The Use of CO2 in the Production of Bioplastics for an Even Greener Chemistry

International audienceThe high life expectancy of the world population provokes increase in demand for food and energy. As a result, the intense industrialization and the application of fossil sources is responsible for high levels of CO2 emission and waste generation. To mitigate the CO2 emission a practical solution at the very short term is urgently needed. The capture of CO2 and its application in chemical processes for the valorization of residual biomass are of great importance nowadays. The application of CO2 in the selective carboxylation of furoic acid for the production of 2,5-furandicarboxylic acid (FDCA), a bio-based monomer, has been an important step towards obtaining biopolymers to replace petroleum-based plastics such as polyethylene terephthalate (PET). In this project report, we discuss on the current challenges for obtaining the 2,5-FDCA precursor from the furfural in two main routes involving oxidation and carboxylation via heterogeneous catalysis. We present the main objectives and discuss the importance of this research for the development of more sustainable processes

Sonochemical synthesis of FeO@NH-mesoporous silica@Polypyrrole/Pd: A core/double shell nanocomposite for catalytic applications

International audienc

Mesoporous silica nanoparticles for the encapsulation of essential oils and the improvement of their activity against Fusasrium avenaceum and its production of enniatins

International audienceDespite the in vitro efficacy of various essential oils (EOs), their practical use to control toxigenic Fusarium spp is limited by their high volatility and sensitivity to UV and oxidation. Their nano-encapsulation can provide protection for the active volatile molecules and allow for a gradual release into the environment. Mesoporous silica nanoparticles (MSNPs) are inert, mechanically stable, stable in suspension in an aqueous medium and their specific surface area is very suitable for functionalization. We have used them for the encapsulation of EOs with antifungal and antimycotoxin activity Mesoporous silica nanoparticles synthesis tetraethyl orthosilicate (TEOS

Study of the Direct CO2 Carboxylation Reaction on Supported Metal Nanoparticles

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Brewer’s Spent Grain Biochar: Grinding Method Matters

The present work is based on the principle of biomass waste valorization. Brewer’s spent grains (BSG) come from breweries as by-products. Their huge amount of production on an industrial scale should focus our attention on their valorization, which creates challenges as well as opportunities. One way to valorize BSG by-products is to convert them into biochar, a functional material with multiple potential applications. With an emphasis on sustainable development and the circular economy, in this work, we focused on a comparative study of the different mechanical processes of BSG grinding and their effect on the resulting biochar formed after pyrolysis. Home appliances such as blenders, coffee mills, and mortar and pestles were used for this purpose. FESEM images confirmed the successful creation of five different morphologies from the same BSG under the same pyrolysis conditions. Interestingly, a novel Chinese tea leaf egg-like biochar was also formed. It was found that a series of physical pretreatments of the biomass resulted in the reduced roughness of the biochar surface, i.e., they became smoother, thus negatively affecting the quality of the biochar. XRD revealed that the biomass physical treatments were also reflected in the crystallinity of some biochar. Via a Raman study, we witnessed the effect of mechanical pressure on the biomass for affecting the biochar features through pressure-induced modifications of the biomass’s internal structure. This induced enhanced biochar graphitization. This is a good example of the role of mechanochemistry. DSC revealed the thermochemical transformation of the five samples to be exothermic reactions. This study opens up an interesting possibility for the synthesis of biochar with controlled morphology, crystallinity, degree of graphitization, and heat capacity

Versatile biogenesis of Silver-Copper nanoparticles over arylated pulp sugarcane bagasse- derived biochar: high catalytic performance

Agrowaste-derived materials for the supporting of nanocatalysts is attracting a great attention due to the abundance and the physicochemical features they provide as bio-sourced underlying materials. The main idea is built around the conversion of junk material into functional material, a journey of waste from "trash to treasure". Herein, we suggest a versatile method to elaborate phytochemically reduced Ag/Cu nanoparticles supported on aryl-sulfonated sugarcane bagasse pulp-derived biochar. Biochar was first prepared by a slow pyrolysis of the biomass at 500°C under N2:H2 95%:5% inert atmosphere. Thereafter, in-situ arylation of the biochar surface has been performed to obtain SO3H-biochar. Silver and copper ions loading in SO3H-biochar has been established via a wet impregnation in a hydroalcoholic medium. Finally, the natural liquid extract of sugarcane bagasse has been employed to reduce the metallic ions instead of the toxic NaBH4 very commonly used, the obtained SO3H-biochar@Ag/Cu has been characterized by XRD, XPS, SEM and RAMAN spectroscopy. The catalytic activity of the nanocomposite has been investigated in the oxidative degradation of malachite green oxalate. A total mineralization of the dye has been registered and the experimental data was found to give a relatively good fitting to the pseudo-first-order model with a mineralization apparent constant rate equals to 65 10-3 min-1

