valeric biofuels (valeric acid/ester). The best result, a 92% yield of valeric biofuels, was obtained for a 2 wt% Pd supported on ZSM5 catalyst (2PdZSM5) after 8 h of reaction at 240 °C. Characterization techniques such as FTIR spectroscopy (using deuterated acetonitrile and CO as probe molecules), TEM and XPS were employed to explain this catalytic performance. FTIR spectra with deuterated acetonitrile evidenced the moderate acidity (in terms of concentration and strength) of the 2PdZSM5 catalyst, a desirable feature for the proper realization of this reaction. It has been observed that the acidity of the support favors the Pd dispersion, but it is less relevant for its catalytic properties. Finally, the stability of a representative catalyst was demonstrated under flow conditions for over 90 h, obtaining moderate but stable yields for the 2PdZSM5 catalyst.

The oxidative condensation of furfural and ethanol has been studied using supported gold colloidal nano particles. The influence of the nature of stabilizer (polyvinylalcohol, polyvinylpyrrolidone), the choice of thermal treatment and washing for removing the stabilizer, on the catalytic performance has been evaluated. Variation of the mean gold particle size and surface coverage of the gold nanoparticles onto the support surface were achieved by modifying the stabilizer to Au weight ratio. Thus, the mean gold particle size was varied in the range of 3-8 nm. The catalytic results showed that the choice of stabilizer, the stabilizer to Au weight ratio, thermal treatment of the catalyst, affect catalytic activity and selectivity/yield to the desired products. When PVA was the chosen stabilizer, the highest yield to furan-2-acrolein (33%) was attained with a PVA to Au weight ratio of 2.4. On the contrary, when PVP was the stabilizer, the best catalytic performance was achieved in its absence, with the yield of furan-2-acrolein reaching 21%. These results showed the strong impact of stabilizer to control catalytic activity and to enhance, in the case of PVA, the yield to the target product, whereas a strong negative effect was observed with PVP. Moreover, a mild thermal treatment of the catalyst and a washing step for the removal of the stabilizer from the catalyst had a positive effect on the catalytic performance.

The effect of polyvinyl alcohol (PVA) stabilizers and gold nanoparticles supported on active carbon (AuNPs/AC) was investigated in this article. Polymers with different molecular weights and hydrolysis degrees have been synthesized and used, like the stabilizing agent of Au nano-catalysts obtained by the sol-immobilization method. The reduction of 4-nitrophenol with NaBH4 has been used as a model reaction to investigate the catalytic activity of synthesized Au/AC catalysts. In addition, we report several characterization techniques such as ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) in order to correlate the properties of the polymer with the metal nanoparticle size and the catalytic activity. A volcano plot was observed linking the catalytic performance with hydrolysis degree and the maximum of the curve was identified at a value of 60%. The Au:PVA-60 weight ratio was changed in order to explain how the amount of the polymer can influence catalytic properties. The effect of nitroaromatic ring substituents on the catalytic mechanism was examined by the Hammett theory. Moreover, the reusability of the catalyst was investigated, with little to no decrease in activity observed over five catalytic cycles. Morphological and kinetic studies reported in this paper reveal the effect of the PVA polymeric stabilizer properties on the size and catalytic activity of supported gold nanoparticles.

The depletion of the fossil fuels has led to the search for and development of more sustainable and environmental benign energy source. In this sense, the biomass has emerged as alternative resource since biomass is the only source from which it is possible to obtain energy and mainly chemicals that, currently, are obtained from the traditional fossil fuels. The selection of the biomass source is a key parameter to reach a sustainable process. Considering these premises, the lignocellulosic biomass has emerged as a potential alternative source due to its non-edible character as well as its high availability throughout the Earth. Traditionally, the lignocellulosic biomass has been treated thermochemically to obtain high value-added products and energy. However, in the recent past, the microbial treatment of the lignocellulosic biomass has emerged as efficient methodology to solve the problems of energy shortage and the synthesis of valuable products. The aim of this chapter is to evaluate the metabolic process involved in the microbial degradation of lignocellulosic biomass as well as highlight the valuable products obtained through this microbial treatment by alcoholic fermentation and anaerobic digestion.

Clay minerals are the most abundant minerals on the surface of Earth [...]

Porous SiO2 nanospheres have been modified with different proportion of ZrO2 to obtain catalysts with Si/Zr molar ratio between 2.5 and 30. These materials were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N2 adsorption-desorption at -196 ºC, X-ray photoelectron spectroscopy and pyridine and 2-6-dimethylpyridine thermoprogrammed desorption. The characterization of these catalysts reveals that the incorporation of a high proportion of Zr favors the formation of Lewis acid sites, which are implied in catalytic transfer hydrogenation processes, whereas the low Brönsted acidity promote dehydration reaction, in such a way that it is possible to obtain a wide range of products from FUR through consecutive reactions, such as furfuryl alcohol, i-propyl furfuryl ether, i-propyl levulinate and γ-valerolactone in a range of temperature of 110-170 ºC between 1-6 h of reaction. Spanish Ministry of Science, Innovation and Universities:RTI2018‐94918‐B‐C44; FEDER (European Union) funds: RTI2018‐94918‐B‐C44 and UMA18-FEDERJA-171; University of Malaga; Junta de Andalucía; Funding for open access charge: Universidad de Málaga/CBUA

The monolithic materials of reduced graphene oxide (rGO) can be used successfully in CO2 adsorption. Here, the incorporation of CeO2 particles with and without polymer brushes grafted from the particles showed that the structural properties could be changed, affecting the adsorption of CO2. Polymer brushes of (1) poly(acrylic acid) (PAA), (2) poly(vinyl caprolactam) (PVCL) and (3) poly[(2-(methacryloyloxy)ethyl) trimethylammonium chloride] (PMETAC) were grafted from CeO2 via reversible addition−fragmentation chain transfer (RAFT) polymerization. The preparation of monoliths of rGO with different modified CeO2 particles led to different thermal properties (TGA), structural changes (BET isotherms) and CO2 adsorption. The responsive character of the CeO2@polymer was proven by the DLS and UV results. The responsive character of the particles incorporated into the rGO monolith affected not only the adsorption capacity but also the microstructure and values of the surface volume of the pores of the monolith. Monoliths with porosity values for better adsorption were affected by the responsive character of the polymer. This research was funded by the Basque government, grant number GV IT999-16.