Biomass Compounds Research Articles

Enhancing reactive oxygen release-replenishment and Lewis acid acidity by Nb doping in NbmCeOx for simultaneous elimination of NOx and toluene

Multi-pollutant control (MPC) is a promising technology for the simultaneous removal of nitrogen oxidation (NOx) and volatile organic compounds (VOCs) in fossil and biomass fuel combustion. This study uses Nb doping CeO2 bimetallic oxide catalysts to meet low-temperature NH3-SCR de-NOx, catalytic toluene oxidation and simultaneous elimination of NOx and toluene. X-ray diffraction (XRD), Raman and transmission electron microscopy (TEM) are applied to confirm the Nb doping into the lattice of CeO2 for Nb0.034CeOx and Nb0.36CeOx, but excess Nb in polymeric state NbOx present in Nb0.36CeOx. The effects of Nb doping on surface adsorbed oxygen, surface lattice oxygen and bulk phase lattice oxygen were investigated by XPS, EPR, O2-TPD, H2-TPR and DFT calculations. Using in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), it is investigated that the surface reactive oxygen species (including surface adsorbed oxygen and surface lattice oxygen) participates in NO oxidation, NH3 activation and toluene oxidation process. The reaction mechanism of NH3-SCR de-NOx, toluene oxidation and multi-pollutant co-elimination processes, as well as interactions between multiple reactants in the MPC reaction, were also studied with in-situ DRIFTS. It is found that Nb doping contributes to the mobility of lattice oxygen, which favors the oxidation of NH3 to NH2 and the release and rapid replenishment of reactive oxygen species at temperature ≥ 210 °C. The strong Lewis acid sites (Nb5+) promote the adsorption of NH3 species and their stability. These facilitate the NH3-SCR de-NOx in a wide temperature range and achieve the elimination of multiple pollutants on Nb0.034CeOx. So, Nb0.034CeOx exhibits matching activity temperature window in 170–390 °C for MPC (100 ppm toluene and 1000 ppm NO) over 90 % NO and toluene conversion in wet condition. Polymeric NbOx inhibits the activity of surface adsorbed oxygen and surface lattice oxygen and weakens the acidity of Lewis acid, therefore leading Nb0.36CeOx to poor performance of toluene oxidation and NH3-SCR at low-temperature.

Carbon Carriers Driving the Net-Zero Future: The Role of Torrefied Biomass Pellets in Power-To-X

The latest Intergovernmental Panel on Climate Change Sixth Assessment Report urgently calls for sweeping action to mitigate the unprecedented impacts of climate change. The path to a carbon-neutral future is intricate, necessitating a multi-faceted approach that integrates decarbonization, defossilization, and energy/resource efficiency. Power-to-X (PtX) stands as a technological linchpin, converting renewable electricity into a range of sustainable products, from fuels to chemicals. However, its full potential is intrinsically tied to the availability of sustainable carbon sources. This paper evaluates the various avenues for carbon sourcing for PtX: direct air capture (DAC), biogenic carbon, and Long-cycle Industrial Carbon. DAC, although promising for the long term, has limitations in scalability and land requirements. Industrial long-cycle carbon capture technology is improving but requires a thorough Life Cycle Assessment for evaluating its sustainability. This study examines the environmental impacts, scalability, and logistical considerations of each carbon source. Biogenic carbon offers a near-term solution, and its various forms could simplify transportation logistics. An analysis of gasification processes, syngas cleaning, and hydrogen integration was conducted to assess the technical viability of these carbon sources in PtX applications. The results show that torrefied biomass pellets, after a thorough technical assessment, present a globally feasible and sustainable carbon carrier, setting the stage for industry standardization and easier global transportation. Syngas produced through the gasification of the pellets complemented by green hydrogen can be utilized in Fischer–Tropsch, methanol synthesis, and methanation, allowing PtX to synthesize practically any type of organic compounds in a hybrid Biomass–PtX (HBPtX) process. This study provides key insights for industries and policymakers by demonstrating the technical feasibility and sustainability of torrefied biomass as a carbon carrier, thereby supporting the development of comprehensive climate mitigation strategies.

