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This paper is focused on the utilization of hybrid catalysts obtained from layered double hydroxides containing molybdate as the compensation anion (Mo-LDH) and graphene oxide (GO) in advanced oxidation using environmentally friendly H2O2 as the oxidation agent for the removal of indigo carmine dye (IC) from wastewaters at 25 °C using 1 wt.% catalyst in the reaction mixture. Five samples of Mo-LDH-GO composites containing 5, 10, 15, 20, and 25 wt% GO labeled as HTMo-xGO (where HT is the abbreviation used for Mg/Al in the brucite type layer of the LDH and x stands for the concentration of GO) have been synthesized by coprecipitation at pH 10 and characterized by XRD, SEM, Raman, and ATR-FTIR spectroscopy, determination of the acid and base sites, and textural analysis by nitrogen adsorption/desorption. The XRD analysis confirmed the layered structure of the HTMo-xGO composites and GO incorporation in all samples has been proved by Raman spectroscopy. The most efficient catalyst was found to be the catalyst that contained 20%wt. GO, which allowed the removal of IC to reach 96.6%. The results of the catalytic tests indicated a strong correlation between catalytic activity and textural properties as well as the basicity of the catalysts.

Current industrial methods of biodiesel production lead to an excess of crude glycerin which requires costly purification before commercialization. Production of oxygenated fuel additives is a potential route for glycerin valorization. Glycerin acetylation was carried out over heterogeneous acid catalysts (15%, glycerol weight basis) using glacial acetic acid (molar ratio = 9). The catalysts, containing different amounts of phosphate species (P/Si from 10 to 20 atomic ratio), were prepared by wet impregnation of commercial silica with aqueous solutions of diammonium phosphate and ortho-phosphoric acid. X-ray diffraction patterns of calcined solids presented amorphous patterns like raw silica. The prepared catalysts presented, at 120 °C, glycerol conversion higher than 89.5% after 1 h of reaction, been diacetin the major product, with triacetin selectivities lower than 26.1%. Diacetin selectivity was found to be almost invariant with catalyst acidity thus underlining the relevance of catalyst porosity due to the large acetins molecules sizes. The slow rate of triacetin diffusion in narrow pores of catalyst might be responsible for the relatively low yield obtained. Surface phosphate species showed a slow rate of leaching in the reaction medium showing high catalyst stability.

Ethanolysis of soybean oil was carried out over lime catalyst produced by calcination of scallop shells food wastes. The as prepared catalyst showed XRD lines belonging to lime, whereas post reaction samples presented XRD pattern belonging to Ca(OH)2 overlaid with lines of calcium diglyceroxide. The catalyst dynamics during ethanolysis was similar to that reported for methanolysis, being hydration and consequent diglyceroxide formation the main transformations of CaO catalyst during reaction. The influence of the reaction parameters, such as ethanol:oil molar ratio (10:1–14:1), catalyst loading (10–15%, based in oil weight) and time reaction (6–10 h), on the FAAE (fatty acids ethyl esters) yield was analyzed by response surface methodology. A polynomial model was fitted using Minitab software, showing a correlation between predicted and experimental FAEE yields of 0.921. The maximum FAEE yield of 99.2% was computed for optimal reaction parameters of 11:1 ethanol:oil molar ratio; 13.8% catalyst loading and 9.1 h of reaction time. The fitted model was verified for the optimal conditions, using three replicas, given 99.0% of FAEE yield instead of the 99.2% predicted.

Biodiesel can substitute for conventional diesel fuel and contribute to the decarbonization of the transportation sector. To improve biodiesel sustainability and decrease production costs, low-grade fats such as non-edible animal fats must be used. Animal fats are mixed with tissues which must be removed before alcoholysis to avoid biodiesel contamination with nitrogen and phosphorus-containing compounds. Biodiesel was produced by the methanolysis of beef tallow and beef tallow/soybean oil mixtures over calcium heterogeneous catalysts obtained by the calcination of scallop shells. The tallow from fatty bovine tissues was extracted using boiling water, dry microwave treatment, and acetone extraction. The thermal stability and the moisture content of the extracted fats were evaluated by thermogravimetry. The thermograms of fats revealed that microwave treatment, which was faster (3 min instead of 40 min for boiling water and 240 min for acetone extraction) and had the lowest energy consumption, led to a dry fat with a thermal stability analogous to that of fats extracted with boiling water and acetone. All the extracted fats behaved similarly in the methanolysis reaction over calcium catalyst, with biodiesel yield (61–62%) being 30% lower than the analogous obtained from soybean oil (88%). Co-processing the extracted tallow with soybean oil overcomes the drawback related to the low-grade fats.

