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The effect of pyrolysis temperature on the morphology, bulk and surface chemistry of cellulose, xylan and lignin chars has been examined. Chars were produced between 300 and 700 °C. Raman, X-ray photoelectron, nuclear magnetic resonance spectroscopic techniques, scanning electron microscopy and surface area analysis were used to characterize each sample. Formation of polyaromatic structures were found to be prevalent at 400 °C for both cellulose and lignin chars, and showed development at 300 °C for Xylan. The low A bands identified in the lignin char produced at 400 °C indicate that crosslinking at low temperatures preferentially forms hexagonal or larger rings. Aromatic condensation increased until 500 °C, and remained stable up to 700 °C. The sharp drop in oxygen content as temperature is increased up to 500 °C and the formation of ether (C-O-C) groups indicates that oxygen is a primary reaction component for crosslinking and polycondensation. Despite the considerable increase in ring size for char produced at 700 °C compared to 500 °C, only very mild loss of oxygen is identified, suggesting that C-C bonds are forming with minimal oxygen mediation The increased broadness of the NMR peak and the Raman G band suggest that at these temperatures the increase in ring size occurs largely in a 3 dimensional manner rather than planar with contributions from non-hexagonal rings and out-of-plane distortion. By comparing the NMR dephasing data to the I(D)/I(G) ratio an approximate relation between this Raman data and cluster size has also been derived. [ABSTRACT FROM AUTHOR]

Compost is used in bioretention systems to improve soil quality, water infiltration, and retention of contaminants. However, compost contains dissolved organic matter, nitrate, and phosphorus, all of which can leach out and potentially contaminate ground and surface waters. To reduce the leaching of nutrients and dissolved organic matter from compost, biochar may be mixed into the bioretention systems. Our objective was to test whether biochar and co-composted biochar mixed into mature compost can reduce the leaching of organic carbon, nitrogen, and phosphorus. There was no significant difference between the effects of biochar and co-composted biochar amendments on nutrient leaching. Further, biochar amendments did not significantly reduce the leaching of dissolved organic carbon, nitrate, and phosphorus as compared to the compost only treatment. The compost–sand mix was the most effective in reducing nitrate and phosphorus leaching among the media. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis of beech wood particles (0.3 and 14mm). [•] The yield of pyrolytic lignin decreased as particle size increased. [•] Two different pyrolysis regimes were confirmed between 0.3 and 14mm. [•] Secondary reactions and mass transfer limitations lead to more char. [Copyright &y& Elsevier]

Lipids are a biorefinery platform to prepare fuel, food and health products. They are traditionally obtained from plants, but those of microbial origin allow for a better use of land and C resources, among other benefits. Several (thermo)chemical and biochemical strategies are used for the conversion of C contained in lignocellulosic biomass into lipids. In particular, pyrolysis can process virtually any biomass and is easy to scale up. Products offer cost-effective, renewable C in the form of readily fermentable molecules and other upgradable intermediates. Although the production of microbial lipids has been studied for 30 years, their incorporation into biorefineries was only described a few years ago. As pyrolysis becomes a profitable technology to depolymerize lignocellulosic biomass into assimilable C, the number of investigations on it raises significantly. This article describes the challenges and opportunities resulting from the combination of lignocellulosic biomass pyrolysis and lipid biosynthesis with oleaginous microorganisms. First, this work presents the basics of the individual processes, and then it shows state-of-the-art processes for the preparation of microbial lipids from biomass pyrolysis products. Advanced knowledge on separation techniques, structure analysis, and fermentability is detailed for each biomass pyrolysis fraction. Finally, the microbial fatty acid platform comprising biofuel, human food and animal feed products, and others, is presented. Literature shows that the microbial lipid production from anhydrosugars, like levoglucosan, and short-chain organic acids, like acetic acid, is straightforward. Indeed, processes achieving nearly theoretical yields form the latter have been described. Some authors have shown that lipid biosynthesis from different lignin sources is biochemically feasible. However, it still imposes major challenges regarding strain performance. No report on the fermentation of pyrolytic lignin is yet available. Research on the microbial uptake of pyrolytic humins remains vacant. Microorganisms that make use of methane show promising results at the proof-of-concept level. Overall, despite some issues need to be tackled, it is now possible to conceive new versatile biorefinery models by combining lignocellulosic biomass pyrolysis products and robust oleaginous microbial cell factories. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis produces bio-oil for further upgrading to electricity, (transportation) fuels and chemicals. [•] Pyrolysis fits well into the existing fossil infrastructure (logistics and refining). [•] Several demonstration units (1–5ton/hours) considered. [•] Multilevel research from chemistry of the cell wall to optimization of whole factory. [•] Fermentation of pyrolytic sugars explores the interface between thermochemistry and biotechnology. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports the production of lipids from non-hydrolyzed levoglucosan (LG) by oleaginous yeasts Rhodosporidium toruloides and Rhodotorula glutinis. Enzyme activity tests of LG kinases from both yeasts indicated that the phosphorylation pathway of LG to glucose-6-phosphate existed. The highest enzyme activity obtained for R. glutinis was 0.22U/mg of protein. The highest cell mass and lipid production by R. glutinis were 6.8 and 2.7g/L, respectively from pure LG, and 3.3 and 0.78g/L from a pyrolytic LG aqueous phase detoxified by ethyl acetate extraction, rotary evaporation and activated carbon. This corresponded to a lipid yield of 13.5wt.% for pure LG and only 3.9wt.% for LG in pyrolysis oil. [Copyright &y& Elsevier]