The fate of organic compounds in organic waste during torrefaction and implications for its valorization

Torrefaction is commonly used to improve biomass properties, applications, and economy. The characteristics and subsequent applications of torrefied biomass are largely contingent on the organic compounds in parent biomass and their evolution during torrefaction. Yet, the evolution of organic compounds in biomass particularly minor components (e.g., polyphenols) is far less investigated for torrefaction. To address such issues, a superheated steam (SHS) boosted torrefaction process at different temperatures (200, 250, and 300 °C) and residence times (15, 30, and 60 min) was performed on spent coffee ground (SCG), which is an emerging biowaste and is rich in various organic compounds. Results found that both temperature and residence time determine SHS torrefaction performance. SHS torrefaction could effectively remove volatile matters to upgrade SCG for solid fuel. The relatively high content of N and S in torrefied SCG may negatively affect fuel quality but may benefit its adsorption of environmental pollutants. SHS boosted torrefaction could facilitate cellulose and lipids degradation compared to conventional torrefaction. Efficient reduction/removal of labile carbon and ecotoxic chemicals (e.g., phenols and caffeine) in SCG was successfully achieved with SHS torrefaction. As a result, SHS-torrefied SCG with higher biostability and lower phytotoxicity was evaluated as soil amendments and additives to soilless growing substrate. Implications for subsequent application by revealing the evolution of organic compounds during SHS torrefaction were discussed. This study highlighted the potentiality of SHS torrefaction as a pretreatment of biomass for versatile applications.

Using ethanol and isopropanol as biomass model compounds for understanding bond scission mechanisms over Cu/Mo2N catalysts

The conversion of biomass compounds into fuels and chemicals is an important step towards a more sustainable future. This work combines results from model surfaces and powder catalysts to demonstrate Cu-modified molybdenum nitride (Cu/Mo2N) as a selective catalyst for dehydrogenation of the biomass model compounds, ethanol and isopropanol. Results from model surfaces showed that while Mo2N led to unselective decomposition via both dehydrogenation and dehydration, the addition of Cu increased the dehydrogenation activity and selectivity. DFT calculations showed how Cu influenced the structures of active sites, adsorbate interactions, and thus the product selectivity. Batch reactor studies on corresponding powder catalysts confirmed the trend that Cu modification increased dehydrogenation activity, and in situ X-ray absorption spectroscopy elucidated the Cu oxidation state under reaction conditions. This work demonstrates a strategy for promoting dehydrogenation over Mo2N-based catalysts, as well as the feasibility of using model surfaces to guide the design of industrially relevant catalysts.

Hydrogen production from aqueous‐phase reforming of glycerol, sorbitol, and glycine over Pt/Al2O3catalyst in a fixed‐bed reactor

AbstractAqueous‐phase reforming (APR) is an interesting technique for generating hydrogen (H2) from biofeeds. In this work, APR of model compounds of wet biomass for H2production was investigated. Glycerol, sorbitol, and glycine were the chosen model compounds. They represent polyols and amino acids in wet biomass such as waste sludge and microalgal biomass. The Pt/Al2O3catalyst was preferred and it was characterized using nitrogen adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x‐ray diffraction (XRD), and x‐ray photoelectron spectroscopy (XPS) techniques. APR trials were performed in a continuous fixed‐bed reactor. The reaction conditions chosen for this work were: temperature (T) 453–498 K, pressure (P) 1.2–2.4 MPa, feed concentration 5–15 wt%, and weight hourly space velocity (WHSV) 0.15–0.6 g reactant/(g catalyst h). The best conditions for H2production by the APR process were found to beT = 498 K,P = 2.4 MPa, and feed concentration = 15 wt%. Among the chosen model compounds, glycerol exhibited the highest H2selectivity (82.7%) and H2yield (21.6%) at 498 K. The analysis of kinetic data suggested first‐order reaction kinetics for all the model compounds. The values of activation energy for the reactions with glycerol (55.4 kJ/mol), sorbitol (51.6 kJ/mol), and glycine (45.7 kJ/mol) were determined. Thus, APR is a promising route for effectively producing H2‐bearing gaseous products with high heating value from wet biomass.