Poplar biomass of nine different genotypes, from short rotation coppice, was pyrolyzed in a fixed bed reactor using several solid catalysts. Pine bark was used as reference for uncatalyzed pyrolysis. Pyrolysis tests were performed for temperatures in the range 425–500 °C, selected from the thermal degradation profiles obtained by thermogravimetry under N2 flow. All the analyzed poplar genotypes showed similar pyrolysis behavior, with the highest bio-oil yield (53% average value) being obtained for the highest tested temperature (500 °C). In analogous conditions, the pine bark resulted in higher bio-char yields than poplar biomass, due to its larger lignin content. Catalyzed pyrolysis carried out at 500 °C using 10% of catalyst (Wcat/Wbiomass) for H-ZSM5 and FCC (spent catalyst from Fluid Catalytic Cracking unit) zeolites, and Mg and Na carbonates, showed improved gasification with slightly lower liquid production. The FCC catalyst promoted the lowest depreciation of bio-oil yield with the highest decrease of acid functional groups. All the used catalysts were effective to lessen the acidic components of the produced bio-oils thus having a beneficial effect on the pyrolysis liquid products.

The evaluation of the amount of lignocellulosic polymeric components of woody biomass is fundamental to assess its adequacy to produce energy or chemicals. Classic techniques for quantification of these components are slow and laborious, and modern expeditious techniques such as thermogravimetry (TG) have allowed for new and accurate measurement methodologies. TG was used to analyze woody biomass and lignocellulosic composition was assessed through deconvolution of rate of mass loss curves with a pseudo-component model. The quantification of hemicelluloses, cellulose and lignin was performed for nine different poplar genotypes grown as a short rotation coppice (SRC) in Portugal and Belgium. The average composition was (% mass, dry basis) 23% hemicelluloses, 49% cellulose and 27% lignin, with the remaining 1% ash. The classic determination of lignin (Klason) allowed to comparable content (29%). Moreover, TG results agree with published data obtained by conventional wet techniques for poplar wood. The usefulness of the application of TG for lignocellulosic content determination was verified, allowing useful and simple characterization of biomass for thermochemical conversion processes. SRCs are envisaged as an auspicious renewable source of woody biomass, and TG can be a valuable tool to improve the knowledge of factors related to the influence of genetic and environmental conditions on biomass quality.

Lime based catalysts are reported to be active in oil alcoholysis, biodiesel production, but their sensitivity to moisture and atmospheric CO2 can hinder their use at the industrial level because it is suspected that they must be manipulated in a controlled atmosphere. The storage stability of lime catalyst was investigated for 180 days (temperature in the range 20–38 °C, relative humidity higher than 40%). Catalytic data showed biodiesel yields ranging from 87.5%, for the first day, to 79.4% for the 180th day, passing through a maximum of 91.5% obtained in the 30th day of storage. Hydration was mainly a surface process since the Ca(OH)2 bulk phase was detected only at the end of the storage period. A catalyst stored for 10 mounts was successfully reactivated by annealing at 470 °C thus proving that CaO material is stable enough during storage and handling to be used as a biodiesel catalyst.

Original Paper Background. Strawberry by-products were explored as sources of anthocyanins for the extraction of natural colorants in the development of new value-added products for the food industry. For this purpose, the stability of strawberry anthocyanin extracts was evaluated for color and total anthocyanin content. The anthocyanins were encapsulated with inulin to protect them from processing at high temperatures and exposure to light. Microcapsules were obtained by two drying processes (spray and freeze drying) in order to study their use as coloring ingredients for their use in the food industry. Materials and methods. Thermal (using the response surface methodology – RSM) and light stability tests were performed, simulating long-term processing and food storage. Antioxidant activity, total anthocyanin content and color analysis were quantified using several methods, and the microcapsules were characterized using scanning electron microscopy. Anthocyanins and their derivatives were identified by high resolution mass spectrometry. Results. The strawberry extracts showed high antioxidant capacity and total anthocyanin content. The RSM of the thermal stability test showed that temperature is the variable with the most significant effect on color stability and total anthocyanin content. The anthocyanins showed more stability at 50°C/60 min, 57°C/102 min, 93°C/18 min and with up to 8 days of light. Microencapsulation of the strawberry extracts with inulin obtained by spray and freeze drying improved the stability of anthocyanins. The spray drying process can offer better applications for the food industry due to the more regular shape of the microcapsules, which supports the potential use of strawberry by-products as coloring ingredients for application in the food industry. Conclusion. This study can serve as a technical reference for the development of anthocyanin microcapsules with inulin from strawberry by-products obtained by spray drying, resulting in stable natural colorants to be used as ingredients in the food industry info:eu-repo/semantics/publishedVersion

Eleven ruthenium-nucleoside conjugates with the general formula [(η5-C5H5)Ru(PP)L][PF6] (PP = 1,2-bis(diphenylphosphino)ethane (Dppe), 2PPh3, and L = 3-N-(p-cyanobenzyl)thymidine derivative ligand) are reported. Both [(η5-C5H5)Ru(Dppe)NC-R]+ and [(η5-C5H5)Ru(PPh3)2NC-R]+ scaffolds exhibit remarkable stability towards hydrolysis. Compounds show high cytotoxicity in HCT116 colon cancer cells, with IC50 values down to 1.0 μM. Uptake competition experiments with 2′-deoxyadenosine revealed its cellular absorption to be independent of nucleoside transporters.

