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This work investigated the catalytic high-pressure CO

Pollution associated to marine plastic litter is raising increasing concerns due to its potential harmful effects on human health, biota, and coastal ecosystems. However, limited information is available on the degradation behavior of plastics, especially biodegradable ones, in dune habitats. Moreover, the effects of plastics on dune plant growth and ability to withstand environmental stresses and invasion by non-native plants have been largely neglected. This is a particularly relevant issue since biological invasions are major threats to dune ecosystems. In this 18-month study, we examined the degradation behavior of two plastic bags, non-biodegradable (NBP) or biodegradable/compostable (BP), in the dune environment by visual observations and analytical techniques. Concomitantly, we investigated the individual and combined effects of bag type and sand burial (no burial vs. partial burial) on the performance of a native dune plant (Thinopyrum junceum) and an invasive plant (Carpobrotus sp.) and on their interaction. NBP did not show relevant degradation signs over the experimental period as expected. BP exhibited gradual surface modifications and changes in chemical functionality and were almost disintegrated after 18 months. Bags and burial reduced independently T. junceum survival and growth, and most plants died within 8 months of plastic exposure. Bags and burial did not affect Carpobrotus survival. However, burial decreased Carpobrotus growth while NBP increased it. Both plastics increased Carpobrotus competitive ability, and no T. junceum plants survived to co-occurrent Carpobrotus, BP, and burial. These findings indicate that removing all littered plastics from beach-dune systems not only is critical to reduce plastic pollution but also to prevent further spread of invasive species in coastal dunes.

In order to improve the lignin exploitation to added-value bioproducts, a mild chemical conversion route based on electrochemistry was investigated. For the first time, soda lignin Protobind™ 1000 (technical lignin from the pulp & paper industry) was studied by cyclic voltammetry to preliminarily investigate the effect of the main reaction parameters, such as the type of electrode material (platinum, nickel oxide hydroxide, graphite), the pH (12, 13, 14), the scan rate (10, 50, 100, 250 mV s-1), the substrate concentration (2, 20 g L-1) and the oxidation/reduction potential (from -0.8 to +0.8 V). Under the optimal reaction conditions among those tested (NiOOH electrode, pH 14, lignin 20 g L-1, 0.4 V), the electro-oxidative depolymerisation of lignin by electrolysis was performed in a divided cell. The reaction products were identified and quantified by ultra-pressure liquid chromatography coupled with mass spectrometry. The main products were sinapic acid, vanillin, vanillic acid, and acetovanillone. The obtained preliminary results demonstrated the potential feasibility of this innovative electrochemical route for lignin valorisation for the production of bio-aromatic chemicals. This journal is

Hydrothermal carbonization (HTC) is emerging as a promising technology for the management of sewage sludge. The fate of phytosanitary products, Polycyclic aromatic hydrocarbons (PAHs) and PCBs (Polychlorinated biphenyls) after HTC, as well as the formation of dioxins and furans, is still unclear. Moreover, only little information is available on the distribution of heavy metals and major nutrients between the hydrochars and the process water. Here, we aim to contribute to fill these gaps. HTC of sewage sludge from six different wastewater treatment plants has been carried out at 220 °C for 85 min. Feedstock, hydrochars and spent liquor have been then characterized and discussed. HTC is here proven to be a suitable technology for the immobilization of both heavy hydrocarbons and heavy metals, with the exception arsenic, which was also found in the spent liquor at a significant proportion (∼15-∼50%). DDD, DDT, DDE were detected in all sludge samples and their content was reduced by nearly one order of magnitude after the process. HTC is here proven to not be responsible at an appreciable extent of PCBs enrichment of the processed solids. Moreover, the sum of PCDDs and PCDFs in hydrochars never exceeded 20 ng kg