Computational investigation of isoeugenol transformations on a platinum cluster—II: Deoxygenation through hydrogenation to propylcyclohexane

The debate on climate change and the future of our Planet has brought to general attention the problem of fossil fuels (coal, oil and natural gas), among the main causes of pollution on Earth. At the same time, the necessity to encourage research and development of alternative and renewable energy resources has become increasingly relevant. In this context, biomass is an attractive option to produce biofuels and chemicals currently derived from petroleum. The hydrodeoxygenation process of bio-oils, produced by the rapid pyrolysis of biomass, is the most effective strategy for obtaining biofuels, hence the reason for the investigation of its mechanism on model biomass compounds. Having investigated the direct deoxygenation (DDO) mechanims in the first paper of this series, the present work aims to illustrate the deoxygenation-through-hydrogenation (HYD) mechanism, by which isoeugenol, a compound chosen as a model of bio-oils, is converted into propylcyclohexane on a ten-atom platinum cluster. DFT calculations highlight, from kinetic and thermodynamic perspectives, how the formation of propylcyclohexane takes place through 4-propyl-2-methoxycyclohexane-1-ol, the removal of –OCH3 as methanol and then of the –OH group as water. Microkinetic analysis, performed by joining findings on both DDO and HYD routes, reveals that the isoeugenol DDO mechanism is favored at any selected temperatures.

Effect of lignin, cellulose and hemicellulose from biomass on sulfur release behavior from dyeing sludge combustion

Co-combustion with biomass is recommended for treating dyeing sludge (DS) from the view of minimizing sulfur emissions. However, the sulfur emission from DS combustion depends on the lignin (L)/cellulose (C)/hemicellulose (H) ratio in the biomass, which is frequently overlooked. This study reveals the effect of biomass on the combustion characteristics and sulfur evolutions of DS combustion using triphenylmethyl mercaptan (TM) and L/C/H as model representative compounds of DS and biomass, respectively. Results indicated that the combustion behavior of the TM–biomass mixture was dominated by TM and secondarily by L/C/H. Although L/C/H brought forward the TM combustion, these biomass components (especially L) deteriorated the combustibility and burnout performances of the combustion. L/C/H promoted CH3SH and SO2 release at low temperatures but inhibited these emissions at high temperatures. The sulfur retention ratios of L, C, and H were 7.53 %, −5.75 %, and 0.17 %. TM–L interaction initially promoted and later inhibited the co-combustion process and the CH3SH and SO2 release. L/C/H addition reduced the E values of the mixtures and the co-combustion kinetics were dominated by Dn models. Residue analysis also indicated a dominant role of L in sulfur fixation, mainly because L additive created abundant adsorption sites in the co-combustion residue.

Surface assisted laser desorption/ionization mass spectrometry of lithium cationized lignans – A tool for rapid screening of plant extracts

Lignans are one of the most widespread classes of plant secondary metabolites possessing unique biological activities. The search for new sources of such compounds, their screening and identification in plant biomass is an urgent task, requiring the use of advanced analytical methods. In the present study, matrix-free surface assisted laser desorption/ionization (SALDI) mass spectrometry was proposed for its solution. The combination of carbon nanocoating sputtered on a target plate with lithium cationization allowed obtaining high-quality mass spectra of eight coniferous wood lignans with different bonds between aromatic units (secoisolariciresinol, matairesinol, 7-hydroxymatairesinol, nortrachelogenin, pinoresinol, guaiacylglycerol-β-guaiacyl ether, dehydrodihydrodiisoeugenol, and divanillin). Three types of fragmentation methods (post-source decay, high- and low-energy collision induced dissociation) for the first time were implemented on two types of MALDI instruments. Regardless of tandem mass spectrometry technique, lignans demonstrated the similar fragmentation patterns including the cleavage of bonds between aromatic units with the formation of mostly lithiated product ions. The low-energy collision induced dissociation in quadrupole ion trap provided the most informative tandem mass spectra and multi-stage fragmentation capabilities in structural studies. On this basis, an approach to rapid, high-throughput, and low-cost screening and tentative identification of lignans including isomeric compounds in plant biomass was developed and successfully tested on real samples of pine, fir, spruce, and larch knotwood extracts.

