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AbstractAcid pretreatment of lignocellulosic biomass, required for bioethanol production, generates large amounts of by‐products, such as lignin and hydrolyzed hemicellulose fractions, which have found so far very limited applications. In this work, we demonstrate how the recovered hemicellulose hydrolysis products can be effectively utilized as a precursor for the synthesis of functional carbon materials through hydrothermal carbonization (HTC). The morphology and chemical structure of the synthesized HTC carbons are thoroughly characterized to highlight their similarities with glucose‐derived HTC carbons. Furthermore, two routes for introducing porosity within the HTC carbon structure are presented: i) silica nanoparticle hard‐templating, which is shown to be a viable method for the synthesis of carbonaceous hollow spheres; and ii) KOH chemical activation. The synthesized activated carbons (ACs) show an extremely high porosity (pore volume≈1.0 cm3 g−1) mostly composed of micropores (90 % of total pore volume). Because of their favorable textural properties, the ACs are further tested as electrodes for supercapacitors, yielding very promising results (300 F g−1 at 250 mA g−1) and confirming the high suitability of KOH‐activated HTC carbons derived from spruce and corncob hydrolysis products as materials for electric double layer supercapacitors.

4 figures, 6 tables.-- © 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ For the first time, this work addresses the hydrodeoxygenation (HDO) of lignocellulosic bio-oil over a carbon–neutral Mo2C/CNF catalyst for the production of liquid biofuels and value-added chemicals, thoroughly examining the effect of the temperature, initial H2 pressure, reaction time and catalyst/bio-oil ratio. These variables had a significant influence on the process, allowing the transformation of the original bio-oil into different fractions in varying yields, including an upgraded bio-oil (17–72%), a solid product (4–44%), an aqueous phase (5–39%) and a gaseous stream (1–15%). The upgraded bio-oil comprised a mix of phenols (56–78%), cyclic ketones (7–30%), carboxylic acids (2–8%), esters (0–9%) and aromatic compounds (0–20%). The relative amounts of C, H and O of this product shifted by 34–78 wt%, 3–8 wt% and 13–62 wt%, while its HHV ranged between 9 and 35 MJ/kg. Process optimisation revealed that using a temperature of 350 °C, an initial H2 pressure of 40 bar and 0.19 g cat/g bio-oil for 1 h, it was possible to convert 65% of the organic content of the bio-oil into a liquid bio-fuel with a HHV of 30 MJ/kg (twice the value of the original feedstock), which represents a deoxygenation degree of 70% and an energy efficiency of 62%. Besides, all the bio-oil organic content can be converted into a liquid product with a high proportion of phenols (79%) at 250 °C, applying an initial H2 pressure of 20 bar and 0.14 g cat/g bio-oil for around 0.5 h. This liquid can be used as a sustainable phenolic-rich antioxidant additive as well as a bio-based source of aromatic compounds. Therefore, these results are a step forward in the biomass conversion over carbon–neutral catalysts. This work was funded by FEDER and the Spanish Economy and Competitiveness Ministry (ENE 2017-83854-R). Javier Remón and Jesús Gracia would like to express their gratitude to the “Ministerio de Ciencia, Innovación y Universidades” for their JdC (FJCI-2016-30847 and IJC2018-037110-I) and FPI (PRE2018-085182) fellowships, respectively awarded. Peer reviewed

Belite cements, BCs, containing mainly belite, alite and calcium aluminates, are currently used as low heat cements. These binders produce high amounts of C–S–H gel and have very good durability properties which are reviewed. Additional advantages include: (i) lower limestone demand, with lower associated CO2 emissions; (ii) lower energy demand; (iii) lower kiln operating temperature, which means lowering CO2 and NOx emissions from fuel burning; and (iv) lower temperature increase at early hydration age. However, early-age strength developments are not competitive with those of Portland cements. Hence, to improve their early-age strength developments is a research priority known as activation. This enhancement can be attained by three compatible approaches: (i) chemical, (ii) physical; and (iii) admixture activations. The current research status for BCs activation is reviewed including: cost-effective element substitutions to stabilize high-temperature forms; fast cooling, milling and mild temperature hydration as physical activation; and the use of C–S–H seeds as admixture activation. After discussion of the resulting microstructures, a research outlook is exercised. The work in Malaga has been supported by BIA2017-82391-R research grant, which is co-funded by FEDER. The work in San Sebastian was supported by PID2019-105488GB-I00 research grant, the Gobierno Vasco UPV/EHU (Project No. IT-1246-19), and the EIG CONCERT-Japan 5th Joint Call on Functional Porous Materials (Project No. PCI2019- 103657-POROPCM). We thank Buzzi Unicem for providing us with more than 30 kg of a large-scale production of an active belite cement. We also thank Fulvio Canonico (Buzzi Unicem) for very helpful discussions about industrial aspects of belite cements.