Hydrothermal carbonization offers the opportunity to reduce the issues related to the management of sewage sludge, enhancing dewaterability and avoiding thermal treatment prior landfill disposal or incineration, as water acts as a subcritical medium which catalyzes the process. The hydrochar obtained can find sustainable application as fuel, sorbent and soil amendment. Here, the effects of activation temperature (550–750 °C), time (1–4 h) and impregnation ratio potassium hydroxide: hydrochar (1–3), as well as their interactions, were investigated by Response Surface Methodology. The carbonaceous sorbent was then applied for the removal of terbuthylazine from aqueous solutions. Solid yields up to 32.31% were obtained, with corresponding ash content ranging from 13.05 to 35.06%. The combined effect of time and temperature significantly affects the ash content. An increase of impregnation ratio or temperature leads to low yields but high terbuthylazine adsorption, while the effect of the activation time on the pollutant removal is negligible. Up to 63.87% of the herbicide was adsorbed by the activated material, at terbuthylazine concentration of 2.5 mg L−1. The developed sorbent well fits the circular economy approach, offering a promising potential for sewage sludge management, as well as for water remediation.

The depletion of fossil resources is driving the research towards alternative renewable ones. Under this perspective, 5-hydroxymethylfurfural (HMF) represents a key molecule deriving from biomass characterized by remarkable potential as platform chemical. In this work, for the first time, the hydrogenation of HMF in ethanol was selectively addressed towards 2,5-bis(hydroxymethyl)furan (BHMF) or 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) by properly tuning the reaction conditions in the presence of the same commercial catalyst (Ru/C), reaching the highest yields of 80 and 93 mol%, respectively. These diols represent not only interesting monomers but strategic precursors for two scarcely investigated ethoxylated biofuels, 2,5-bis(ethoxymethyl)furan (BEMF) and 2,5-bis(ethoxymethyl)tetrahydrofuran (BEMTHF). Therefore, the etherification with ethanol of pure BHMF and BHMTHF and of crude BHMF, as obtained from hydrogenation step, substrates scarcely investigated in the literature, was performed with several commercial heterogeneous acid catalysts. Among them, the zeolite HZSM-5 (Si/Al=25) was the most promising system, achieving the highest BEMF yield of 74 mol%. In particular, for the first time, the synthesis of the fully hydrogenated diether BEMTHF was thoroughly studied, and a novel cascade process for the tailored conversion of HMF to the diethyl ethers BEMF and BEMTHF was proposed.

Commercial niobium and synthesized zirconium phosphates were tested as water-tolerant heterogeneous acid catalysts in the hydrothermal conversion of different bio-based substrates. Different acid-catalyzed reactions were performed using biomass-derived model compounds and more complex real lignocellulosic biomasses as the substrate. The conversion of glucose and cellulose was preliminarily investigated. Then, a wide plethora of raw lignocellulosic biomasses, such as conifer wood sawdust, Jerusalem artichoke, sorghum, miscanthus, foxtail millet, hemp and Arundo donax, were valorized towards the production of water-soluble saccharides, 5-hydroxymethylfurfural (HMF), levulinic acid (LA) and furfural. The different catalytic performances of the two phosphates were explained on the basis of their acid features, total acidity, Brønsted/Lewis acid sites ratio and strength. Moreover, a better insight into their structure–acidity relationship was proposed. The different acid properties of niobium and zirconium phosphates enabled us to tune the reaction towards target products, achieving from glucose maximum HMF and LA yields of 24.4 and 24.0 mol%, respectively. Remarkably, when real Jerusalem artichoke biomass was adopted in the presence of niobium and zirconium phosphate, maximum yields of furanic compounds and cellulose-derived sugars of 12.7 and 50.0 mol%, respectively, were obtained, after only 1 h of reaction. The synthesized hydrolysates, which were found to be rich in C5 and C6 carbohydrates, can be better exploited for the cascade production of more added-value bio-products.

