Cellulose Degradation Products Research Articles

Production of Glucose from Waste Bark Acacia Mangium Using Delifnification and Chemical Hydrolysis Process

The bark of Acacia mangium is lignocellulosic biomass from waste pulp which can be recovered by means of hydrolyse to produce simple sugar called glucose. To produce glucose, there are two stages of the process performed is process using solvent delignification NaOH and KOH. The parameters analyzed were the biomass with a solvent ratio (1:6, 1:8, 1:10, 1:12). The second stage cellulose is then hydrolyzed to see the influence of sulfuric acid concentration of the resulting glucose content (0.1; 0.25; 0.40; 0.55% (v/v)).Lignin removal efficiency using NaOH and KOH solvent that is almost equal to 62.39%. Decrease hemicellulose using KOH solvent (36%) are more efficient than solvent only 29.3% NaOH. Efficiency increased levels of cellulose using NaOH or KOH solvent almost equal approximately 85.5%, but with KOH the lower alkaline properties provide a more stable rise. Solvent delignification process with NaOH provide large enough glucose content at a ratio of 1: 6 and 1: 8 with sulfuric acid concentration in the range of 0.1 to 0.4 and 0.5% v/v. Increased glucose content in the solvent of NaOH at a ratio of 1:6 reached 69.88 ppm for sulfuric acid concentration of 0.55% v/v, whereas the content of glucose degradation products of cellulose with delignification process using KOH solvent is in the range of 3.25 ppm to 77.67 ppm. The highest value is produced by the hydrolysis of cellulose to the sulfuric acid concentration of 0.4% v/v, and the KOH solvent ratio is 1:10. The higher the ratio, the lower the KOH solvent content of glucose produced.

Brønsted acidic ionic liquid catalyzed one-pot conversion of cellulose to furanic biocrude and identification of the products using LC-MS

The degradation of cellulose was studied using 1-(3-propylsulfonic)-3-methylimidazolium chloride and 1-(4-butylsulfonic)-3-methylimidazolium chloride acidic ionic liquids as catalysts in acetone at 120 °C for 3.5 h. The products were analyzed using LC-MS with a C18 column and 0.1% formic acid in water - methanol as the eluent solvent. Eleven cellulose degradation products were identified in the furanic biocrude formed using mass spectroscopy. The identified compounds include: 5-hydroxymethylfurfural (HMF), seven products formed from aldol condensation of HMF with one to three acetone molecules, one furfural-acetone aldol product and two HMF ether products. The percent conversions of cellulose to the furanic biocrude product for the two catalysts 1-(3-proylsulfonic)-3-methylimidazolium chloride and 1-(4-butylsulfonic)-3-methylimidazolium chloride were 25.7 and 19.3% respectively.

Influence of step duration in fractionated Py-GC/MS of lignocellulosic biomass

Fractionated pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS) appears as an interesting analytical tool for elucidating lignocellulosic biomass structure, as it allows the progressive release of chemical fragments representative of biomass macromolecular composition. In this paper the effect of fractionated pyrolysis time (from 5 s to 300 s) on the degradation of lignin and carbohydrates from beech wood was studied at temperatures between 250 °C and 500 °C. Fractionated Py-GC/MS showed that the release temperature of the volatile degradation products varied between the volatile species detected. In addition, the step duration time changed the thermal degradation behavior of lignocellulosic components. Shortening the constant step duration time from 300 s to 5 s shifted the maximum weight loss to the higher temperatures. The result was opposite at long step duration times. Time optimization at each pyrolysis temperature (250 °C, 40 s; 300 °C, 30 s; 350 °C, 25 s; 370 °C, 20 s; 400 °C, 15 s; 450 °C, 10 s; 500 °C, 5 s) enhanced the yield of both lignin and carbohydrate volatile pyrolysis degradation products. In addition, two multiple temperature maxima were shown for some lignin and carbohydrate derivatives. This behavior may be due to the two different pathways of formation and macromolecular origins of compounds in beech wood. At optimized conditions lignin derivatives having a 3-carbon side chain substituent had a maximum at lower temperature than that of lignin derivatives with a 1-carbon side chain substituent. That phenomenon follows the order of primary and secondary pyrolysis reactions. Similar behaviors were observed among the degradation products of hemicelluloses and cellulose. Degradation products of hemicelluloses were mainly released at lower temperatures than those of cellulose derivatives, which illustrates the lower thermal stability of hemicelluloses compared to cellulose.