IADOR yields diverse shape-selective solid Lewis acid catalysts

Lewis acid catalysts convert biomass compounds to green chemicals and fuels. Among these catalysts, stannosilicate zeolites display high thermal stability and reusability. However, only a few Sn-zeolites can be prepared using conventional synthesis methods, preventing us from developing shape-selective stannosilicate catalysts. Here, we propose a synthetic approach toward shape-selective Sn-zeolite catalysts, leveraging the Assembly, Disassembly, Organization, Reassembly (ADOR) strategy. By combining isomorphous Sn incorporation (i) into germanosilicate zeolites UOV, IWW, and IWR in the A step with structural modification in the DOR steps, we targeted new Sn-zeolite structures with either parallel or intersecting 12- and 8-ring pores predominantly containing Lewis acid centers with hydrolyzed Sn-O-Si bonds. The shape-selective performance of the designed Sn-zeolite catalysts was experimentally assessed and theoretically rationalized in transformations of citronellal into citronellol by Meerwein-Ponndorf-Verley reduction and into isopulegol isomers via intramolecular cyclization. Therefore, iADOR paves the way toward new zeolite catalysts with engineered Sn active sites for green chemistry.

Continuous-flow hydrogenation of cinnamaldehyde over catalysts derived from modified CoAl4 layered double hydroxides incorporating Mn, Ni, Cu and Zn ions

Series of CoxM1-xAl4 layered triple hydroxides, LTHs were prepared as catalyst precursors for hydrogenation of biomass compound cinnamaldehyde under flow and batch reaction conditions. To this end, we have successfully extended the eco-friendly family of Al-rich layered double hydroxides (LDHs) by synthesizing MnAl4-LDHs, furthermore Co3Al-, Co2Al-LDHs were also exploited. Both the magnetic Co-rich and Al-rich reduced forms behaved as robust, efficient and reusable catalysts with significantly different selectivities correlated with their acid-base properties. Al-rich solids showed increased acidity and lower basicity resulting in high hydrocinnamaldehyde selectivity (∼75 %), while the Co-rich catalysts attested enhanced hydrocinnamyl alcohol production (∼80 % selectivity) due to their low acidity and high basicity (mapped by NH3/CO2 temperature programmed desorption tests). Incorporation of Mn, Ni, Cu and Zn ions generally decreased the total acidity of Al-rich catalysts, while their Lewis basicity largely increased: the highest was found for Mn, resulting in activity similar to that of Co-rich catalysts.

Long-term stability of cellulose membranes in spent deep eutectic solvent used in the recovery of lignin from lignocellulosic biomass

Deep eutectic solvents (DESs) are a novel class of solvents that can be used to fractionate biomass compounds. However, their sustainability depends strongly on their recyclability. In previous research, it was seen that membrane filtration with commercial cellulose membranes (RC70PP and Ultracel 5 kDa) might be a solution for purification of spent deep eutectic solvent (DES) that has been used in lignin extraction (Choline Chloride: Lactic Acid 1:10 molar ratio) from woody biomass. This DES is, however, very acidic (pH 1.3), which can have detrimental effects on the longevity of the membrane. In a previous study, the time that the membranes were exposed to the spent DES was relatively short. This study aims to increase knowledge of how cellulose membranes withstand spent DES over longer time periods of up to 8 weeks. The results show that cellulose membranes are quite stable under exposure to spent DES in terms of pure water flux and PEG retention for up to 4 weeks. After 8 weeks, the RC70PP membrane demonstrated an increase in pure water permeability of 45% and a noticeable decrease in PEG retention. Surface characterization revealed, however, that the chemical structure of the cellulose membranes changed already after 2 weeks of exposure prior to any changes in pure water permeability were observed. Experimentally revealed esterification of cellulose membrane by Lactic Acid of DES led to more negative charge of the exposed samples compared to their references. This esterification was accompanied by hydrolysis that removed amorphous parts and increased the crystallinity of the membrane.