The management of grape pomace (GP), the main winery solid residue, is presently supported by government subsidies, promoting the energetically expensive recovery of ethanol by distillation. This work proposes and assesses a novel sustainable alternative GP valorisation strategy: chain elongation fermentation. Besides, the proof-of-concept of a multipurpose cascading scheme is presented based on experimental data for each step on the laboratory scale. The new cascading biorefinery scheme includes: (1) the ethanol upgrade into highly concentrated (ca. 900 g L−1) n-hexanoic acid (C6) by anaerobic acidogenic fermentation and a simple downstream; the exploitation of the obtained C6 as (2) a reagent for obtaining an ester-alcohol mixture as well as (3) a substrate for the production of medium chain length polyhydroxylalkanoates (mcl-PHAs), and (4) the complementary biomethanization of the solids leftovers from the acidogenic step. Specifically, the identified fermentation conditions (pH 7, 37 °C and P > Patm) allowed obtaining the highest C6 titer (22 g L−1) and productivity (6.2 g L−1 d−1) ever achieved from non pre-treated biowaste and without the need of either exogenus ethanol or methanization inhibitor or expensive in-line extraction methods. Such titer, allowed employing a cheap easy-direct C6 downstream leading to 54% C6 recovery (87% purity) at potentially competitive overall costs. Although a preliminary assessment showed that this partial valorisation could be economically sustainable in itself for GP-management, the exploitation of the highly concentrated GP-derived C6 was demonstrated for the first time. Heterogenous catalytic hydrogenation (180 °C and 115 bar), with pre-reduced commercial catalyst Re/C 5 wt%, allowed the conversion of the obtained C6 into a mixture of 1-hexanol and hexyl-hexanoate (molar yield of 75%), which represents a promising blendstock for both diesel and biodiesel fuels. On the other hand, a fed-batch culture system, carried out on a bench-top bioreactor, allowed obtaining 60% PHA content with a yield of 0.30 g g−1. The recovered sticky bioelastomer was mainly composed of 3-hydroxyhexanoate (90%). Complementarily, ca. 200 N-L kgVS−1 of biomethane was obtained from GP leftover solids.

In vitro models of biological barriers provide a reliable tool for investigating the physiopathological processes involved in the development of numerous diseases. Producing sustainable in vitro models obtained from solvents and biopolymers derived from industrial by-products add an important value to this underestimated source of valuable (bio)materials. This works aims at demonstrating the suitability of processing together solvents derived from levulinic acid (LA) (extracted from biomasses) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) (whose production is facilitated by LA) to produce electrospun membranes as proof-of-concept of a sustainable, engineered biological barrier fully derived from LA as the starting feedstock. The electrospinning process is initially optimized by identifying the most suitable conditions for obtaining self-supporting microporous membranes. In particular, LA-derived solvents (γ-valerolactone, 2-methyltetrahydrofuran, methyl ethyl ketone, and methyl and ethyl levulinate), PHBV concentration, and electrospinning process parameters were investigated. Self-standing and hydrophobic PHBV mats with a micropore size in the range of 1–7 μm and an average elastic modulus of 75 MPa are successfully obtained by using methyl ethyl ketone/formic acid as solvent. Preliminary cell experiments demonstrate that the developed fibrous PHBV mats promote the formation of a confluent monolayer of epithelial cells after 48 h and therefore they can potentially be used to mimic biological epithelial barriers.

Starting from bioethanol it is possible, by using an appropriate catalyst, to produce ethyl acetate in a single reaction step and pure hydrogen as a by-product. Two molecules of hydrogen can be obtained for each molecule of ethyl acetate produced. The mentioned reaction is reversible, therefore, it is possible to hydrogenate ethyl acetate to reobtain ethanol, so closing the chemical cycle of a Liquid Organic Hydrogen Carrier (LOHC) process. In other words, bioethanol can be conveniently used as a hydrogen carrier. Many papers have been published in the literature dealing with both the ethanol dehydrogenation and the ethyl acetate hydrogenation to ethanol so demonstrating the feasibility of this process. In this review all the aspects of the entire LOHC cycle are considered and discussed. We examined in particular: the most convenient catalysts for the two main reactions, the best operative conditions, the kinetics of all the reactions involved in the process, the scaling up of both ethanol dehydrogenation and ethyl acetate hydrogenation from the laboratory to industrial plant, the techno-economic aspects of the process and the perspective for improvements. In particular, the use of bioethanol in a LOHC process has three main advantages: (1) the hydrogen carrier is a renewable resource; (2) ethanol and ethyl acetate are both green products benign for both the environment and human safety; (3) the processes of hydrogenation and dehydrogenation occur in relatively mild operative conditions of temperature and pressure and with high energetic efficiency. The main disadvantage with respect to other more conventional LOHC systems is the relatively low hydrogen storage density.