Harvesting of forest residual biomass contributes to regulating wildfires during hot and dry seasons. The collected biomass can be converted into liquid biofuel by pyrolysis. Simple pyrolysis procedures such as slow pyrolysis will allow to dimension and design of mobile pyrolysis units to avoid biomass transportation fees and guarantee efficient management of forest residues. Portuguese forest wastes, particularly biomass from maritime pinus and eucalyptus globulus, were characterized by thermogravimetry and pyrolyzed in a fixed bed reactor, at 698 K, using commercial alkali carbonates and zeolites, bauxite ores, and marble dust as catalysts. Pyrolysis data for mixed biomasses showed the existence of synergy effects. The catalytic pyrolysis experiments led to improved bio-oil quality for all the tested catalysts. The bio-oil produced from pyrolysis with sodium carbonate was the most volatile, since the maximum peak of the volatilization rate is at 390 K, while the bio-oils produced by the remaining catalysts have maximum volatilization at 410 K. Marble dust, a waste from ornamental stones industry, revealed excellent catalytic properties during biomass pyrolysis, allowing an improved bio-oil yield with a decrease in the oxygen-containing functional groups.

Hybrid graphene-based nanostructures are considered promising materials for energy storage applications. However, the synthesis of high-quality hybrid graphene nanostructures at high yields is challenging. In the present work we propose a novel, single-step microwave plasma-enabled approach to synthetize customizable hybrid graphene-based nanostructures at high-yield while preserving their quality. Hybrid N-graphene (nitrogen-doped graphene) metal-based nanostructures, for instance, can be produced at a rate of ∼ 19 mg/min. The high energy density region of a microwave plasma provides sufficient energy and “building particles” fluxes towards the low-energy density plasma afterglow for the processes of assembly and growth of N-graphene sheets. Simultaneously, a controlled jet of metal-oxide(-sulfide) microparticles is sprayed into the plasma afterglow region where they bind to N-graphene sheets. Methane/methylamine are used as carbon and nitrogen precursors, combined with micron-sized MnO2 and oxy-MnS particles to synthesize the hybrid structures. As a result, nano-sized (∼10–30 nm) MnOx particles decorated N-graphene (4.6 at. N%) and oxidized metal sulfide anchored N-graphene sheets (3.1 at. N%) are produced at atmospheric conditions. High structural quality and distribution of metal-based nanostructures on N-graphene sheets are revealed using transmission and scanning electron microscopes and other advanced spectroscopic techniques. Finally, an electrode for supercapacitor based on the N-graphene-metal-oxide(sulfide) hybrid nanostructures is developed with promising specific capacitances (∼273 F.g−1 at 0.5 A.g−1). The described chemically engineered process is one of the fastest approaches reported for designing the high-quality hybrid nanostructures produced at a high-yield, and as such, is expected to provide a high impact on the design of electrode materials for sustainable energy storage systems.

This paper investigates the reinforcement efficiency of mortars produced with different types of carbon nanotubes (CNTs) in terms of their mechanical strength, ultrasonic pulse velocity, elastic modulus, fracture toughness, shrinkage and microstructure. The incorporation of 0.05–0.1% of CNTs was able to reduce the early shrinkage up to 62% and increase the flexural strength and fracture energy up to 33% and 65%, respectively. Well-dispersed CNTs could improve the post-cracking resistance of mortars, being able to effectively bridge microcracks up to around 1 μm wide. Microscopic analysis shows that CNTs can potentially improve the quality of the cement matrix in the aggregate-paste interfacial transition zone.

The pyrolysis of food waste has a double environmental advantage as it contributes to the management and treatment of waste and allows the production of renewable fuels. Spent coffee and tea grounds, were characterized by thermogravimetry to determine their composition and evaluating the pyrolysis kinetics of each lignocellulosic pseudocomponent and pyrolyzed in a fixed bed reactor. Tea grounds had about twice the cellulose and higher pyrolysis activation energy than the coffee grounds sample. At 673 K the pyrolysis of the coffee grounds led to a 42% bio-oil yield while the tea grounds produced only 18% of liquid product, which is compatible with its higher cellulose content and the higher activation energy for pyrolysis. The alkaline carbonates used as pyrolysis catalysts led to an increase in the production of a gaseous product, bio-gas, with a reduction in the production of bio-oil but accompanied by a significant increase in the volatile fraction of the produced bio-oils. Pyrolysis data shows that both coffee and tea residues can be used as raw materials to produce pyrolysis bio-oil and that low-value materials such as alkaline carbonates can be used as pyrolysis catalysts improving the characteristics of bio-oils produced such as acidity and volatility.

