A Strategy to Valorize a By-Product of Pine Wood (Pinus pinaster) for Copper Removal from Aqueous Solutions

This study describes the valorization of a pine wood by-product (Pinus pinaster) in the form of individualized fibers to a complex copper or more broadly metals present in an aqueous solution using a batch process. The adsorption results show that pine fibres activated by sodium carbonate are effective in recovering copper ions from monocontaminated or polycontaminated solutions of varying concentrations in a few minutes. One gram of material captures 2.5 mg of copper present in 100 mL of solution at pH 5 in less than 10 min. The results are perfectly reproducible and independent of pH between 3 and 5. The presence of the Na+ cation at concentrations of 0.1 M has no impact on material performance, unlike that of Ca2+ ions, which competes with Cu2+ ions for active sites. The adsorption process can be considered as rapid, as most of the copper is adsorbed within the first 10 min of exposure. Investigation of modeling possibilities shows some limitations. Indeed, the Weber and Morris and Elovich models show poor possibilities to describe all the kinetic data for copper adsorption on fibres. This may prove that the mechanism is far more complex than simple physisorption, chemisorption and/or diffusion. Complexation by wood fibers can be extended to solutions containing several types of metals. The results of this study show that the field of selective metal recovery could be a new way of valorizing by-products from the wood industry

LIGNIN UPGRADING TO AROMATICS BY A HETEROGENEOUS GOLD CATALYST IN AQUEOUS MEDIA

International @ CDFA+CCB:PFO:LDJInternational audienceWith the depletion of fossil fuels, the need to develop green technologies to produce energy or chemicals increased. Lignocellulosic biomass is a promising candidate regarding its renewability and availability at a low price. Lignin, which represents ca. 30%, is a macromolecule formed by the random polymerization of three monomers: p-coumaryl, coniferyl and sinapyl alcohol[1]. This results in a three-dimensional phenolic bio-polymer. Those structures depend on the source and extraction process. Nowadays it is essentially produced by the Kraft process (paper pulp production) and used as energy source for it[2]. Nevertheless, a part of that lignin can be redirected for other applications without endangering this industry.In order to valorize lignin, we studied its transformation to produce aromatic building blocks for polymers or fine chemicals by catalytic oxidation using heterogeneous catalysts in aqueous media under mild conditions. In this work, a softwood lignin, provided by FCBA after extraction and purification from a Kraft black liquor by precipitation with H2SO4, was engaged.Alkaline solutions of lignin (0.5%wt) were treated in the presence of Au/TiO2 catalyst in a 300mL batch reactor under 40bar air at temperature varying from 50°C to 150°C. At completion, the catalyst was separated by filtration. The complexity of the reaction mixture encouraged us to design a protocol allowing evaluation of the transformation that occurred during the reaction. High molecular weight molecules were precipitated by HCl addition and separated by centrifugation giving so-called "precipitate". Then, the remaining aqueous phase was washed with dichloromethane to recover monomeric fraction while oligomeric fraction remained in water. This fractionation allowed careful analyses of the different fractions by complementary techniques (IR, NMR, GC...). The influence of different parameters was evaluated throughout our study. It was shown that base loading has a great impact on the rate of lignin depolymerization. Indeed, increasing NaOH concentration resulting in a decreased "precipitate" amount. However, it seems that addition of catalyst had no notable effect on this aspect(fig. 1). In both cases, the recovered precipitate looks alike but completely different from the starting lignin. As a matter of fact, IR analysis showed disappearance of a characteristic band of lignin corresponding to aromatic vibrations together with apparition of bands corresponding to carbonyls. Concerning the monomeric fraction, rising the amount of base improved the yields toward the target molecules; however, adding the catalyst lowered the yields in monomers by favoring over-oxidation(fig. 2).In conclusion, the catalytic oxidation of lignin has been realized in an alkaline media under mild conditions. While the base seems to favor the formation of monomeric compounds, the use of gold catalyst lowered them due to over-oxidation