Alteration of biomass toxicity in torrefaction – A XDS-CALUX bioassay study

Torrefaction constitutes one of the promising technologies for the management of waste biomass and the production of high-carbon products for combustion, gasification, adsorption of pollutants or soil treatment. Unfortunately, waste biomass may be contaminated with toxic persistent organic pollutants, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF) and dioxin-like biphenyls (dl-PCB). Literature does not provide consistent measurements on how the low-temperature thermochemical processing, such as torrefaction, affects the toxicity of biomass. This contribution assesses how a torrefaction treatment, conducted at 200 °C, modifies the toxicity due to PCDD/PCDF/dl-PCB in biomass. We deploy the XDS-CALUX biotest on five types of waste biomass (sewage sludge, tree bark, cattle manure, spent coffee ground, common reed), before and after treatment. The content of total dioxin- & biphenyl fraction compounds in the raw biomass, investigated in this study, varies from 0.14 to 3.67 pg BEQ·g−1d.m., and in the torrefied biomass between 0.17 and 6.00 pg BEQ·g−1d.m.; BEQ stands for bioanalytical equivalent. This increase is statistically insignificant at p = 0.05, taking into account all types of examined biomass. This proves that low-temperature torrefaction cannot detoxify biomass, i.e., chars, produced from biomass characterized by elevated concentration of PCDD/PCDF/dl-PCB, will reflect the contamination of the feedstocks. With respect to heavy metals, we conclude that only the content of Cd in biomass, and, to a lesser extent, the abundance of Cu and Fe, modify the toxicity of this material during its thermochemical treatment at low temperature.

Kraft and organosolv lignin-activated carbon composites for supercapacitor electrode materials

Lignin-activated carbon (AC) composites were employed as electrode active materials to develop more environmentally friendly Supercapacitor (SC) materials with enhanced properties. This way, the hydroquinone/quinone moieties present in lignin molecules added Faradaic processes to the system, and the capacitance of the active material increased, making it appropriate for future applications requiring more efficient and sustainable active materials. Lignin, a sustainable biobased aromatic polymer high in carbon content, was deposited on AC surface employing ultrasound (US) system, and for a better deposition, AC was treated with HNO3. Since the composition and properties of lignin can vary depending on their isolation process, two different types of lignin were used: Kraft lignin (KL) and Organosolv lignin (OL), and the effects on the chemical and electrochemical composition were deduced. Physicochemical, morphological, and electrochemical analyses were carried out on the lignin-AC composite to determine the optimum material combination and treatment process. It was observed that the acid treatment was effective in enhancing the functionality and porosity of the surface. Additionally, it improved the deposition of lignin and facilitated the formation of hierarchically porous structures on the surface of treated activated carbon (TAC), with different tendencies depending on the lignin employed. The creation of highly porous structures also resulted in enhanced electrochemical performance in materials. This validated the process, where eco-innovative technologies like US forces and employment of lignocellulosic biomass compounds like lignin were used as sustainable and efficient alternatives for obtaining electrochemically active materials.

Off-odour Identification from Volatile Organic Compounds (VOCs) of Spirulina

Spirulina platensis is a common cyanobacteria microalga with high nutrition and bioactive compound sources. The addition of spirulina in foods and beverages improves nutrition and bioactive compound content. However, certain species of cyanobacteria are known to produce various compounds causing off-odour. This study investigates the chemical profile and volatile organic compounds (VOCs) in spirulina biomass and determine off-odour potency. The spirulina extract was analysed phytochemical qualitatively and GC-MS (Gas Chromatography-Mass Spectrometry). The Spectra mass was compared to the mass spectral database and profile of chemical compound libraries. The result shows, phytochemical analysis positively contains of alkaloids, flavonoids, tannins, saponins, and terpenoids. A total of 155 volatile compounds consisting of classes acid, alcohol, aldehyde, alkene, benzene, ether, ester, ketone, sulphur-contain, and terpene were identified. The off-odour VOC content such as phytol; cyclopropanebutanoic acid, 2- [[2 - [[2 - [(2- pentylcyclopropyl) methyl) cyclopropyl) methyl) cyclopropyl) methyl]-, methyl ester; 3.7.11.15-tetramethyl-2-hexadecen-1-ol; Imidazole, 2-fluoro-5-(2-carboxyvinyl)-; β-ionone; and N,N-Dimethyl-O-(1-methyl-butyl)-hydroxylamine, were detected in spirulina. The odour descriptions of off-odour VOCs are floral, balsamic, powdery, waxy, rancid, sweaty, woody, alkali, and fish-like. The off-odour content of VOCs might influence food's sensory odour, with spirulina added in excessive quantities.