Microalgae can be used for wastewater bioremediation with simultaneous CO 2 biofixation producing valuable biomass. Wastewater from a brewery was treated using the Scenedesmus obliquus microalga in bubble-column photobioreactors (PBRs). The PBRs were fed with ambient air and the effect of a 10% (v/v) brewery CO 2 supplement was studied. The PBRs were inoculated and a range of mean hydraulic residence time (HRT) values were tested (2.1–10.4 days). The maximum ash-free dry weight (AFDW) biomass productivity was obtained for a HRT of 3.5 days (0.29 d −1 dilution rate; 0.2 g L −1 d −1 (in terms of AFDW). The highest pollutant removal efficiencies were 92.9 and 88.5% for ammonia and total nitrogen, respectively, 40.8% for phosphorus, and 61.9% for COD. Except a dilution rate of 0.48 d −1 trial, the treated wastewater always met the Portuguese legislation quality standard for discharge into natural water bodies. Aiming to simultaneously maximize biomass volumetric productivity, CO 2 biofixation rate and wastewater treatment efficiency, while minimizing residence time, 0.29 d −1 represents the optimal dilution rate value. The potential of the produced Scenedesmus obliquus biomass was evaluated for the generation of biohydrogen through dark fermentation with Enterobacter aerogenes , and of bio-oil, bio-char and bio-gas through a pyrolysis process. The yields obtained were 67.1 mL H 2 g −1 (in terms of volatile solids - VS) for bioH 2 and 64, 30 and 6% for bio-oil, bio-char and bio-gas, respectively (dry mass content (%) calculated over freeze dryer biomass basis).

Mechanical activation in order to improve lithium recovery from a lepidolite ore concentrate was investigated. The concentrate was mechanically activated using different milling times and the effect on the resulting products was evaluated by X-ray powder diffraction, FTIR spectroscopy, TG-DTG analysis, SEM and particle size analysis by laser diffraction. The mechanical activation leads to lepidolite amorphization and concomitant improvement of the reactivity by sulfuric acid digestion and water leaching. About 85% of Li recovery was achieved when the concentrate was activated for 15 min and afterwards digested at 165 °C, during 4 h, using an acid/concentrate ratio of 650 g/kg. Li recoveries above 70% were reached even using digestion temperatures lower than 100 °C. However, to increase recovery, temperatures over 140 °C are more suitable. Results obtained showed that is possible to apply a low temperature technology for recovering Li from hard rock minerals, using mechanical activation.

The potential of Scenedesmus obliquus biomass, after treating several wastewaters (WWs) (urban, dairy and brewery industries, cattle and poultry breeding), was evaluated for the production of bio-char, bio-oil and bio-gas, through a pyrolysis process. The experiments were carried out in a fixed bed reactor at a temperature of 748 K during 15 min. The thermochemical behaviour of each microalga was assessed by thermogravimetry analysis and infrared spectroscopy. The bio-oils obtained were also quantified and characterized. The results reveal that (i) all microalgae show a similar thermal degradation behaviour; (ii) microalga grown in urban WW shows a lower percentage of lipids; in dairy and cattle WWs, it shows a high percentage of both proteins and lipids, and in poultry and brewery WWs, it shows a higher carbohydrates content; (iii) the microalga grown in poultry WW shows the lowest protein content, whereas the urban grown microalga showed the highest protein content; (iv) the bio-oil obtained by pyrolysis process showed yields in the range 30-60% (w/w) and showed a high content of aromatic compounds. info:eu-repo/semantics/publishedVersion

Due to sustainability issues, biodiesel must be produced from low-grade fats and the conventional homogeneously-catalyzed processes must be replaced by more efficient and more profitable production processes such as heterogeneous ones. Biodiesel (fatty acids methyl esters, FAME) was produced from a mixture (50 wt%) of soybean oil and non-edible beef tallow over heterogeneous calcium-based catalysts obtained by calcination of scallop shells. In order to improve the catalytic performances, solvent assisted methanolysis was conducted using alcohols (ethanol, 1-propanol, isopropanol and isobutanol), acetone, methylcyclohexane, and tetrahydrofuran (THF) with Vmethanol/Vsolvent = 2.8. Catalytic data revealed that alcohol solvents adsorb competitively with methanol on the catalyst active sites reducing the FAME yield due to their slower alcoholysis rates. Hexane and methylcyclohexane are inadequate for methanolysis reactions since they are immiscible with methanol. THF and acetone are immiscible with the co-produced glycerin, which favors methyl esters formation by displacing the chemical equilibrium towards reaction products. Acetone performs better than THF (FAME yield gain of 14% against 3%) because of its higher miscibility with methanol. THF was the most effective solvent to avoid fat adsorption on the catalyst surface, a key factor for catalyst stability, and to improve the glycerin purity.

