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International audience; Waterworks sludge refers to the inevitable suspended and dissolved solids produced during the water purification process when producing tap water where Al-salt and/or Fe-salt are used as coagulant worldwide. Waterworks sludge is dewatered and the resultant cakes have been treated as “waste” for landfill as their major final disposal solution for a long time in practice. As waterworks sludge is the residual of potable water treatment process, it is not harmful and without toxic elements such as heavy metals in most cases in comparison to sewage sludges for instance. Actually, waterworks sludge is an underrated material with huge potential for beneficial reuse as raw material in water and environmental engineering. However, little was significantly progressed on this topic until the last two decades. Research and development (R&D) with special interest and focus on waterworks sludge reuse was conducted in our group in the last 15 years and this paper reports and discusses the main work and its novel application profile. Overall, it is believed that the R&D of waterworks sludge is useful and will help to develop national strategy of the entire waterworks sludge management, allowing its transformation from a “waste” into value-added products, and thus contribute to sustainable development.

International audience; Modeling approaches are generally used to describe mercury transformations in a single step of flue gas treatment processes. However, less attention has been given to the interactions between the different process stages. Accordingly, the mercury removal performance of a full-scale solid waste incineration plant, equipped with a dry flue gas treatment line was investigated using two complementary modeling strategies: a thermochemical equilibrium approach to study the mercury transformation mechanisms and speciation in the flue gas, and a kinetic approach to describe the mercury adsorption process. The modeling observations were then compared to real-operation full-scale data. Considering the typical flue gas composition of waste incineration facilities (high concentrations of HCl compared to Hg), it was found that a process temperature decrease results in better mercury removal efficiencies, associated with a higher oxidation extent of Hg in HgCl2, and the enhancement of the sorbent capacity. Improvements can also be attained by increasing the sorbent injection rate to the process, or the solid/gas separation cycles. An empirical correlation to predict the mercury removal efficiency from the main operating parameters of dry flue gas treatment units was proposed, representing a useful tool for waste incineration facilities. The presented modeling approach proved to be suitable to evaluate the behavior of full-scale gas treatment units, and properly select the most adequate adjustments in operating parameters, in order to respect the increasingly constraining mercury emissions regulations.

International audience; Plastics generally play a very important role in a plethora of industries, fields and our everyday lives. In spite of their cheapness, availability and important contributions to lives, they however, pose a serious threat to the environment due to their mostly non-biodegradable nature. Recycling into useful products can reduce the amount of plastic waste. Thermal degradation (Pyrolysis) of plastics is becoming an increasingly important recycling method for the conversion of plastic materials into valuable chemicals and oil products. In this work, waste Polyethylene terephthalate (PET) water bottles were thermally converted into useful gaseous and liquid products. A simple pyrolysis reactor system has been used for the conversions with the liquid product yield of 65 % at a temperature range of 400°C to 550°C. The chemical analysis of the pyrolytic oil showed the presence of functional groups such as alkanes, alkenes, alcohols, ethers, carboxylic acids, esters, and phenyl ring substitution bands. The main constituents were 1-Tetradecene, 1-Pentadecene, Cetene, Hexadecane, 1-Heptadecene, Heptadecane, Octadecane, Nonadecane, Eicosane, Tetratetracontane, 1-Undecene, 1-Decene). The results are promising and can be maximized by additional techniques such as hydrogenation and hydrodeoxygenation to obtain value-added products.

International audience; The dry reforming of methane over hydroxyapatite‐ and alumina/magnesia (commercial Pural MG 30)‐supported nickel catalysts was investigated. The catalytic performance of the catalysts prepared with fresh supports highly depended on the basicity, the metal‐support interaction, and the metal particle size. Calcination of the supports at 1200 °C for 5 h made the catalysts less active because of specific surface area reduction and basicity destruction. However, this treatment allowed avoiding any further catalyst deactivation by thermal sintering and maintained excellent catalytic stability over 300 h of time‐on‐stream. These tests under simulated industrial conditions (high contact time and long time‐on‐stream) showed the competitiveness of the prepared catalysts in this important catalytic process.

International audience; This paper presents the results of the experimental and analytical studies of the mechanical and thermal properties of laterite composites mixed with reprocessed low-density polyethylene waste (LDPE), calcium phosphate (CaP) and phosphogypsum wastes, and biochar to form brick composites. Bricks with mixtures of 20% by volume LDPE, 15% by volume CaP, and 15% by volume gypsum were shown to have excellent compressive strength, flexural strength, and fracture toughness. The composites with 1% by volume LDPE and 15% by volume biochar had the best blend of mechanical properties, such as flexural strength and fracture toughness, after sintering for ∼24h. There was a linear association between the strength and the weight loss of the bricks. Scanning electron microscopy and optical microscopy images revealed evidence of crack bridging by LDPE particles. The laterite–LDPE composite mixed with 5%, 10%, and 15% by volume biochar had sintering temperatures of ∼850°C, ∼720°C, and ∼710°C, respectively, after undergoing softening, cold crystallization, and cooling.