Abstract: The presence of very reactive C1–C4 molecules adversely affects the quality bio-oils produced from the pyrolysis of lignocellulosic materials. In this paper a scheme to produce lipids with Cryptococcus curvatus from the carboxylic acids in the pyrolytic aqueous phase collected in fractional condensers is proposed. The capacities of three oleaginous yeasts C. curvatus, Rhodotorula glutinis, Lipomyces starkeyi to ferment acetate, formate, hydroxylacat-aldehyde, phenol and acetol were investigated. While acetate could be a good carbon source for lipid production, formate provides additional energy and contributes to yeast growth and lipid production as auxiliary energy resource. Acetol could slightly support yeast growth, but it inhibits lipid accumulation. Hydroxyacetaldehyde and phenols showed high yeast growth and lipid accumulation inhibition. A pyrolytic aqueous phase with 20g/L acetate was fermented with C. curvatus, after neutralization and detoxification to produce 6.9g/L dry biomass and 2.2g/L lipid. [Copyright &y& Elsevier]

Abstract: This paper describes the use of Differential Scanning Calorimetry (DSC) to evaluate the impact of varying mix ratios of bio-oil (pyrolysis oil) and bio-diesel on the oxidation stability and on some cold flow properties of resulting blends. The bio-oils employed were produced from the semi-continuous Auger pyrolysis of pine pellets and the batch pyrolysis of pine chips. The bio-diesel studied was obtained from poultry fat. The conditions used to prepare the bio-oil/bio-diesel blends as well as some of the fuel properties of these blends are reported. The experimental results suggest that the addition of bio-oil improves the oxidation stability of the resulting blends and modifies the crystallization behavior of unsaturated compounds. Upon the addition of bio-oil an increase in the oxidation onset temperature, as determined by DSC, was observed. The increase in bio-diesel oxidation stability is likely to be due to the presence of hindered phenols abundant in bio-oils. A relatively small reduction in DSC characteristic temperatures which are associated with cold flow properties was also observed but can likely be explained by a dilution effect. [Copyright &y& Elsevier]

Abstract: This paper describes the production and fuel properties of fast pyrolysis oil/bio-diesel blends. The bio-oils used in this study were produced from the fast pyrolysis of woody biomasses, oil mallee and pine. The bio-diesel employed was derived from canola vegetable oil. The conditions used to prepare the bio-oil/bio-diesel blends, as well as some of the fuel properties of the resulting bio-diesel rich phase, are reported. The experimental results show that the solubility of fast pyrolysis oils in bio-diesel is not as high as was previously reported for decanted oils obtained by Auger pyrolysis. The carboxylic acids, mono-phenols, furans and lignin derived oligomers were the compounds most soluble in bio-diesel, while the sugars, on the other hand, showed poor solubility. Although the presence of phenols enhances the oxidation stability of the bio-diesel rich phases, other fuel properties deteriorate. For example, the content of solid residues increased primarily because of the solubilisation of lignin derived oligomers, which were quantified by UV-fluorescence. Concentrations as high as 3.5mass % of these compounds were observed in the bio-diesel rich phase. The solubility of bio-oil in bio-diesel was enhanced by using ethyl acetate/bio-diesel blends. Some fuel properties of the bio-diesel rich phase, after the removal of ethyl acetate, are reported. [Copyright &y& Elsevier]