Restoring Waning Production of Volatile Organic Compounds in the Endophytic Fungus Hypoxylon sp. (BS15).

Certain endophytic fungi belonging to the Hypoxylon genus have recently been found to produce volatile organic compounds (VOCs) that have potential relevance as hydrocarbon fuels. Here, a recently discovered Hypoxylon sp. (BS15) was demonstrated to also produce VOCs, but with diminished VOC production after an extended period of in vitro growth. Restoring VOC production was partially achieved by growing BS15 in growth media containing finely ground woody tissue from the original host plant (Taxodium distichum). In an effort to isolate VOC production modulators, extracts from this woody tissue were made by sequentially extracting with dichloromethane, methanol, and water. Both the dichloromethane and water extracts were found to modulate VOC production, while the methanol extract had no effect. Surprisingly, the woody tissue remaining after exhaustive extraction was also shown to act as a VOC production modulator when included in the growth media, with changes observed in the production of four compounds. This woody tissue also induced production of two compounds not observed in the original BS15 extract. Filter paper had the same modulating effect as exhaustively extracted woody tissue, suggesting the modulation was perhaps due to cellulose degradation products. Overall, this study demonstrated that VOC production in BS15 can be influenced by multiple compounds in the woody tissue rather than a single modulator.

Carbon-dependent chromate toxicity mechanism in an environmental Arthrobacter isolate

Arthrobacter spp. are widespread in soil systems and well-known for their Cr(VI) reduction capabilities making them attractive candidates for in situ bioremediation efforts. Cellulose drives carbon flow in soil systems; yet, most laboratory studies evaluate Arthrobacter-Cr(VI) interactions solely with nutrient-rich media or glucose. This study aims to determine how various cellulose degradation products and biostimulation substrates influence Cr(VI) toxicity, reduction, and microbial growth of an environmental Arthrobacter sp. isolate. Laboratory culture-based studies suggest there is a carbon-dependent Cr(VI) toxicity mechanism that affects subsequent Cr(VI) reduction by strain LLW01. Strain LLW01 could only grow in the presence of, and reduce, 50 μM Cr(VI) when glucose or lactate were provided. Compared to lactate, Cr(VI) was at least 30-fold and 10-fold more toxic when ethanol or butyrate was the sole carbon source, respectively. The addition of sulfate mitigated toxicity somewhat, but had no effect on the extent of Cr(VI) reduction. Cell viability studies indicated that a small fraction of cells were viable after 8 days suggesting cell growth and subsequent Cr(VI) reduction may resume. These results suggest when designing bioremediation strategies with Arthrobacter spp. such as strain LLW01, carbon sources such as glucose and lactate should be considered over ethanol and butyrate.

Thermodynamic description of the plutonium – α-d-isosaccharinic acid system I: Solubility, complexation and redox behavior

The impact of α-d-isosaccharinic acid (HISA), a degradation product of cellulose, on the solubility and redox behavior of hydrous Pu(IV) oxide was investigated from undersaturation conditions under Ar atmosphere in 0.1 m NaCl–NaOH–NaISA solutions. Redox conditions were buffered with hydroquinone (HQ) or Sn(II), resulting in (pe + pHm) ≈ 9.0 and 1.5, respectively. The influence of ISA on Pu solubility was investigated as function of pHm (8 ≤ pHm ≤ 13) and ligand concentration (10−6 m ≤ m(ISA)tot ≤ 0.1 m).In-situ X-ray diffraction and X-ray absorption spectroscopic measurements indicate that PuO2(ncr,hyd) controls the solubility of Pu in all investigated systems. Presence of ISA poses an increase in plutonium solubility by up to 2.5 log-units. In HQ systems, slope analysis of solubility data in combination with solid phase characterization and density functional theory calculations resulted in chemical and thermodynamic models including the predominance of Pu(IV)(OH)3ISA–H– and Pu(IV)(OH)3ISA–2H2– complexes below and above pHm ≈ 12, respectively. In Sn(II) systems with pHm < 11.5, a reductive dissolution occurs involving the formation of Pu(III)(OH)ISA–H(aq). Experimental observations suggest also that Pu–ISA colloids importantly contribute to the overall Pu concentration in solution, both in HQ and Sn(II) systems. Although this process is not included in the thermodynamic model derived, it cannot be neglected for estimating Pu solubility limits under these conditions. This work provides the most comprehensive thermodynamic dataset available to date for the system Pu3+–Pu4+–OH––Cl––ISA––H2O(l) valid under a wide range of conditions relevant for nuclear waste disposal.