The depletion of fossil resources makes the transition towards renewable ones more urgent. For this purpose, the synthesis of strategic platform-chemicals, such as 5-hydroxymethylfurfural (HMF), represents a fundamental challenge for the development of a feasible bio-refinery. HMF perfectly deals with this necessity, because it can be obtained from the hexose fraction of biomass. Thanks to its high reactivity, it can be exploited for the synthesis of renewable monomers, solvents, and bio-fuels. Sustainable HMF synthesis requires the use of waste biomasses, rather than model compounds such as monosaccharides or polysaccharides, making its production more economically advantageous from an industrial perspective. However, the production of HMF from real feedstocks generally suffers from scarce selectivity, due to their complex chemical composition and HMF instability. On this basis, different strategies have been adopted to maximize the HMF yield. Under this perspective, the properties of the catalytic system, as well as the choice of a suitable solvent and the addition of an eventual pretreatment of the biomass, represent key aspects of the optimization of HMF synthesis. On this basis, the present review summarizes and critically discusses the most recent and attractive strategies for HMF production from real feedstocks, focusing on the smartest catalytic systems and the overall sustainability of the adopted reaction conditions.

A large fraction of plastic litter found in natural environments is constituted by conventional not biodegradable plastic bags, and their adverse effects via ingestion or entanglement on terrestrial and marine organisms are largely documented. Biodegradable and compostable shoppers have been recently developed as alternative to traditional ones. These bags are specifically designed to degrade in composting facilities and generate a product devoid of toxicity to soils and crops. However, very little is known on the effects of bag leaching, i.e. the transfer of chemicals from plastic into natural environments, on vegetation. Some plant species are highly sensitive to a variety of chemicals, and seedling growth is generally the most affected life history stage. In this study we assessed the potential effects of conventional (high-density polyethylene, HDPE) and compostable (Mater-bi®, MB) bags, when left in natural environments, on water quality and plant development. To this end, seeds of Lepidium sativum L., a terrestrial plant commonly used in phytotoxicity standard tests, were exposed to leachates obtained from different amount of HDPE and MB bags, simulating various pollution degrees occurring in nature, for 72 h. Both not-exposed (or virgin) bags and natural weathering exposed bags were used. Variations of chemical-physical characteristics of extracts were used as indicative of water quality deterioration, while alterations of seed gemination and seedling radicle and hypocotyl length were considered as indicative of phytotoxicity. A chemical qualitative screening of the leachates was also performed to identify the compounds with potential phytotoxicity. Both types of bags affected water characteristics (pH, salinity and total dissolved solids) relevant to plants, and released into water intentionally added chemicals, such as the noxious bisphenol A, and other phytotoxic substances probably generated during bag manufacturing. Leachates from both bag types did not affect seed germination. But, a significant number of seedlings showed developmental abnormalities or reduced seedling growth. The hypocotyl was the most sensible seedling organ to HDPE bag leachates while the radicle was the most vulnerable to MB ones. These findings indicate that plastic bags, including those that meet biodegradability and compostability standards, represent a potential threat to plants, if left in natural environments. Therefore, people and managers should be adequately informed about the potential environmental impact of an incorrect bag disposal. Simple, rapid standard phytotoxicity tests, such as the L. sativum bioassay, applied to bag leachates could be used in the future to select not noxious additives so to develop more eco-friendly bags.