Brewer’s Spent Grain Biochar: Grinding Method Matters

The present work is based on the principle of biomass waste valorization. Brewer’s spent grains (BSG) come from breweries as by-products. Their huge amount of production on an industrial scale should focus our attention on their valorization, which creates challenges as well as opportunities. One way to valorize BSG by-products is to convert them into biochar, a functional material with multiple potential applications. With an emphasis on sustainable development and the circular economy, in this work, we focused on a comparative study of the different mechanical processes of BSG grinding and their effect on the resulting biochar formed after pyrolysis. Home appliances such as blenders, coffee mills, and mortar and pestles were used for this purpose. FESEM images confirmed the successful creation of five different morphologies from the same BSG under the same pyrolysis conditions. Interestingly, a novel Chinese tea leaf egg-like biochar was also formed. It was found that a series of physical pretreatments of the biomass resulted in the reduced roughness of the biochar surface, i.e., they became smoother, thus negatively affecting the quality of the biochar. XRD revealed that the biomass physical treatments were also reflected in the crystallinity of some biochar. Via a Raman study, we witnessed the effect of mechanical pressure on the biomass for affecting the biochar features through pressure-induced modifications of the biomass’s internal structure. This induced enhanced biochar graphitization. This is a good example of the role of mechanochemistry. DSC revealed the thermochemical transformation of the five samples to be exothermic reactions. This study opens up an interesting possibility for the synthesis of biochar with controlled morphology, crystallinity, degree of graphitization, and heat capacity

Encapsulation of <i>Ammoides pusila</i> Essential Oil into Mesoporous Silica Particles for the Enhancement of Their Activity against <i>Fusarium avenaceum</i> and Its Enniatins Production

Essential oils (EOs) that have antifungal activity and mycotoxin reduction ability are candidates to develop bioactive alternatives and environmentally friendly treatment against Fusarium species in cereals. However, their practical use is facing limitations such as high volatility, UV sensitivity, and fast oxidation. Encapsulation techniques are supposed to provide protection to the EOs and control their release into the environment. Ammoides pusilla essential oil (AP-EO) proved to be an efficient inhibitor of Fusarium avenaceum growth and its enniatins (ENNs) production. In the present work, AP-EO was encapsulated, using the impregnation method, into mesoporous silica particles (MSPs) with narrow slit pores (average diameter = 3.1 nm) and coated with chitosan. In contact assays using an agar medium, the antifungal activity of AP-EO at 0.1 µL mL−1 improved by three times when encapsulated into MSPs without chitosan and the ENNs production was significantly inhibited both in coated and non-coated MSPs. Controls of MSPs also inhibited the ENNs production without affecting the mycelial growth. In fumigation experiments assessing the activity of the EO volatile compounds, encapsulation into MSPs improved significantly both the antifungal activity and ENNs inhibition. Moreover, coating with chitosan stopped the release of EO. Thus, encapsulation of an EO into MSPs improving its antifungal and antimycotoxin properties is a promising tool for the formulation of a natural fungicide that could be used in the agriculture or food industry to protect plant or food products from the contamination by toxigenic fungi such as Fusarium sp. and their potential mycotoxins

Unusual, hierarchically structured composite of sugarcane pulp bagasse biochar loaded with Cu/Ni bimetallic nanoparticles

Valorization of agro-wastes into high performance functional materials is a topic that is receiving growing interest. Agro-wastes could be converted into biochar by slow pyrolysis and could be even given high added value by in situ deposition of nanoparticles. Herein, we investigate for the first time the impregnation of copper and nickel nitrates on sugarcane pulp bagasse powder and its slow pyrolysis at 500 °C. The process permitted to obtain unusual hierarchically structured porous biochar material with 40 nm-sized immobilized bimetallic copper-nickel alloy nanoparticles. The materials were characterized by XRD, XPS, Raman spectroscopy, TGA and SEM. As the pure biochar does not exhibits any highly porous structure, it is suggested that copper and nickel salts, or the metallic nanoparticles, are responsible for the fishing net-like structure obtained for the underlying biochar. The alloyed metal nanoparticles are extremely well dispersed over the biochar, with narrow size distribution (403 nm). This work clearly demonstrates that sugarcane pulp bagasse has a particular behavior and could provide highly porous biochar, in one step, for catalytic and other applications where high porosity and surface area are required. More importantly, such a porosity does not require any harsh acidic or basic treatment, and only the catalyst precursors are required