The efficient configuration of supply chains is a current challenge for deploying sustainable aviation fuel (SAF), a key element of the decarbonization of the aviation industry. Despite advances in the modeling of biorefinery location siting, transportation network design, and co-products use, current supply chains and business models for renewable fuel production do not result in costs that are competitive with fossil fuels. Various elements for process efficiency enhancement, risk mitigation, total cost reduction, and profit maximization have been studied in supply chain design. In this work, we study the conceptual components needed for the design and analysis of supply chains. We emphasize the impact that monetization of environmental and social services could have on the overall viability of SAF production. The current state of the supply chain configuration of SAF is compared with other supply chain and value-chain strategies, mainly: (1) lean, used for staple commodities, (2) agile, intended for innovative products and services, (3) green, meant to reduce the environmental impacts, and (4) risk-adverse, used to minimize supply risk disruptions. A summary of models and simulation approaches used to synthesize and solve supply chain problems is included. Our review highlights the uniqueness of the supply chain for SAF and proposes ways to enrich the existing approach with methods used by other industries. The SAF business model could be improved by including ecosystem and social services to generate additional revenue. New strategies accounting for the dynamic interactions between the components of the supply chain of SAF, including services, are needed. [Display omitted] • The supply chain of SAF has centered strategic decisions on efficiency enhance. • The SAF business model is not suited to a single supply chain strategy. • Ecosystem and social services as revenue streams may reduce SAF selling price. • It is needed to develop a systemic analysis of SAF production, including services revenues. • Value chain configuration needs dynamic simulations to estimate potential productions. [ABSTRACT FROM AUTHOR]

• Small quantity of oxygenated compounds in jet fuel is responsible for poor thermal stability. • Quantification of trace oxygenated species is conducted by solid phase extraction (SPE) • Fuel matrix influences Rhodamine B (Rh-B) UV fluorescence quenching. • A new method based on SPE and Rh-B UV fluorescence quenching is developed to identify oxygenate compounds in jet fuels. • The method developed allows the fast detection of trace oxygenated molecules in jet fuel at operational field conditions. The trace-oxygenated compounds in jet fuel reduce thermal stability. The identification and quantification of oxygenated species is typically conducted using solid phase extraction (SPE) followed by the analysis of extracted molecules by GC–MS. Our experimental results confirmed that SPE followed by methanol extraction of phenolic compounds could separate and recover quantitatively the oxygenated polar species from the fuel; however, the method is labor-intensive. The UV-Fluorescence of methanol-soluble SPE phenol doped jet fuels showed a linear response with phenol concentration. Although in general the UV-fluorescence response of phenols in jet fuel is linear, differences in response were observed depending on the type of standard studied. The differences in response can be explained by the nature of side functional groups in phenol with quenching effects. Fluorescence quenching with Rhodamine B (Rh-B) was explored for the direct analysis of phenols in jet fuels. The strong binding ability of phenols on Rh-B explain the quenching effect observed. However, studies conducted with other jet fuels indicates that nature of the fuel matrix also influences Rhodamine B (Rh-B) UV quenching. To address this issue, a new method that removes oxygenated compounds by SPE and that compares the Rhodamine-B spectra before and after SPE was developed. [ABSTRACT FROM AUTHOR]

Catalytic hydrotreatment followed by products isomerization is an effective technology to convert vegetable oil to a green fuel composed of straight and branched chain aliphatic hydrocarbons. The content of aromatics in this fuel is very low. In this paper we study the co-hydrotreatment of vegetable oil and tires oil in the presence of a CoMo/Al 2 O 3 catalyst as a way of utilizing existing infrastructure created for vegetable oil processing for tire oil up-grading in order to obtain fuel cuts with aromatics. Hydrotreatment studies with different vegetable oil/tires oil blend ratios were conducted. The yield and composition of the resulting hydrotreated oils are reported. Aliphatic hydrocarbons ranging from C7 to C20 derived from vegetable oils and aromatics from C6 to C16 derived from the tire oil were identified as products. The resulting oils were then successfully distilled into naphtha, kerosene, diesel and gas oil cuts. The yield, chemical composition and the fuel properties of the transportation fuel cuts obtained are reported and compared with commercial petro derived fuels. [ABSTRACT FROM AUTHOR]

Efficient conversion of all components in lignocellulosic biomass is essential to realizing economic feasibility of biorefineries. However, lignin cannot be fermented using biochemical routes. Furthermore, high lignin and high ash residues from simultaneous saccharification and fermentation (SSF) is difficult to thermochemically process due to feed line plugging and bed agglomeration. In this study a corn stover SSF digester residue was thermally pretreated at 300 °C for 22.5 min and gasified in a fluidized bed gasifier to study the effect of thermal pretreatment on its processing behavior. Untreated, pelletized SSF residue was gasified at the same conditions to establish the baseline processing behavior. Results indicate the thermal pretreatment process removes a substantial portion of the polar and non-polar extractives, with a resultant increase in the concentration of lignin, cellulose, and ash. Feed line plugging was not observed, although bed agglomeration occurred at similar rates for both feedstocks, suggesting that overall ash content is the most important factor affecting bed agglomeration. Benzene, phenol, and polyaromatic hydrocarbons in the tar were present at higher concentrations in the treated material, with higher tar loading in the product gas. Total product gas generation is lower for the treated material, although overall gas composition does not change. [ABSTRACT FROM AUTHOR]