Hydrothermal carbonization (HTC) of sewage sludge reduces the waste volume and can be source of energy and valuable products. Furthermore, HTC offers several advantages over conventional dry-thermal pre-treatments, as no prior drying is requested, and the high quality of the char produced promotes applications as energy production and storage, wastewater remediation, and soil amendment. Relationships between char yields, physicochemical properties and process parameters are here analysed, with the aim to provide insight into the choice of the process severity required to fit the desired application. Moreover, presence and fate of heavy metals and organic contaminants are discussed. The highest reaction temperature is the main parameter affecting the physicochemical characteristics of the char produced, while the heating rate governs the heat mass transfer and the rate of intermediates formation. Depolymerization of the biomass results in a reduction of the oxygen to carbon ratio and, therefore, in augmented high heating values, further increased by deposition of 5-(hydroxymethyl)furfural. Recirculation of process water may enhance dehydration reactions and the deposition of degraded polymers, increasing dewaterability and yield, but field trials are recommended to assess the feasibility of this option. An overuse of chars for energy generation purposes would be deleterious for the environmental life cycle. Further research is encouraged to assess the pollutants abatement and their degradation pathways when incorporated in the carbonaceous product, to promote the application of hydrochars as soil amendment, as well as for environmental remediation purposes.

5-Hydroxymethyl-2-furaldehyde (HMF) is one of the top 12 biobased chemicals, precursor of renewable monomers and biofuels. This key molecule can be obtained from the dehydration of monosaccharides ...

This study reports the sustainable production of butyl levulinate (BL) from furfuryl alcohol (FA), a highly abundant biomass derived platform obtained from C5 sugars in hemicellulose. FA upgrading is performed adopting a robust and easily recyclable commercial perfluorosulfonic acid resin, Aquivion® P87S, used as cylinder shaped pellets. This approach avoids the use of corrosive and harmful mineral acids allowing a simple separation of the catalyst from the reaction mixture, reducing the cost of equipment materials and disposal or neutralization issues, also resulting in reduced solvent dehydration. Moreover, FA alcoholysis to BL involves butanol as a sustainable reaction medium, also readily obtained from biomass. The catalyst remains stable up to 6 recycles. Furthermore, the absence of heavy by-products and the stability of the catalyst allowed us to perform successive additions of the substrate to the reaction medium to increase the BL concentrations up to 0.66 M (13 wt%).

In recent years, biofuels have been attracting more attention, especially in Europe, due to the new regulations concerning the improvement of renewables in fuel composition. The acid-catalysed alcoholysis reaction of the cellulosic fraction of raw and pre-treated lignocellulosic biomasses, using n-Butanol (n-BuOH) and diluted inorganic acid as homogeneous catalyst, produces a mixture mainly composed by Butyl Levulinate (BL) from cellulose, Dibutyl ether (DBE) from n-BuOH etherification and unreacted n-BuOH. This last can be then separated and recycled, so increasing the sustainability of the whole process. BL is directly obtained from cellulosic fraction of not edible biomass and represents a promising advanced biofuel. Therefore, in the different types of blends containing the main products obtainable from the one-pot alcoholysis of lignocellulosic biomasses, BL represents the effective renewable component of the fuel. In this work, different blends of BL/DBE mixed with Diesel fuel were tested in a small single-cylinder air-cooled Diesel engine with direct injection. Data concerning the measurement of pollutant emission, engine performance and combustion characteristics are reported. Results have been compared with those obtained fuelling the engine with a conventional Diesel fuel. The mixtures were prepared by using commercial reactants, characterized by compositions analogous to those of the reaction mixtures. The obtained results evidenced the potentiality of these novel blending mixtures to reduce the emissions of particulate without any increasing of NOx emission or changing in engine power and efficiency.

Cutaneotrichosporon oleaginosus is an oleaginous yeast with several favourable qualities: It is fast growing, accumulates high amounts of lipids and has a very broad substrate spectrum. Its resistance to hydrolysis by-products makes it a promising biocatalyst for custom tailored microbial oils. C. oleaginosus can accumulate up to 60 wt.% of its biomass as lipids. This species is able to grow by using several compounds as a substrate, such as acetic acid, biodiesel-derived glycerol, N-acetylglucosamine, lignocellulosic hydrolysates, wastepaper and other agro-industrial wastes. This review is focused on state-of-the-art innovative and sustainable biorefinery schemes involving this promising yeast and second- and third-generation biomasses. Moreover, this review offers a comprehensive and updated summary of process strategies, biomass pretreatments and fermentation conditions for enhancing lipid production by C. oleaginosus as a whole-cell biocatalyst. Finally, an overview of the main industrial applications of single-cell oil is reported together with future perspectives.