Sugar is a sign of smoldering biomass fires

Levoglucosan, an anhydrous sugar formed as a cellulose degradation product, has been used for nearly two decades as an atmospheric aerosol marker of wood burning. At the meeting, Hafiz Abdul Azeem and coworkers at Lund University reported that it could also be a marker for smoldering fires in stored dry biomass for use in energy production. A low-temperature fire inside a stack of biomass can smolder for days, weeks, or even longer without producing flames and thus escape detection. To determine whether levoglucosan can be detected from smoldering fires, the researchers packed cotton into a concrete block and triggered smoldering with heating wires. They collected aerosol particles on quartz filters at approximately 30-minute intervals. They extracted and analyzed the particles by gas chromatography-mass spectrometry. They kept data from only those experiments in which the cotton started blackening within three hours and in which the stack went into flames after eight

Interdisciplinary approach to develop a disposable real time monitoring tool for the cleaning of graphic artworks. Application on “le Nozze di Psiche”

Disposable non-invasive and compatible real time monitoring tool was developed in order to follow the cleaning process of paper artwork directly in situ. This tool was based on a biocompatible cleaning hydrogel coupled with flow electrochemical diagnostic tool, suitable to verify in situ and in a simple way the assessment of degradation of artwork and the efficiency of cleaning process. In this paper, the results obtained by applying this tool on a great format artwork with a lining as support, “Le Nozze di Psiche”, engraved by Diana Scultori, printed in 1613, are reported. This opera was affected by a structural and chromatic deterioration due to a strong oxidative degradation. Such deterioration was probably accelerated by the adhesive (a mixture of starch paste and animal glue) used in a previous lining intervention. In this case, the cleaning agents used are rigid hydrogels of Gellan gum, modified with hydrolytic enzymes. By using the flow sampling system, all materials removed by the gel was carried up to a thin layer cell containing a selective electrochemical biosensors, suitable to monitor both treatments, the cleaning process and the removal of lining. These were monitored, allowing understanding when both processes were completed, thus avoiding lengthy and unnecessary cleaning applications. The effectiveness of cleaning with Gellan gel was assessed quantitatively by using non-invasive optical reflectance spectroscopy by a portable instrumentation, elaborating data with an improved version of the Kubelka-Munk theory in order to recover the absorption coefficient of the cellulose fibers of “Le Nozze di Psiche”. The concentration of oxidized groups acting as chromophores was obtained by comparing the experimental optical absorption spectra to those simulated computationally by using TDDFT-based calculations. By following the cleaning with Gellan gel the results indicate a large decrease of the concentration of degradation product of cellulose. Moreover, chromatographic analysis were carried out in order to evaluate the amount of acid compound, produced during the aging and present on the graphic artwork, using the Gellan gel after cleaning step. The results obtained from the restoration of “Le Nozze di Psiche” have allowed the restorers to evaluate innovative methods for cleaning treatment of paper artworks with a highly specialized scientific-diagnostic approach.