Combination of chemometrics and mass spectrometric methods for the data mining of molecular structure information of coal and biomass

The combination of mass spectrometry (MS) data and chemometrics methods is conducive to obtaining more comprehensive molecular information and evaluating the transfer behavior of O and N atoms during the conversion of biomass and coal. In this work, 12 thermal dissolution (TD) extracts of coal/biomass samples and the catalytic hydrogenation products of TD extracts were analyzed by Orbitrap MS using spectral stitching and in-source collision-activated dissociation (ISCAD) methods. Spectral stitching improves the detection ability towards minor and trace species, enhancing the number of identified compounds by two times. Meanwhile, ISCAD provides more comprehensive molecular structure information, which can illustrate the transfer patterns of heteroatoms and deepen the understanding of the structural characteristics of aromatic rings during the conversion of biomass and coal. Two chemometrics methods, principal component analysis (PCA) and hierarchical cluster analysis (HCA), were introduced to dig out the detailed similarities and differences between O-containing and N-containing compounds in coal and biomass. HCA method not only recognized the category of O-containing and N-containing compounds in each sample, but also showed the removal behavior of O and N atoms in biomass and coal. Thus, the combination of MS methods and chemometrics method is expected to provide methodological support to elucidate the molecular structure and conversion pathways for complex coal and biomass.

Reaction characteristics of homogeneous and heterogenous reactions for glucose gasification in supercritical water using ruthenium catalyst supported on carbon nanotube

In this study, a spherical, Ru-based catalyst with a Carbon nanotube (CNT) support was used in a continuous-flow system, where homogeneous and heterogeneous reactions occurred simultaneously. Therefore, determining the homogeneous and heterogeneous reaction rates is important. Glucose (5 and 10) wt%, a typical model biomass compound, was chosen as the feedstock, and the reaction temperature was set at (500 and 600) ℃. The weight hourly space velocity was changed (40, 80, or 160) h−1 by maintaining the catalyst loading at 0.15 g and altering the flow rate (2, 4, or 8) mL/min. A reaction model where homogeneous and heterogeneous reactions proceed in parallel was developed, and the reaction rates were determined. The homogeneous reaction rate constants were (0.00968 and 0.0194) /s for (500 and 600) ℃, respectively, and the heterogeneous ones for Ru-based catalyst with a CNT support were (0.0137 and 0.0420) m3/(kg s) for (500 and 600) ℃, respectively.

Aqueous‐phase reforming of model compounds of wet biomass to hydrogen on alumina‐supported metal catalysts

AbstractCatalytic aqueous‐phase reforming (APR) of wet biomass such as microalgae and activated sludge is a potential technique for the production of H2‐rich gaseous products. In the present work, model compounds such as ethylene glycol, xylose and alanine were selected as representatives of the polyols, carbohydrates and proteins in wet biomass. APR trials were performed in a stirred batch reactor using commercial Pt/Al2O3 and Ru/Al2O3 catalysts. The reforming reactions were investigated at different conditions: temperature (T), 498 to 518 K, feed concentration, 1 to 5 wt. %, catalyst loading (ω), 2 to 6 kg/m3, and reaction time (t), 1 to 6 h. The commercial Pt/Al2O3 catalyst exhibited higher reforming activity. The influence of reaction parameters on turnover frequency (TOFH₂), hydrogen yield (Y‐H2) and carbon‐to‐gas conversion (C to G conversion) was studied. The values of TOFH₂ for Pt/Al2O3 were measured at T = 518 K, ω = 2 kg/m3 and t = 3 h using 1 wt% feed and these values were 19.2, 4 and 6 1/min for ethylene glycol, xylose and alanine. The values of TOFH₂ over Ru/Al2O3 under identical conditions were: ethylene glycol–12.4, xylose–1.4 and alanine–5.4 1/min. The activation energies for H2 production from ethylene glycol, xylose and alanine over Pt/Al2O3 and Ru/Al2O3 catalysts were determined. APR of the mixture of model compounds was also studied over laboratory‐made Pt/Al2O3 and Ru/Al2O3 catalysts at the optimum reaction conditions. Thus, this work has provided crucial insights into the production of H2 from model compounds of wet biomass using Al2O3‐supported catalysts.