The objective of this research was to investigate the effects of the conditions of hot water extraction (HWE) on abundance, properties, and structure of lignin depolymerization products. HWE of extracted softwood (ponderosa pine) was conducted using temperatures from 140 to 320 °C for 90 min. HWE materials were then subjected to a soxhlet extraction process using dichloromethane (DCM). The composition and molecular weight of this DCM-soluble material was conducted using semi-quantitative Py-GC/MS and ESI/MS, which showed that this material is rich in lignin with low molecular weight (<1200 g mol −1 ) and low polydispersity (∼1.4). The highest yield of this material (∼4.2%) was obtained in material processed at 260 °C. Py-GC/MS of the solid fraction after the DCM process showed a progressive reduction of products of the pyrolysis of lignin as the HWE temperature increased. This finding suggests that the lignin content in the solid decreased due in part to migration from the cell walls and middle lamella to the particles surfaces, particularly the inner surface of the cells. SEM and AFM techniques helped to visualize the ability of this DCM-soluble extract to adhere to cellulosic fibers. Therefore, this lignin-rich material presents properties that depend on the conditions of the operation. Results indicate that during HWE it is possible to control the process parameters to limit or increase the amount of DCM-soluble lignin and its properties as required for downstream processes. [ABSTRACT FROM AUTHOR]

A well-defined methodology for constructing appropriate atomistic representations of biochar will aid in visualizing the structural features and elucidating biochar behavior with molecular dynamics (MD) simulations. Such knowledge will facilitate engineering biochars tailored to specific applications. To achieve this goal, we adapted modeling strategies applied in coal science by employing multi-cross-polarization 13C nuclear magnetic resonance, ultimate analysis, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy to identify functional groups. Helium density, surface area, and porosity were used to assess structural features. Biochar's aromatic cluster size distribution was proposed based on data from the benzene polycarboxylic acid method. The computational framework reduces bias by incorporating chemical information derived from density functional theory, reactive MD simulations, and advanced characterization data. The construction approach was successfully applied to cellulose biochars produced at four temperatures, obtaining independent representations with a relative error on the atomic contents of <10 % for oxygen and nitrogen and <5 % for carbon and hydrogen. The atomistic representations were validated using X-ray diffraction, electron spin resonance data, and laser desorption/ionization Fourier-transform ion cyclotron resonance-mass spectrometry. The code will assist others in overcoming structural creation barriers and enable the utilization of the generated structures for further simulations. [Display omitted] • Available code for creating large-scale atomistic models, capturing chemical and physical features. • A novel approach proposes the aromatic cluster size distribution of biochar. • Atomistic representations are validated with experimental and theoretical data. • The arrangement of aromatic size distributions aids in surface area and pore development. [ABSTRACT FROM AUTHOR]

It is crucial for the environment, the economy, and society to create low-cost adsorbents from renewable resources to remove phosphate from aqueous effluents. Here, two renewablecarbon and nitrogen sources (Douglas fir and Chitosan) were used to produce engineered N -doped biochars modified with Mg for PO 4 3− adsorption. Mg–N doped biochars were prepared using an impregnation-carbonization process. A central composite experimental design was used to select combinations of independent variables to maximize phosphate adsorption capacity. Phosphate adsorption isotherms were fitted with Langmuir and Freundlich isotherms. The biochar produced at 700 °C, 12 wt % MgCl 2, and Douglas Fir/Chitosan ratio: 1/1, which has the highest PO 4 3− adsorption capacity, was further studied. Proximate analysis, elemental composition, surface area, pore size distribution, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX) were used to characterize this biochar. This biochar has an adsorption capacity of 112.4 mg PO 4 3−/g char. Its phosphate adsorption rate was adjusted to a pseudo-second-order kinetic model. The phosphate adsorption capacity of the biochar produced was comparable with the most effective biochar reported in the literature. [Display omitted] • Phosphate adsorption was improved when chitosan and Mg added. • Response surface approach was used to assess the thermochemical conditions. • A relationship between N -functionalities and Mg was observed during adsorption. • The utilized biochar from renewable resources can be used as a slow fertilizer. [ABSTRACT FROM AUTHOR]