The biogeochemistry of gas generation from low-level nuclear waste: Modelling after 18 years study under in situ conditions

Gas generation from low- and intermediate-level nuclear waste (LILW) is an important process related to the safety of near surface and geological nuclear waste repositories. Generation of a gas phase has the potential to transport gaseous radionuclides such as 14C to the biosphere. Furthermore, pressurisation and gas phase formation can affect the engineered barrier system and water flow, which can affect the transport of radionuclides and other soluble contaminants in water. Microbial gas generation is coupled with a wider range of biogeochemical processes that are also relevant to the safety of LILW repositories through effects on pH, Eh and organic complexation. The large scale Gas Generation Experiment (GGE), located at the VLJ repository, Olkiluoto, Finland has been in operation for 18 years to study processes of gas generation from cellulose-containing low-level waste (LLW) from the Olkiluoto power plants. Here we provide an update of the experiment data set that records, over a period of 18 years, the neutralisation of the initial pH 10–11 conditions in the water filled regions of the experiment that were buffered by a concrete container, of relatively small mass, by acidity generated by degradation of cellulose LLW materials. The neutralisation of pH below pH 9 coincides with a doubling of the generation rate of a CH4-rich gas to around 1 m3 per year. Aqueous sulfide is also present at low levels (<3 × 10−6 M) at this time, consistent with equilibrium with mackinawite (FeS). Dissolved organic carbon attained a peak concentration of 8 mM during the early stages of the experiment, prior to the higher gas generation rate, but after 9 years declined. After 18 years the Eh of the tank water measured by a Pt electrode is consistent with that calculated for the S(-2)/S(6) and methanogenesis redox couples suggesting equilibration of redox processes. Carbonate concentration has increased steadily to around 15 mM. After 7 years CO2 gas and aqueous and solid carbonates are also close to equilibrium. The experimental data has been interpreted with the aid of a biogeochemical model that represents the coupled processes of organic waste degradation, pH buffering and microbial gas generation. The model simulates that the majority of the gas is generated by H2 and organic consuming methanogenic processes in the waste drums. The increase in CH4 generation is simulated to be the result of methanogenic processes that consume soluble cellulose degradation products that diffuse into the tank water from the waste drums. It is expected that under the steady state conditions now established, resulting from gas/liquid/solid equilibrium and diffusion processes, that gas generation should continue until the cellulose and steel materials are exhausted. The experimental data and biogeochemical model can be used to predict the rate of CH4-rich gas generation from the VLJ and other repositories with higher proportions of cementitious materials. In addition the study has shed further light on the role of microbial processes in affecting pH buffering of cementitious conditioned LILW.

Thermodynamic model of Ni(II) solubility, hydrolysis and complex formation with ISA

AbstractThe solubility of β–Ni(OH)2(cr) was investigated atT=(22±2)°C in the absence and presence of α-isosaccharinic acid (ISA), the main degradation product of cellulose under alkaline pH conditions. Batch solubility experiments were performed from undersaturation conditions under inert gas (Ar) atmosphere. Solubility experiments in the absence of ISA were conducted in 0.5 and 3.0 M NaCl–NaOH solutions at 7.5≤ pHm≤13 (with pHm=–log10[H+]). XRD analyses of selected solid phases collected after completing the solubility experiments (≈300 days) confirmed that β–Ni(OH)2(cr) remains as solid phase controlling the solubility of Ni(II) in all investigated conditions. Based on the slope analysis (log10[Ni] vs. pHm) of the solubility data and solid phase characterization, the equilibrium reactions β–Ni(OH)2(cr)+2 H+⇔Ni2++2 H2O(l) and β–Ni(OH)2(cr)⇔Ni(OH)2(aq) were identified as controlling the solubility of Ni(II) within the investigated pHmregion. The conditional equilibrium constants determined from the solubility experiments at different ionic strengths were evaluated with the specific ion interaction theory (SIT). In contrast to the current thermodynamic selection in the NEA–TDB, solubility data collected in the present work does not support the formation of the anionic hydrolysis species Ni(OH)3−up to pHm≤13.0. Solubility experiments in the presence of ISA were conducted in 0.5 M NaCl–NaOH–NaISA solutions with 0.01 M≤[NaISA] ≤0.2 M and 9≤ pHm≤13. XRD analyses confirmed that β–Ni(OH)2(cr) is also the solid phase controlling the solubility of Ni(II) in the presence of ISA. Solubility data of all investigated systems can be properly explained with chemical and thermodynamic models including the formation of the complexes NiOHISA(aq), Ni(OH)2ISA−and Ni(OH)3ISA2−. The reported data confirm the low solubility (&lt;10−7M) of Ni(II) in hyperalkaline pH conditions representative of cementitious environments (10≤ pH ≤13), which increases to up to 10−5M in the presence of 0.2 M NaISA. These results significantly improve source term estimations for Ni(II) in environments relevant for the disposal of low and intermediate level radioactive waste (L/ILW). The chemical and thermodynamic models derived in this work can be implemented in geochemical models/calculations, and provide further confidence in the safety analysis of repositories for the disposal of L/ILW.