Coffee is one of the largest consumed drinks all over the world, generating a very significant amount of wastes during the beans processing. Among these by-products, coffee silverskin is a very interesting waste material, being a promising source of bioactive compounds, including valuable polyphenols as chlorogenic acids and caffeine. In order to valorize these valuable components, they should be isolated from the starting matrix through suitable processes, but the current conventional extraction procedures are not suitable. On the contrary, microwave-assisted extraction results particularly efficient, nowadays finding many applications in various fields. On this basis, the aim of the present research is the investigation and the optimization of the solid-liquid extraction of valuable antioxidant polyphenols from coffee silverskin under microwave irradiation. The influence of the main reaction parameters, such as temperature, extraction time and composition of the solvent, consisting of a green binary mixture of water/ethanol, has been assessed, also employing statistical modeling. Maximum yield in total polyphenols of about 45 mgGAE/g, expressed as mg of gallic acid equivalent for g of starting biomass, was experimentally achieved, a promising value, thus leading to an important step forward, in the perspective of improving this waste recycling in a circular economy perspective., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 699-707

Single cell oil (SCO) represents an outstanding alternative to both fossil sources and vegetable oils from food crops waste. In this work, an innovative two-step process for the conversion of cellulosic paper mill waste into SCO was proposed and optimised. Hydrolysates containing glucose and xylose were produced by enzymatic hydrolysis of the untreated waste. Under the optimised reaction conditions (Cellic® CTec2 25 FPU/g glucan, 48 h, biomass loading 20 g/L), glucose and xylose yields of 95 mol% were reached. The undetoxified hydrolysate was adopted as substrate for a batch-mode fermentation by the oleaginous yeast Lipomyces starkeyi. Lipid yield, content for single cell, production and maximum oil productivity were 20.2 wt%, 37 wt%, 3.7 g/L and 2.0 g/L/d respectively. This new generation oil, obtained from a negative value industrial waste, represents a promising platform chemical for the production of biodiesel, biosurfactants, animal feed and biobased plastics.

Following the “Letter to the Editor regarding the article “Evaluation of the phytotoxicity of conventional and biodegradable plastic bags using seed germination tests” by Balestri et al. (2019) published on Ecological Indicators 102(2019):569–580” by Degli-Innocenti et al. (2019), we replied to the concerns expressed by Degli Innocenti and co-authors in this letter regarding our article.

The present investigation represents a concrete example of complete valorization of Eucalyptus nitens biomass, in the framework of the circular economy. Autohydrolyzed-delignified Eucalyptus nitens was employed as a cheap cellulose-rich feedstock in the direct alcoholysis to n-butyl levulinate, adopting n-butanol as green reagent/reaction medium, very dilute sulfuric acid as a homogeneous catalyst, and different heating systems. The effect of the main reaction parameters to give n-butyl levulinate was investigated to check the feasibility of this reaction and identify the coarse ranges of the main operating variables of greater relevance. High n-butyl levulinate molar yields (35&ndash, 40 mol%) were achieved under microwave and traditional heating, even using a very high biomass loading (20 wt%), an eligible aspect from the perspective of the high gravity approach. The possibility of reprocessing the reaction mixture deriving from the optimized experiment by the addition of fresh biomass was evaluated, achieving the maximum n-butyl levulinate concentration of about 85 g/L after only one microwave reprocessing of the mother liquor, the highest value hitherto reported starting from real biomass. The alcoholysis reaction was further optimized by Response Surface Methodology, setting a Face-Centered Central Composite Design, which was experimentally validated at the optimal operating conditions for the n-butyl levulinate production. Finally, a preliminary study of diesel engine performances and emissions for a model mixture with analogous composition to that produced from the butanolysis reaction was performed, confirming its potential application as an additive for diesel fuel, without separation of each component.