Abstract: This study aims to investigate the effects of biomass particle size (0.18–5.6mm) on the yield and composition of bio-oil from the pyrolysis of Australian oil mallee woody biomass in a fluidised-bed reactor at 500°C. The yield of bio-oil decreased as the average biomass particle size was increased from 0.3 to about 1.5mm. Further increases in biomass particle size did not result in any further decreases in the bio-oil yield. These results are mainly due to the impact of particle size in the production of lignin-derived compounds. Possible inter-particle interactions between bio-oil vapour and char particles or homogeneous reactions in vapour phases were not responsible for the decreases in the bio-oil yield. The bio-oil samples were characterised with thermogravimetric analysis, UV-fluorescence spectroscopy, Karl–Fischer titration as well as precipitation in cold water. It was found that the yields of light bio-oil fractions increased and those of heavy bio-oil fractions decreased with increasing biomass particle size. The formation of pyrolytic water at low temperatures (<500°C) is not greatly affected by temperature or particle size. It is believed that decreased heating rates experienced by large particles are a major factor responsible for the lower bio-oil yields from large particles and for the changes in the overall composition of resulting oils. Changes in biomass cell structure during grinding may also influence the yield and composition of bio-oil. [Copyright &y& Elsevier]

Nitrogen-doped materials are known to possess unique functional properties, making these materials potentially useful for environmental applications, heterogeneous catalysis, and electronics. In this paper we constructed first principles-based models of various polyaromatic structures containing N functionalities to better understand the effect of these functional groups on char Raman spectra. The presence of N functional groups induces active vibrations in the regions between 1400 and 1550 cm−1 and 1605-1650 cm−1. We used these insights to inform the deconvolution of N-doped cellulose char produced between 350 and 700 °C using cellulose/melamine blends 2:1. A consistent increase in the intensity of the D and G bands is observed with temperature, which is related to an increase in size of the aromatic cluster. A consistent decrease in the A (the valley region) band is related to the loss of heteroatoms (mainly N and O) as the carbonization temperature increases from 350 to 700 °C. Although the modeling results reported in this manuscript are used to inform the deconvolution of N-doped char Raman spectra, they are also relevant to study other nanocarbon-based materials. Image 1 [ABSTRACT FROM AUTHOR]

Quantifying the content of surface nitrogen and oxygen containing functional groups in amorphous nitrogen doped carbons via deconvolution of C 1s x-ray photoelectron (XPS) spectra remains difficult due to limited information in the literature. To improve the interpretation of XPS spectra of nitrogen-doped carbons, the C 1s, N 1s and O 1s core level energy shifts have been calculated for various nitrogenated carbon structures via DFT. Furthermore, we propose an expanded method to improve the self-consistency of the XPS interpretation based on a seven-peak C 1s deconvolution (3 C–C peaks, 3 C–N/-O peaks, and π-π∗ transition peaks). With the DFT calculations, spectral components arising from surface-defect carbons could be distinguished from aromatic sp2 carbon. The deconvolution method proposed provides C/(N + O) ratios in very good agreement (error less than 5%) with those obtained from total C 1s, N 1s and O 1s peaks. Our deconvolution strategy provides a simple guideline for obtaining high-quality fits to experimental data on the basis of a careful evaluation of experimental conditions and results. Image 1 [ABSTRACT FROM AUTHOR]

Nitrogen functionalization of graphene significantly enhances the physical and chemical properties of graphitic materials, increasing their applicability as sorbents, heterogeneous catalysts, and electronic components. Being able to selectively induce different nitrogen functionalities via treatment conditions is key to the design and optimization of such materials. Here, we use density functional theory to study the thermodynamic stability of nitrogen functionalities in three graphene structures as a function of temperature and pressure, providing atomistic insight into the most favorable functionalized configurations. Phase diagrams show that nitrogen incorporation is most exergonic at graphene edges, with pyridinic groups dominating under the majority of conditions studied. For all nitrogen functionalities, lower temperatures and higher pressures result in the greater incorporation of nitrogen into the graphene structures. A density of states analysis shows that the stable pyridinic nitrogen structures induce new electronic states just below the Fermi level whose energy is tunable via nitrogen concentration and hence treatment temperature and pressure. Overall, we have characterized the thermodynamic stability of nitrogen functionalities within graphene and graphene nanoribbons, allowing for the directed tuning of such nitrogen groups experimentally and enabling the construction of more realistic models of nitrogenated graphene structures. Image 1 [ABSTRACT FROM AUTHOR]