Effects of cellulose degradation products on the mobility of Eu(III) in repositories for low and intermediate level radioactive waste

The deep repository for low and intermediate level radioactive waste SFR in Sweden will contain large amounts of cellulosic waste materials contaminated with radionuclides. Over time the repository will be filled with water and alkaline conditions will prevail. In the present study degradation of cellulosic materials and the ability of cellulosic degradation products to solubilize and thereby mobilise Eu(III) under repository conditions has been investigated. Further, the possible immobilization of Eu(III) by sorption onto cement in the presence of degradation products has been investigated. The cellulosic material has been degraded under anaerobic and aerobic conditions in alkaline media (pH: 12.5) at ambient temperature. The degradation was followed by measuring the total organic carbon (TOC) content in the aqueous phase as a function of time. After 173days of degradation the TOC content is highest in the anaerobic artificial cement pore water (1547mg/L). The degradation products are capable of solubilising Eu(III) and the total europium concentration in the aqueous phase was 900μmol/L after 498h contact time under anaerobic conditions. Further it is shown that Eu(III) is adsorbed to the hydrated cement to a low extent (<9μmol Eu/g of cement) in the presence of degradation products.

Age and Origin of the Well-Preserved Organic Matter in Internal Sediments from the Silesian-Cracow Lead-Zinc Deposits, Southern Poland

The molecular and petrographic characteristics of organic matter in internal sediments from the Mississippi Valley-type lead-zinc deposits in southern Poland reveal immature and well-preserved organic matter. Huminite reflectance values of organic matter in all internal sediments are low, with a mean value of 0.29%, corresponding to a lignite range of coalification. Most organic compounds in the organic matter (e.g., cadalene, retene, simonellite, perylene, and β -sitosterol and its transformation products stigmastanol and stigmasta-3,5-dien-one), as well as lignin degradation compound products (e.g., benzoic acid, vanillin, 4-benzaldehyde, benzenedicarboxilic acids, and hydroxybenzoic acids), are of terrestrial origin. Monosaccharides with dominant α - and β -glucose were identified as possible remnants of cellulose degradation products, suggesting an excellent state of organic matter preservation, given that monosaccharides are preserved only under conditions of limited oxygen after sedimentation, resulting from the rapid accumulation of internal sediments in meteoric paleokarst cavities followed by insignificant diagenesis. Petrologic and palynological data on internal sediments clearly indicate a Middle Triassic age for organic matter and for the development of a Triassic meteoric karst system immediately after Anisian carbonate sedimentation.

Retardation of uranium and thorium by a cementitious backfill developed for radioactive waste disposal

The solubility of uranium and thorium has been measured under the conditions anticipated in a cementitious, geological disposal facility for low and intermediate level radioactive waste. Similar solubilities were obtained for thorium in all media, comprising NaOH, Ca(OH)2 and water equilibrated with a cement designed as repository backfill (NRVB, Nirex Reference Vault Backfill). In contrast, the solubility of U(VI) was one order of magnitude higher in NaOH than in the remaining solutions. The presence of cellulose degradation products (CDP) results in a comparable solubility increase for both elements. Extended X-ray Absorption Fine Structure (EXAFS) data suggest that the solubility-limiting phase for uranium corresponds to a becquerelite-type solid whereas thermodynamic modelling predicts a poorly crystalline, hydrated calcium uranate phase. The solubility-limiting phase for thorium was ThO2 of intermediate crystallinity. No breakthrough of either uranium or thorium was observed in diffusion experiments involving NRVB after three years. Nevertheless, backscattering electron microscopy and microfocus X-ray fluorescence confirmed that uranium had penetrated about 40 μm into the cement, implying active diffusion governed by slow dissolution-precipitation kinetics. Precise identification of the uranium solid proved difficult, displaying characteristics of both calcium uranate and becquerelite.