In the recent years the progressive decrease in fossil petroleum resources and gradual deprivation of the environment have attracted increasing interest towards the use of biomass as renewable carbon source for the production of chemicals and transportation fuels. In particular, lignocellulosic biomass represents an abundant and inexpensive renewable resource with high carbon sequestration ability and non-polluting. In this paper, the valorisation of mixtures made of n-butanol (n-BuOH), butyl levulinate (BL) and dibutyl ether (DBE), in different percentages, as additive fuel for compression ignition (CI) internal combustion engine (ICE) was studied. These mixtures can be directly obtained from the catalytic alcoholysis reaction of the cellulosic fraction of raw and pre-treated lignocellulosic biomasses. Moreover, the possibility to recycle and reutilize the excess alcohol (n-Butanol), during the catalytic alcoholysis reaction, has been considered since it represents an opportunity to reduce the overall costs of the process. Therefore, a blend constituted only by BL and DBE has been also tested. The model mixtures were prepared by using commercial reactants, characterized by compositions analogous to those of the reaction mixtures. These model mixtures were tested as blend with Diesel fuel in a CI-ICE with the measurement of pollutant emission and performance. Results have been compared with those obtained fuelling the engine with a commercial Diesel fuel. As a whole, tests results have evidenced the potentiality of these novel blending mixtures to reduce the emissions of particulate without any significant increase in the other pollutants and negligible changes in engine power and efficiency.

Furfural was produced in biphasic media using a microwave-heated reactor. Diverse substrates were considered: xylose (considered as a reference compound) or hemicellulosic saccharides from Eucalypt...

Up to now, on the industrial scale, the acid-catalysed hydrothermal conversion of lignocellulosic biomass has been targeted to the production of levulinic acid (LA), while the lignin fate has been neglected, and its use has been limited at most to the energy recovery. Now, an integrated investigation of the hydrothermal process for the synthesis of LA starting from giant reed (Arundo Donax L.) was studied taking into account the lignin phenol derivatives present in the liquid phase and in the solid hydrochar. The analysis of the hydrochar was carried out adopting coupled pyrolysis techniques, e.g. Py-GC/MS, TGA/FTIR, and EGA-MS, paying a special attention to the contribution of the evolved simple phenolics. The hydrochar washing fractions were analyzed for the total phenolic content (TPC) and antioxidant activity (AA), adopting TEAC, FRAP, and DPPH standard essays, comparing the antioxidant activities with those deriving from the starting LA-rich mother liquor. Two washing cycles allowed the complete recovery of the phenolic compounds of interest, leached from the porous hydrochar. Also the starting LA-rich liquor was of great interest for the same purpose, having the highest content of these compounds, which must be necessarily removed for the production of the commercial pure LA. Promising antioxidant properties were ascertained for the mother liquor and the hydrochar washings, obtaining good linear correlations between total phenolic compounds (TPC) and antioxidant capacity (TEAC, FRAP, and DPPH). This multi-valorisation approach contributes to improving the sustainability of the entire LA process and shifts the attention towards the antioxidants, new niche bioproducts of great interest, which add significant economic value to the overall Biorefinery of the lignocellulosic biomass.

The ruthenium compounds [(η6-p-cymene)RuCl{κ2N-(HCNR)2}]NO3 (R = 4-C6H4Me, [1]NO3; 4-C6H4OH, [2]NO3; C6H11Cy, [3]NO3; 4-C6H10OH, [4]NO3; tBu, [5]NO3) were prepared in high yields from [(p-cymene)RuCl2]2, AgNO3 and the appropriate α-diimine. Compounds [2]PF6 and [4]PF6 were obtained by a straightforward reaction of [(η6-p-cymene)RuCl(MeCN)0.66]PF6, [6]PF6, with α-diimine, whereas [4]BPh4 was obtained by metathesis between [4]NO3 and NaBPh4. All the ruthenium products were characterized by analytical methods, IR, NMR and UV-Vis spectroscopy; in addition, the structure of [1]NO3 was ascertained by an X-ray diffraction study. Compounds [1–4]NO3, [4]PF6 and [4]BPh4 were investigated as catalytic precursors in the transfer hydrogenation reaction of ethyl levulinate to γ-valerolactone in isopropanol solution under microwave irradiation. [4]BPh4 was revealed to be the best catalytic precursor, affording γ-valerolactone in 62% yield under optimized experimental conditions.