Food waste generated at the consumer level constitutes a gigantic portion of the total amount of food wasted/lost and valorisation is touted as the most sustainable way of managing the generated waste. While food waste valorisation encompasses several methods, composting is the cheapest technique that can produce stabilised carbon-rich soil amendments. The food waste generated at the consumer level, however, is laden with sodium chloride. The compost produced from such waste has the potential of inducing saline and or sodic conditions in the soil, resultantly impeding proper crop growth and yield. Due to the scarcity of plausible means of eradicating sodium chloride from the food waste before composting, the idea of mixing the composted food waste with other low sodium chloride-containing composts to produce a food waste compost-containing amalgam with a high fertiliser potential was mulled in this study. The study then assessed the effects of mixing sodium-chloride-rich food waste compost with the nutritious and low sodium chloride-containing livestock manure composts on the yield and quality of leaf lettuce. Mixing food waste compost with livestock manure composts in the right proportions created mixed composts that produced a higher lettuce yield than both the pure livestock manure composts and food waste compost. The mixed composts also produced leaf lettuce with higher chlorophyll content and, thus, better marketability and lower nitrate content (with higher health value) than the pure livestock manure composts.

This work reports the oxidation behaviour and waste-to-energy output of different semi-rigid and flexible aluminium packagings when incinerated at 850°C in an air atmosphere enriched with 6% oxygen, in the laboratory setting. The physical properties of the different packagings were determined, including their metallic aluminium contents. The ash contents of their combustion products were determined according to standard BS ISO 1171:2010. The net calorific value, the required energy, and the calorific gain associated with each packaging type were determined following standard BS EN 13431:2004. Packagings with an aluminium lamina thickness of >50μm did not fully oxidise. During incineration, the weight-for-weight waste-to-energy output of the packagings with thick aluminium lamina was lower than that of packagings with thin lamina. The calorific gain depended on the degree of oxidation of the metallic aluminium, but was greater than zero for all the packagings studied. Waste aluminium may therefore be said to act as an energy source in municipal solid waste incineration systems.

The financial support for this work was provided by the Plan Nacional, Ministerio de Economía y Competitividad of Spain: PN (MINECO), under the Project CTM2014-58435-C2-1-R.

There are different technologies to optimize the use of solar energy in construction systems, with the aim of improving the building energy efficiency and also to reduce the effect of solar radiation on the exterior coatings, which in turn affects the urban areas warming. Among these technologies, chromogenic devices based on materials whose optical properties can be reversibly modified by some external stimulus have become relevant. These materials are especially interesting because they adapt to variations of solar radiation during the day and throughout the different seasons of the year. The facade coating may have different types of texture or color, which determine specific optical properties. One of these properties is the absorptance, which determines the amount of solar radiation absorbed by the material with respect to the incident radiation. The effect of the absorptance on the building energy demand will be conditioned by other parameters that also influence it, such as the climatic zone, orientation and thermal properties of the wall. In the work presented, the influence of the optical properties of three types of exterior facade coating on the building energy demand is analyzed. The materials chosen for this study are a conventional white Portland cement, a belitic cement synthesized in the laboratory by a process of low energy and low CO2 emissions and a brick representative of a brickwork wall, presenting the first two a more polished finish and clearer colors than the second. The final objective of this study is to determine the parameters that optimize the utilization of the optical properties of the studied coatings in the building energy efficiency.