Thermodynamic equilibrium constants for important isosaccharinate reactions: A review

Isosaccharinic acid is a cellulose degradation product that can form in low-level nuclear waste repositories and is known to form strong complexes with many elements, including actinides, disposed of in these repositories. We 1) reviewed the available data for deprotonation and lactonisation constants of isosaccharinic acid, and the isosaccharinate binding constants for Ca, Fe(III), Th, U(IV), U(VI), Np(IV), Pu(IV), and Am(III), 2) summarized complexation constant values for predicting actinide behavior in geologic repositories in the presence of isosaccharinate, and 3) outlined additional studies to acquire reliable thermodynamic data where the available data are inadequate.

Study on process production of furfural and other chemicals from sugarcane bagasse in the phosphoric acid-tetrahydrofuran system

Cellulose degradation is inevitable during the production of furfural from biomass under the acidic systems; meanwhile, the simultaneous high yields of furfural and cellulose degradation product (5-HMF or levulinic acid) are hard to be achieved. To solve the problem and avoid the waste of cellulose, a method of producing furfural and preserving cellulosic residue was explored. Sugarcane bagasse was firstly pre-treated by phosphoric acid to obtain soluble xylo-oligosaccharides. And compared to the low furfural yields in phosphoric acid-water system based on response surface analysis, high furfural yields were obtained in the phosphoric acid-tetrahydrofuran (THF) system, meanwhile only trace cellulose was degraded. Furthermore, by a two-step rising temperature method, furfural yield reached to 66.59 mol%, and cellulose was depolymerised into glucooligosaccharides. After recovery of furfural, this research also investigated the conversion of glucooligosaccharides catalysed by the residual phosphoric acid, and it was found levulinic acid and extremely high yields of formic acid generated at 200°C. [Received: January 12, 2016; Accepted: July 27, 2016]

Study on process production of furfural and other chemicals from sugarcane bagasse in the phosphoric acid-tetrahydrofuran system

Cellulose degradation is inevitable during the production of furfural from biomass under the acidic systems; meanwhile, the simultaneous high yields of furfural and cellulose degradation product (5-HMF or levulinic acid) are hard to be achieved. To solve the problem and avoid the waste of cellulose, a method of producing furfural and preserving cellulosic residue was explored. Sugarcane bagasse was firstly pre-treated by phosphoric acid to obtain soluble xylo-oligosaccharides. And compared to the low furfural yields in phosphoric acid-water system based on response surface analysis, high furfural yields were obtained in the phosphoric acid-tetrahydrofuran (THF) system, meanwhile only trace cellulose was degraded. Furthermore, by a two-step rising temperature method, furfural yield reached to 66.59 mol%, and cellulose was depolymerised into glucooligosaccharides. After recovery of furfural, this research also investigated the conversion of glucooligosaccharides catalysed by the residual phosphoric acid, and it was found levulinic acid and extremely high yields of formic acid generated at 200°C. [Received: January 12, 2016; Accepted: July 27, 2016]

Profiles of Volatile Organic Compounds in Biochar: Insights into Process Conditions and Quality Assessment

Sustainable application of biochar to soil requires careful consideration of sorbed mobile compounds that can be released into the environment and their relationship with bulk chemical properties. Seven biochars were produced by pyrolysis of corn stalk from 350 to 650 °C, and residual volatile organic compounds (VOCs) were investigated by head space solid-phase microextraction and gas chromatography–mass spectrometry. Over 80 compounds were detected in poorly carbonized biochars, including thermal degradation products of lignin (2-methoxyphenols), cellulose and hemicellulose (1,4:3,6-dianhydro-β-d-glucopyranose, C1–C3 furans and furanones, C1–C2 cyclopentenones), lipids (aromatic and C2–C8 aliphatic acids), and proteins (aromatic nitriles, amides). The presence of potentially harmful compounds, such as benzene, toluene, ethylbenzene, xylenes, phenols, volatile fatty acids, and polycyclic aromatic hydrocarbons, highlights the importance of controlling the biochar production process. Statistically significa...