Hydrolysis and butanolysis of lignocellulosic biomass are efficient routes to produce two valuable bio-based platform chemicals, levulinic acid and n-butyl levulinate, which find increasing applications in the field of biofuels and for the synthesis of intermediates for chemical and pharmaceutical industries, food additives, surfactants, solvents and polymers. In this research, the acid-catalyzed hydrolysis of the waste residue of Cynara cardunculus L. (cardoon), remaining after seed removal for oil exploitation, was investigated. The cardoon residue was employed as-received and after a steam-explosion treatment which causes an enrichment in cellulose. The effects of the main reaction parameters, such as catalyst type and loading, reaction time, temperature and heating methodology, on the hydrolysis process were assessed. Levulinic acid molar yields up to about 50 mol % with levulinic acid concentrations of 62.1 g/L were reached. Moreover, the one-pot butanolysis of the steam-exploded cardoon with the bio-alcohol n-butanol was investigated, demonstrating the direct production of n-butyl levulinate with good yield, up to 42.5 mol %. These results demonstrate that such residual biomass represent a promising feedstock for the sustainable production of levulinic acid and n-butyl levulinate, opening the way to the complete exploitation of this crop.

5-hydroxymethylfurfural (HMF), accessible from various feedstocks, represents an important renewable platform-chemical, precursor for valuable biofuels and bio-based chemicals. In this work, the continuous hydrogenation of an aqueous solution of HMF to give strategic monomers, 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) was investigated in a continuous flow reactor adopting a commercial Ru/C (5 wt%) as catalyst. The influence of the main process variables on products yield and selectivity was studied and optimized. The highest BHMF and BHMTHF yields of 87.9 and 93.7 mol%, respectively, were achieved by tuning the catalyst contact time, keeping all other variables constant (temperature, pressure, hydrogen flow rate, initial HMF concentration). Intraparticle diffusion limitation for hydrogen and HMF was shown to occur at some of the tested conditions by performing the HMF hydrogenation with different catalyst particle sizes, confirmed by calculations. Constant catalyst activity was observed up to 6 h time-on-stream and then gradually reduced. Fresh and spent catalyst characterization showed no significant sintering and negligible leaching of ruthenium during time-on-stream. A decrease of the specific surface area was observed, mainly due to humin deposition which is likely the reason for catalyst deactivation. Catalyst performance could be restored to initial values by a thorough washing of the catalyst.

International audience; We successfully prepared copper-based magnetic catalysts combining copper oxide and magnetite nanoparticles. These systems are active and selective in the oxidative homocoupling reaction of phenylacetylene in the absence of an external base. These systems are particularly interesting since the addition of an external base induces copper leaching by production of soluble molecular copper-base complexes. Some of these systems were also supported on oxidized few layer graphene to investigate a potential role of this support. We discover that this supported system is three times more active than the other ones. We propose that the role of graphene support is to improve catalyst dispersion, but also to provide a favorable micro-environment around the active phase via a pre-adsorption of the substrate on the support, which affords a substrate rich micro-environment around the active particles. Recycling experiments show that the graphene-supported systems cannot be recycled, while the other ones can. This result could be explained by a competitive pre-adsorption between the substrate and the product of the reaction on the surface of the support.

Since safety hazards can occur during the life of a Li-ion battery, understanding its behaviour under abusive conditions is important for the development of a safe cell. In this work, overcharge tests on commercial Li-polymer cells were conducted, resulting in gas evolution. A comprehensive postmortem analysis of the abused cells was planned to be carried out by means of several analytical techniques: gas phase chromatography for the identification of the exhaust gases, scanning electron microscopy and energy X-ray spectrometry for the investigation of the cathode and anode materials, Fourier-transform infrared spectroscopy for the study of the electrolyte composition, etc.). First interesting results, regarding the characterization of a high temperature overcharged cell and the detection of flammable and toxic species produced by the cell, are presented in this paper.