Energy security and environmental concerns, related to the increasing carbon emissions, have prompted in the last years the search for renewable and sustainable fuels. Biodiesel, a mixture of fatty acids alkyl esters shows properties, which make it a feasible substitute for fossil diesel. Biodiesel can be produced using different processes and different raw materials. The most common, first generation, biodiesel is produced by methanolysis of vegetable oils using basic or acid homogeneous catalysts. The use of vegetable oils for biodiesel production raises serious questions about biodiesel sustainability. Used cooking oils and animal fats can replace the vegetable oils in biodiesel production thus allowing to produce a more sustainable biofuel. Moreover, methanol can be replaced by ethanol being totally renewable since it can be produced by biomass fermentation. The substitution of homogeneous catalyzed processes, nowadays used in the biodiesel industry, by heterogeneous ones can contribute to improve the biodiesel sustainability with simultaneous cost reduction. From the existing literature on biodiesel production, it stands out that several strategies can be adopted to improve the sustainability of biodiesel. A literature review is presented to underline the strategies allowing to improve the biodiesel sustainability.

Calcium diglyceroxide (CaD) was used as the catalyst for biodiesel production through oil methanolysis. It was evaluated its catalytic behavior, its air expo- sure tolerance, and the Ca leaching. CaD catalyst was synthesized from food waste scallop shell derived CaO (obtained by calcination at 900 °C) by contacting with a mixture of equal volumes of glycerin and methanol at 65 °C for 2 h. The CaO obtained by calcination of scallop shell was used as reference catalyst. In standard reaction conditions (2.5 h, methanol reflux temperature, 5 wt% (oil basis) catalyst loading, and methanol:oil = 12:1 moral ratio), CaD presented lower catalytic activity than CaO (FAME yield of 92% against 99%, respectively). 24 h repined CaD presented improved catalytic behavior probably due to the formation of surface Ca −OH groups, achieving 96% of FAME yield. Thermogravimetry (TG) data showed that inorganic residue was larger for biodiesel than for glycerin, being CaD catalyst more soluble than CaO. Data showed that CaD is unstable under reaction conditions, suffering leaching, but the absence of Matter Organic Non-Glycerol (MONG) in the glycerin phase allows to neglect the homogeneous contribution of the leached catalyst. CaD formation during reaction contributes to FAME contamination with Ca and promotes catalyst deactivation thus being an undesired occurrence.

Aiming to achieve a more sustainable and competitive biodiesel production process, the co-produced glycerin must be valorized. Since the glycerin market is saturated due to the growth of the biodiesel industry, glycerin can be used in a more effective way, such as the conversion to oxygenated additives for diesel. Acetins production by glycerin acetylation with acetic acid over acid heterogeneous catalysts was studied. Sulfonated sugar catalysts were prepared from crude glycerin and pure glucose and used to catalyze the glycerin acetylation. Scanning Electron Microscopy with Energy Dispersive Spectroscopy assessed the morphology and chemical composition, of fresh and post-reaction catalysts. Infrared spectroscopy with attenuated total reflection accessory for spectra acquisition was used to identify the functional groups on the sulfonated carbon catalysts whereas, the degree of graphitization was assessed by Raman Spectroscopy. Acetylation reaction was performed at the reflux temperature (120 °C), using a molar ratio acetic acid/glycerin of 7.8 and a catalyst loading of 10 wt % (glycerin weight basis). The best catalytic performance was exhibited by the glucose derived catalysts prepared with a higher content of sulfuric acid (H2SO4/Glucose = 2 and 4; Glucose_1:2 and Glucose_1:4), achieving 31.3% and 32.5% of triacetylglycerol after 5 h of reaction. For the glycerin based catalysts, the highest triacetylglycerol selectivity (24.1%) was also obtained using the sample prepared with the highest content of sulfuric acid (molar ratio H2SO4/Glycerin = 2; Glyc_1:2). The catalysts showed high stability with a slow rate of sulphonic species leaching into the reaction medium.

Fatty Acid Methyl Esters (FAME) were produced from lard/soybean oil (SBO) mixtures using a calcium-based heterogeneous catalyst. The green catalyst was prepared by scallop shell calcination at a relatively low temperature (800 °C) to minimize energy consumption. Images from Scanning Electron Microscopy showed agglomerates of a few tens micrometers with rhombohedral calcite crystallites studded with lime. X-ray diffractogram of fresh catalyst presented overlapped patterns of calcite and lime In tested conditions (methanol reflux temperature, 5% (fat mass basis), methanol/fat = 12 molar ratio, and 150 min), the FAME yield reached 95% (mass) with SBO. However, only 75% FAME yield was obtained from pure lard since the active sites of the catalyst were partially neutralized by lard acidity. Co-processing lard/SBO mixtures attenuated the undesirable fat acidity drawback allowing FAME yields around 90% for mixtures containing less than 50% (mass) of lard. The low-grade fat content of the processed mixture showed no impact on the glycerin quality. Co-processing lard/SBO is a smart strategy to overcome the low-grade fats acidity in biodiesel production process thus providing a more sustainable biodiesel production route.