Production of carotenoids from aromatics and pretreated lignocellulosic biomass by Novosphingobium aromaticivorans.

There is economic and environmental interest in generating commodity chemicals from renewable resources, such as lignocellulosic biomass, that can substitute for chemicals derived from fossil fuels. The bacterium Novosphingobium aromaticivorans is a promising microbial platform for producing commodity chemicals from lignocellulosic biomass because it can produce these from compounds in pretreated lignocellulosic biomass, which many industrial microbial catalysts cannot metabolize. Here, we show that N. aromaticivorans can be engineered to produce several valuable carotenoids. We also show that engineered N. aromaticivorans strains can produce these lipophilic chemicals concurrently with the extracellular commodity chemical 2-pyrone-4,6-dicarboxylic acid when grown in a complex liquor obtained from alkaline pretreated lignocellulosic biomass. Concurrent microbial production of valuable intra- and extracellular products can increase the economic value generated from the conversion of lignocellulosic biomass-derived compounds into commodity chemicals and facilitate the separation of water- and membrane-soluble products.

Aqueous phase reforming of various compounds in biomass derived products over Ni/α-MoO3 catalysts: Effect of alkali and alkaline earth metals

Aqueous phase reforming (APR) of biomass derived products is a promising hydrogen generation approach, and many internal alkali and alkaline earth metals (AAEMs) have been proven capable of catalyzing these processes. In this study, APR of various functional groups in biomass derived products over Ni/α-MoO3 catalyst toward hydrogen production and pollutants control was investigated. The effect of different AAEMs was comprehensively studied under a temperature of 225 °C and a residence time of 30 min. Findings demonstrated that Na, K, Ca, and Mg all showed hydrogen generation and total organic carbon removal capability, whose performances were competitive to Ni/α-MoO3 catalyst. Moreover, although the presence of single K suppressed the removal of total nitrogen (TN), the combination of K and the Ni/α-MoO3 catalyst exhibited the optimal removal efficiency of TN (69.92 %). A series of characterization results revealed that the AAEMs effectively prevented Ni leaching in the hydrothermal environment of the Ni/α-MoO3 catalysts and promoted the formation of oxygen vacancies, inhibiting carbon deposition and deactivation of the catalyst.

Selection of the Second Adsorbent for Sampling Volatile Organic Compounds in the Biomass Gasification Tar Using Solid-Phase Adsorption.

The purpose of this study is to examine the effectiveness of a solid-phase adsorption method for measuring the concentrations of tar compounds in biomass. This method involves collecting tars on a column with an amino-phase sorbent. However, because biomass tar has a high concentration of volatile organic compounds, not all of them can be collected with just one column. Therefore, the researchers decided to add a second column with a different adsorbent to improve the accuracy of the measurement. They also chose to test three different sorbents (Carbopack B, Carbotrap, and activated coconut charcoal) in order to determine which one is the most effective for determining the concentration of volatile organic compounds. The desorption efficiency from various sorbents, the adsorption efficiency of the studied compounds on each sorbent depending on the sampled gas temperature, and the maximal amounts of compounds adsorbed on activated coconut charcoal were evaluated. The best results were obtained using activated coconut charcoal. A modified sampling device consisting of 500 mg of the amino-phase adsorbent and 100 mg of activated coconut charcoal was selected as the optimal choice for collecting tar, including its volatile organic compounds, from the synthesis gas generated during biomass gasification.