Microbial Community Evolution Is Significantly Impacted by the Use of Calcium Isosaccharinic Acid as an Analogue for the Products of Alkaline Cellulose Degradation.

Diasteriomeric isosaccharinic acid (ISA) is an important consideration within safety assessments for the disposal of the United Kingdoms’ nuclear waste legacy, where it may potentially influence radionuclide migration. Since the intrusion of micro-organisms may occur within a disposal concept, the impact of ISA may be impacted by microbial metabolism. Within the present study we have established two polymicrobial consortia derived from a hyperalkaline soil. Here, α-ISA and a diatereomeric mix of ISAs’ were used as a sole carbon source, reflecting two common substrates appearing within the literature. The metabolism of ISA within these two consortia was similar, where ISA degradation resulted in the acetogenesis and hydrogenotrophic methanogenesis. The chemical data obtained confirm that the diastereomeric nature of ISA is likely to have no impact on its metabolism within alkaline environments. High throughput sequencing of the original soil showed a diverse community which, in the presence of ISA allowed for the dominance the Clostridiales associated taxa with Clostridium clariflavum prevalent. Further taxonomic investigation at the genus level showed that there was in fact a significant difference (p = 0.004) between the two community profiles. Our study demonstrates that the selection of carbon substrate is likely to have a significant impact on microbial community composition estimations, which may have implications with respect to a safety assessment of an ILW-GDF.

Hydrothermal treatment of biomass for energy and chemicals

Pyrolysis oils are a product of fast pyrolysis or liquefaction of biomass. Those dark brown organic liquids are chemically a complex mixture and/or emulsion of water and degradation products of lignin (e.g. guaiacols, catechols, syringols, vanillins), cellulose (such as levoglucosan, dehydrated sugars, di-sugars, furancarboxaldehydes), and hemicellulose (such as acetic acid, formic acid). Composition strongly depends on conditions of pyrolysis process and great variety of biomass feedstock such as grasses and trees, and other sources of ligno-cellulosic material, derived from municipal waste, food processing wastes, forestry wastes and pulp and paper by-products. The present contribution will present an overview of current high pressure processes for treatment of biomass for production of energy and chemicals as well as the fundamental studies of phase equilibria of the systems pyrolysis oil/gas, which are crucial in biorefinery process design. In particular, phase equilibria of binary and ternary systems consisting of pyrolysis oil/supercritical fluid (pyrolysis oil/CO2) and (pyrolysis oil/H2) was studied in addition to the phase behavior of ternary systems of (pyrolysis oil/diesel/CO2) and (pyrolysis oil/tail water/CO2). These data are important for design of separation processes as well as for the application of these substances for commercial fuels.

The solubility of nickel and its migration through the cementitious backfill of a geological disposal facility for nuclear waste

This work describes the solubility of nickel under the alkaline conditions anticipated in the near field of a cementitious repository for intermediate level nuclear waste. The measured solubility of Ni in 95%-saturated Ca(OH)2 solution is similar to values obtained in water equilibrated with a bespoke cementitious backfill material, on the order of 5×10−7M. Solubility in 0.02M NaOH is one order of magnitude lower. For all solutions, the solubility limiting phase is Ni(OH)2; powder X-ray diffraction and scanning transmission electron microscopy indicate that differences in crystallinity are the likely cause of the lower solubility observed in NaOH. The presence of cellulose degradation products causes an increase in the solubility of Ni by approximately one order of magnitude. The organic compounds significantly increase the rate of Ni transport under advective conditions and show measurable diffusive transport through intact monoliths of the cementitious backfill material.