The understanding of lignin softening and pyrolysis is important for developing lignocellulosic biorefinery in order to produce carbon fibers, polymers additives, green aromatics, or biofuels. Protobind lignin (produced by soda pulping of a wheat straw) was characterized by thermogravimetry, calorimetry (for glass transition temperature and heat of pyrolysis reactions), in situ 1H NMR (for the analysis of the mobility of protons upon lignin thermal conversion), and solution-state 13C and 31P NMR (determination of functional groups in lignin). In situ rheology reveals the real-time viscoelastic behavior of lignin as a function of temperature. Upon heating, lignin undergoes softening, through glass transition overlapped with depolymerization, and is followed by the solidification of the softened material by cross-linking reactions. The lignin residues were quenched within the rheometer at the midpoint temperatures of softening and solidification regions and were further analyzed by elemental analysis, GPC-UV of acetylated THF soluble fractions, FTIR, solid 13C NMR, and laser desorption ionization (LDI) combined with very high-resolution mass spectrometry (HRMS). We present the first report on lignin biochars analysis by LDI-HRMS. NMR and FTIR analyses provide the evolution of functional moieties in lignin residues. 13C NMR, GPC-UV, and LDI FTICRMS analyses depict the depolymerization mechanism combined with cross-linking and demethoxylation reactions. An overall physical and chemical mechanism for the thermal conversion of alkali lignin is proposed based on these complementary analyses.

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Biomass, the fibrous material derived from plant cell walls, is a potentially clean and renewable nonfood feedstock for liquid fuel and chemical production in future biorefineries. The capability of ionic liquids to act as selective solvents and catalysts for biomass processing has already been proven. Thus, they are considered as an alternative to conventional solvents. Nevertheless, phase equilibria with biomass derived compounds is still lacking in the literature. To overcome the lack of experimental data on phase equilibria of biomass carbohydrates in ionic liquids, the solubility of d-glucose in four ionic liquids was measured within a temperature range from 283 to 373 K. Solubility data were successfully correlated with local composition thermodynamic models such as NRTL and UNIQUAC. In this work, the possibility of extracting glucose from these ionic liquids using the antisolvent method has been also evaluated. The parameters affecting the extraction process are the ionic liquid type, ethanol/ionic liquid ratio, temperature, water content, and time. Results indicate that ethanol can be successfully used as an antisolvent to separate glucose from ionic liquids.

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In this paper, for the first time, faujasite Y zeolite impregnated with iron (III) was employed as a catalyst to remove a real cocktail of micropollutants inside real water samples from the Meurthe river by the means of the heterogeneous photo-Fenton process. The catalyst was prepared by the wet impregnation method using iron (III) nitrate nonahydrate as iron precursor. First, an optimization of the process parameters was conducted using phenol as model macro-pollutant. The hydrogen peroxide concentration, the light wavelength (UV and visible) and intensity, the iron loading immobilized, as well as the pH of the solution were investigated. Complete photo-Fenton degradation of the contaminant was achieved using faujasite containing 20 wt.% of iron, under UV light, and in the presence of 0.007 mol/L of HO at pH 5.5. In a second step, the optimized process was used with real water samples from the Meurthe river. Twenty-one micropollutants (endocrine disruptors, pharmaceuticals, personal care products, and perfluorinated compounds) including 17 pharmaceutical compounds were specifically targeted, detected, and quantified. All the initial concentrations remained in the range of nanogram per liter (0.8-88 ng/L). The majority of the micropollutants had a large affinity for the surface of the iron-impregnated faujasite. Our results emphasized the very good efficiency of the photo-Fenton process with a cocktail of a minimum of 21 micropollutants. Except for sulfamethoxazole and PFOA, the concentrations of all the other microcontaminants (bisphenol A, carbamazepine, carbamazepine-10,11-epoxide, clarithromycin, diclofenac, estrone, ibuprofen, ketoprofen, lidocaine, naproxen, PFOS, triclosan, etc.) became lower than the limit of quantification of the LC-MS/MS after 30 min or 6 h of photo-Fenton treatment depending on their initial concentrations. The photo-Fenton degradation of PFOA can be neglected. The photo-Fenton degradation of sulfamethoxazole obeys first-order kinetics in the presence of the cocktail of the other micropollutants.

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