In this study, the effect of low frequency ultrasound assisted solvent extraction was assessed for three species of microalgae ( Chlorella vulgaris , Nannochloropsis oculata and Scenedesmus obliquus ). The microalgae contain a wide range of compounds (carbohydrates, proteins, lipids and pigments), which after extraction, can have several benefits, such as conversion of lipids into biofuel. Pure and binary (2:1 v/v) mixtures of high volatile solvents and relative low toxicity ( n -hexane, chloroform, 2-butanol, isopropanol, ethanol and methanol) were used. Low concentration suspensions microalgal/solvent (0.03 g/mL) was sonicated for 180 min at 50/60 Hz at 60 °C using a reflux column to avoid solvent evaporation. The extent of the extraction procedure was assessed by weighing of extracts, after solvents evaporation, and by comparing the thermal degradation (under air by thermogravimetric analysis) and Fourier transformed infrared spectroscopy (FTIR) profiles of raw and leftover microalgae. Additionally, the raw and leftover microalgae and the liquid extract were characterized by FTIR. A scanning electron microscopy (SEM) was used to evaluate the effect of ultrasound on the microalgae morphology. Energy requirements were measured for the solvent extraction procedure and compared with literature data using other methods. The results reveals that (i) for all the analyzed microalgae the best extraction was achieved using the binary solvent n -hexane:isopropanol; (ii) the C. vulgaris showed the lowest yield of liquid extract; (iii) the absence of cell disruption, but a slight swelling, was observed by SEM; and (iv) the energy requirements of this method are roughly 0.15 MJ/g dry microalgal , which is lower than previous soxhlet extraction, using n -hexane as a solvent, and supercritical fluid extraction.

Woody biomass can be converted into green fuels by advanced conversion technologies such as gasification and pyrolysis. Due to the complexity of woody biomass, the thermochemical decomposition mechanisms are complex and the knowledge of pyrolysis kinetics is mandatory for optimization of the process and reactor design of commercial scale biorefineries. Pyrolysis kinetics of short rotation coppice (SRC) poplar biomass (nine different clones) was studied using non-isothermal thermogravimetry. By using differential thermogravimetry data, obtained for heating rates of 10–50 K/min, the Kissinger model-free methodology showed activation energies in the range 108–320 kJ/mol, similar to those reported in the literature for cellulose pyrolysis. Isoconversional approaches of Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) obtained similar values of activation energy (81–301 kJ/mol and 90–306 kJ/mol, respectively. The kinetics parameters obtained by the FWO and KAS methods were higher than data reported in the literature for other biomasses, and a correlation between activation energy and the lignin content of the biomass samples was found. The pyrolysis activation energy seems to have no significant effect on the pyrolysis product yields, probably because, under the tested conditions (fixed bed reactor, 773 K), pyrolysis was controlled by mass and/or heat transfer limitations instead of kinetics control.

Fast pyrolysis trials of wheat straw were performed in a pilot plant featuring a screw reactor and two stage condensation system. Trials differed in the moisture content of the used biomass (1.2%, 9.2%, and 23.6%) and the sweeping gas flowrate. Higher moisture feedstock seems to lead to higher bio-oil production but the largest organic liquid yield occurred at intermediate feedstock moistures. Increasing the sweeping gas flow rate at the system leads to a higher liquid yield richer in organics. Based on these results it is concluded that the highest organic liquid yield is not observed for dry feedstock because the missing water vapour leads to longer hot vapour residence time, favouring secondary gas phase cracking reactions. Information and yields obtained at the pilot were scaled up to industrial scale (500 kg h−1 of feedstock) and used to construct an Aspen Plus® model that can be used to estimate heat availability in different parts of the system as well as simulate a dryer that would employ available internal process heat. This model was used to investigate the impact of using moister feedstock in the process. Enough heat is available for drying moist feedstock by using flue gas of the heat carrier loop in a different manner as in the current design.

Aiming the decarbonization of the transport sector, biodiesel, obtained by alcoholysis of oils or animal fats, is currently mixed with conventional fossil diesel. For this purpose, biodiesel has to comply with the established quality standards and, therefore, the production process comprises purification steps, which need huge volumes of water. Thus, the biodiesel purification procedure must be improved in order to provide a greener and low-cost renewable fuel. Biodiesel (FAME) produced by methanolysis of soybean and waste frying oils over a heterogeneous calcium-based catalyst was purified by dry washing, using commercial silica sorbent (Sipernat 22 from Evonik). ATR-FTIR spectra of post-purification sorbents showed that silica was effective to remove unreacted oil species, glycerin and Ca soap from biodiesel and, contrary to the previously reported in the literature, it was also able to remove leached calcium from the biodiesel. For both feedsotcks, the highest purity was reached for the sorption test carried out at 45 ℃ during 60 min. Sorbent regeneration was evaluated using acetone, methanol, and isopropanol alcohols at room temperature during short contact time (5 min for 1 g of sorbent and 20 mL of solvent). All the tested solvents were effective to remove the adsorbed species from silica surface.