LIGNIN UPGRADING TO AROMATICS BY A HETEROGENEOUS GOLD CATALYST IN AQUEOUS MEDIA

International @ CDFA+CCB:PFO:LDJInternational audienceWith the depletion of fossil fuels, the need to develop green technologies to produce energy or chemicals increased. Lignocellulosic biomass is a promising candidate regarding its renewability and availability at a low price. Lignin, which represents ca. 30%, is a macromolecule formed by the random polymerization of three monomers: p-coumaryl, coniferyl and sinapyl alcohol[1]. This results in a three-dimensional phenolic bio-polymer. Those structures depend on the source and extraction process. Nowadays it is essentially produced by the Kraft process (paper pulp production) and used as energy source for it[2]. Nevertheless, a part of that lignin can be redirected for other applications without endangering this industry.In order to valorize lignin, we studied its transformation to produce aromatic building blocks for polymers or fine chemicals by catalytic oxidation using heterogeneous catalysts in aqueous media under mild conditions. In this work, a softwood lignin, provided by FCBA after extraction and purification from a Kraft black liquor by precipitation with H2SO4, was engaged.Alkaline solutions of lignin (0.5%wt) were treated in the presence of Au/TiO2 catalyst in a 300mL batch reactor under 40bar air at temperature varying from 50°C to 150°C. At completion, the catalyst was separated by filtration. The complexity of the reaction mixture encouraged us to design a protocol allowing evaluation of the transformation that occurred during the reaction. High molecular weight molecules were precipitated by HCl addition and separated by centrifugation giving so-called "precipitate". Then, the remaining aqueous phase was washed with dichloromethane to recover monomeric fraction while oligomeric fraction remained in water. This fractionation allowed careful analyses of the different fractions by complementary techniques (IR, NMR, GC...). The influence of different parameters was evaluated throughout our study. It was shown that base loading has a great impact on the rate of lignin depolymerization. Indeed, increasing NaOH concentration resulting in a decreased "precipitate" amount. However, it seems that addition of catalyst had no notable effect on this aspect(fig. 1). In both cases, the recovered precipitate looks alike but completely different from the starting lignin. As a matter of fact, IR analysis showed disappearance of a characteristic band of lignin corresponding to aromatic vibrations together with apparition of bands corresponding to carbonyls. Concerning the monomeric fraction, rising the amount of base improved the yields toward the target molecules; however, adding the catalyst lowered the yields in monomers by favoring over-oxidation(fig. 2).In conclusion, the catalytic oxidation of lignin has been realized in an alkaline media under mild conditions. While the base seems to favor the formation of monomeric compounds, the use of gold catalyst lowered them due to over-oxidation

Low formaldehyde emitting biobased wood adhesives manufactured from mixtures of tannin and glyoxylated lignin

NatuurwetenskappeChemie & PolimeerwetenskapPlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Evolution and impact of cellulose architecture during enzymatic hydrolysis by fungal cellulases

International audienc

Kinetic modeling of β-glucosidases and cellobiohydrolases involved in enzymatic hydrolysis of cellulose

International audienc

Pilot-scale elaboration of graphite/microfibrillated cellulose anodes for Li-ion batteries by spray deposition on a forming paper sheet

A new spray coating water-based process is here proposed for the rapid and reliable large-scale production of self-standing Li-ion battery electrodes using truly natural microfibrillated cellulose as binder. The graphite/carbon black microfibrillated cellulose slurry was spray coated on a wet paper substrate which, subsequently pressed and dried on a conventional pilot paper machine, led to the formation of a bilayered electrode with excellent mechanical properties, cycling performances vs Li metal comparable to those of anodes with standard composition, (i.e. Young Modulus of 2.5 GPa and specific capacity of 350 mAh g-1 at 0.1 C) but a Coulombic efficiency (ca. 98% in the first 50 cycles) which needs to be improved to maintain good cycling performances in Li-ion systems. This work demonstrated that well-established industrial papermaking techniques and materials can be adapted to the elaboration of well-functioning electrodes thus paving the way for the transfer the Li-ion battery industrial area of high- throughput paper production technologie