This paper summarizes the results of a research on the influence of the poisoning of the SCR catalyst on its structure. Samples of commercially available SCR catalysts were exposed to real flue gases inside a pulverized coal boiler co-firing coal and biomass. The catalysts were investigated by SEM-EDS, XRD, AAS, UV–vis and 1-butene isomerization as a test reaction. Additionally, ash collected from the catalysts was characterized. The obtained results showed a decrease in the activity by ash and alkali metals originating from biomass. Neither the structural changes in the support nor the changes in the oxidation state and distribution of vanadium were observed during the entire testing period. The acidity of the catalyst, operated for the shortest period (2270 h), increased due to the formation of sulfate species arising from the presence of SO 2 in the flue gases. The role of sulfate species and alkali cations in poisoning of catalytic sites is discussed.

The combined use of ESI-MS (electrospray ionization-mass spectrometry) and theoretical calculations for the determination of citrate:metal (metal = Cu and Fe) structures are reported. Mass spectrometry allowed to determine the stoichiometry 1:1 and 2:1 of the complexes, corroborating the theoretical calculations. The species found in the ratio 2:1 had their calculated structures readjusted, from what was originally simulated, since the deprotonation of citric acid differed from what was before simulated. The thermodynamic stability (ΔH(aq.)0) of the complexes optimized at the B3LYP/LANL2DZ level was more exoenergetic than for the complexes found by the PM6 semi-empirical method.

Iron molybdates are common industrial catalysts for methanol oxidation. The role of Mo excess, usually present in the catalyst formulation still doubtful. Some authors claim a stability effect whereas others claim that surface MoO 3 , segregated from bulk, is the active phase. In order to clarify the role of Mo excess on the catalytic performances, catalysts were prepared by Mo surface loading of stoichiometric Fe 2 (MoO 4 ) 3 . No crystalline MoO 3 was detected even for the sample prepared with five monolayers (maximum number) of MoO 3 . XPS data reveals a Mo surface enrichment even for the stoichiometric mixed oxide sample. All the samples presented Mo/Fe atomic ratio higher than the stoichiometric value (1.5). Adding of MoO 3 monolayers seems to promote surface aggregation of Mo species. Catalytic data showed that Mo surface enrichment of the stoichiometric phase leads to an increase of formaldehyde yield for loadings higher than 0.5 monolayers. The observed behavior seems to result from a compromise between the higher catalytic activity of the Fe 2 (MoO 4 ) 3 phase and the lower activity but higher selectivity of the MoO 3 phase. A cooperative effect between the MoO 3 and the molybdate phase seems to dictate the catalytic performances.

The combined use of ESI-MS, FTIR-ATR and theoretical calculations for the determination of metal-citrate (metal = Cd and Pb) structures are reported. Mass spectrometry allowed to determine the stoichiometry 1:1 and 2:1 of the complexes, corroborating the theoretical calculations. The species found in the ratio 2:1 had their molecular structures readjusted, since the deprotonation of citric acid differed from what was simulated. The calculations of thermodynamic stability (ΔH0(aq.)) for the complexes obtained by B3LYP/LANL2DZ were more exoenergetic than those found by PM6. However, for both methods, the stability of the complexes follows a trend, that is, the lowest-energy isomers in PM6 are also the most stable in B3LYP/LANL2DZ. The infrared analysis suggested that carboxyl groups are complexation sites and hydrogen bonds can help in the stability of the complexes. The vibrational frequencies in B3LYP/LANL2DZ had a good correlation with the experimental infrared results.

The combined use of ESI-MS and theoretical calculations for the determination of zinc:citrate structures are reported. Mass spectrometry allowed to determine the stoichiometry 1:1 and 2:1 of the complexes, corroborating the theoretical calculations. The species found in the ratio 2:1 had their molecular structures readjusted, since the deprotonation of citric acid differed from what was simulated. The thermodynamic stability (ΔH0(aq.)) of the complexes optimized at the B3LYP/LANL2DZ level was more exoenergetic than for the complexes found by the PM6 semi-empirical method.

Biodiesel production by methanolysis of semi-refined rapeseed oil was studied over lime based catalysts. In order to improve the catalysts basicity a commercial CaO material was impregnated with aqueous solution of lithium nitrate (Li/Ca = 0.3 atomic ratio). The catalysts were calcined at 575 °C and 800 °C, for 5 h, to remove nitrate ions before reaction. The XRD patterns of the fresh catalysts, including the bare CaO, showed lines ascribable to CaO and Ca(OH) 2 . The absence of XRD lines belonging to Li phases confirms the efficient dispersion of Li over CaO. In the tested condition ( w cat / w oil = 5%; CH 3 OH/oil = 12 molar ratio) all the fresh catalysts provided similar biodiesel yields (FAME >93% after 4 h) but the bare CaO catalyst was more stable. The activity decay of the Li modified samples can be related to the enhanced, by the higher basicity, calcium diglyceroxide formation during methanolysis which promotes calcium leaching. The calcination temperature for Li modified catalysts plays an important role since encourages the crystals sinterization which appears to improve the catalyst stability.

Simvastatin (SV) is a widely used drug for the treatment of hypercholesterolemia in humans. Nevertheless, serious efforts are still being made to develop new SV formulations with, for example, improved tabletability or bioavailability properties. These efforts frequently involve heating the compound well above ambient temperature or even fusion. In this work, the thermal stability of solid SV under different atmospheres was investigated by using isothermal tests in glass ampules, differential scanning calorimetry, and Calvet- drop microcalorimetry experiments. These tests were combined with analytical data from diffuse reflectance infrared Fourier-transform spectroscopy and liquid chromatography coupled with tandem mass spectrometry or Fourier transform ion cyclotron resonance mass spectrometry (LC-FT-ICR-MS). No decomposition was observed when the sample was kept at a temperature ≤373 K under N2 or reduced pressure (13.3 Pa) atmospheres. Thermal degradation was, however, observed for temperatures ≥353 K in the presence of pure or atmospheric oxygen. The nature of the two main oxidative degradation products was determined through MS/MS experiments and accurate mass measurements of the precursor ions using FT-ICR-MS. The obtained results indicated that the decomposition process involves the oxidation of the hexahydronaphthalene fragment of SV. C

Egg shells, shellfish shells and cuttlefish bones, high calcium content alimentary wastes, were used to prepare CaO sorbents for CO 2 capture. The materials were prepared by a simple procedure including two steps: crushing and calcination at 900 °C. Fine powders displaying chalky-white to pale grey-green shades were obtained depending on the starting material. All the prepared sorbents were microcrystalline limes containing various trace elements. The CO 2 sorption ability of the obtained lime materials was assessed using cycle carbonation/calcination tests by thermogravimetry. The CO 2 sorption profiles showed two regions: an initial region controlled by chemical reaction and a second region with diffusional control. The rate of chemical reaction of carbonation was almost invariant with the nature of the biomaterial used to produces the sorbent. The decarbonation (calcination step) was much faster than the carbonation for all the examined sorbents and also almost invariant with the sample. The diffusion rate depends on the calcite film thickness formed during chemical reaction controlled region. Results showed that alimentary wastes with high calcium content can be used to produces CO 2 sorbents thus contributing to mitigate the anthropogenic carbon and the environment contamination with alimentary wastes.

Biodiesel production from semi-refined oils (SRO) and waste frying oils (WFO) was studied using commercial CaO as heterogeneous catalyst. The methan- olysis tests were carried out in mild reaction conditions (62 C, atmospheric pressure). With such conditions, SRO (soybean and rapeseed) allowed to produce a biodiesel containing 97-98 % of methyl esters (FAME), whereas WFO only provided 86-87 % of FAME. The lower FAME yield for WFO oil is ascribable to the partial neutralization of the catalyst by free fatty acids. Also, soaps formation from the WFO oil reduced the weight yield of the oil phase (containing FAME) obtained and increased the MONG content of the glycerin phase. The catalysts stability tests showed high stability even when WFO oil was processed. Catalytic tests performed with blends of WFO/semi- refined oils showed blending as a good strategy to process low value raw oils with minor decay of the catalyst performance. Both WFO and semi-refined oils showed S-shape kinetics curves thus discarding significant differences of the reaction mechanisms.

Lime is pointed out as an effective catalyst for biodiesel production by oil methanolysis. Several Ca phases are formed during reaction. Each Ca phase has different contribution to the catalyzed process. Using CaO as a catalyst, S shape kinetics curve was observed and the induction period can be ascribed to the Ca(OH) 2 formation. When Ca(OH) 2 , prepared by contacting CaO with H 2 O, is used as catalyst the initial period with a slow rate of transesterification has almost vanished. Besides, if the catalyst surface is totally converted into methoxide species the induction period is longer than the analogous obtained with CaO. This is an indication that the methoxide species strongly bonded to Ca are less reactive. The calcium diglyceroxide material (CaO_diglyc), prepared by contacting CaO with a mixture of methanol and glycerol, displays a totally different kinetics curve with no induction period. The faster kinetics and the Ca species detected in the glycerin phase seem to underline a non-negligible homogeneous process contribution. The characterization of the post-reaction catalysts underlines the relevance of the surface and bulk catalyst modifications. Calcium hydroxide can be pointed out as the active phase whereas calcium diglyceroxide is responsible for the catalyst deactivation due to calcium leaching.