International audience; Three main components of biomass were pyrolyzed individually in a closed reaction system at 500–700 °C for 60s and 90s. Then bio-oil heavy compounds were further analyzed with Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) and Kendrick mass defect (KMD) analysis. The evolution paths of heavy compounds for the different pyrolysis stages were proposed. It was found that the sugars and phenolic-like species in heavy compounds were the most active substances during secondary reactions. Moreover, the rising temperature promoted this secondary reaction of phenolic-like species as the decrease in their abundances growing from 13% to 54%, while contrarily inhibited it for hemicellulose as the decrease in their abundances changing from 44% to −2%. The lignin-derived lipids and unsaturated hydrocarbons that generated in the secondary reactions increased with rising temperature. KMD analysis showed that the heavy compounds of cellulose and hemicellulose prefer homologous evolution during pyrolysis, while those of lignin had more complex evolution paths like cracking and recombination.

International audience; Water treatment residuals, sewage sludge and dredged sediments, hereinafter referred to as sludge, share common features, like inherent high moisture content, high organic and mineral pollutant load and above all a pasty consistency. Several recovery opportunities exist. However, sludge composition is closely correlated with human activity and the design of the recovery processes requires knowledge of physical, thermal or biological characteristics of the sludge that will be processed, often even before the specific sludge exists. Therefore, sludge characterization is a key challenge for the process design, control and optimization and further valorization. The present chapter is divided into four parts dedicated to the composition, the material properties, the dynamic processing properties and the environmental assessments, respectively. Standard tests methods for the characterization of solids and water distribution in sludge are introduced first. Then, the fate of organic constituents, inorganic nonmetallic and metallic constituents as well as pathogenic organism. In the second part, standard and state-of-the-art methods for the characterization of chemical, physical and thermal properties of sludge are described. Dynamic tests, required for the selection and design of conventional processes for sludge concentration and conveying, are detailed in the third part. Finally, methods for assessing the environment impacts of sludge and secondary raw materials derived from sludge are addressed.

International audience; Green chemistry started for the search of benign methods for the development of nanoparticles from nature and their use in the field of antibacterial, antioxidant, and antitumor applications. Biowastes are eco-friendly starting materials to produce typical nanoparticles with well-defined chemical composition, size, and morphology. Cellulose, starch, chitin and chitosan are the most abundant biopolymers around the world. All are under the polysaccharides family in which cellulose is one of the important structural components of the primary cell wall of green plants. Cellulose nanoparticles can be extracted from agrowaste resources such as jute, coir, bamboo, and pineapple leaves, coir etc. Chitin is the second most abundant biopolymer after cellulose, it is a characteristic component of the cell walls of fungi, the exoskeletons of arthropods and nanoparticles of chitin can be extracted from shrimp and crab shells. Chitosan is the derivative of chitin, prepared by the removal of acetyl group from chitin. Starch nanoparticles can be extracted from tapioca and potato wastes. The preparation of these nanoparticles includes both series of chemical as well as mechanical treatments; crushing, grinding, alkali, bleaching and acid treatments. Transmission electron microscopy, scanning electron microscopy and atomic force microscopy are used to investigate the morphology of nanoscale biopolymers. Fourier transform infrared spectroscopy and X-ray diffraction are being used to study the functional group changes, crystallographic texture of nanoscale biopolymers respectively. Since large quantities of bio wastes are produced annually, further utilization of cellulose, starch and chitins as functionalized materials is very much desired. These nanoparticles can be converted into smart and functional materials by functionalization through chemical modifications due to the presence of large amount of hydroxyl group on the surface. The cellulose, starch and chitin nanoparticles are currently obtained as aqueous suspensions which are used as reinforcing additives for high performance environment-friendly bio-degradable polymer materials. These nanocomposites are being used as biomedical composites for drug/gene delivery, nano-scaffolds in tissue engineering and cosmetic orthodontics. The reinforcing effect of these nanoparticles results from the formation of a percolating network based on hydrogen bonding forces.

International audience; Nowadays, the valorization of biomass, biowastes and by-products is among the key issue to be considered in the development of renewable energies from bioresources. Accurate analysis and characterization of these feedstocks is a crucial aspect in the understanding of their behaviour for further use. This chapter is focused on different characterization techniques which are commonly used up-to-date. They are classified in different categories: Sampling and storage; Proximate analysis; Ultimate analysis; Thermal analysis, Physical characterizations; Physico-chemical characterizations; Structural and textural characterizations; and Mechanical characterizations. For each of them, a general description of the technique is presented, followed by useful information on machines and experimental conditions such as sample preparation, sample pre-treatment, gas atmosphere, temperature program etc. Finally, examples, results treatment and exploitations will be provided to illustrate. This chapter provides an insight on generic and advanced characterization techniques for complex materials, such as biomass, biowastes and related bio-products, that will be again discussed along the handbook in the other chapters.

International audience; Particulate matter (PM), defined as the sum of solid and liquid particles suspended in the air, is often divided into two main groups: the coarse fraction with a size ranging from 2.5 to 10 µm (PM10–PM2.5), and the fine fraction with a size smaller than 2.5 µm (PM2.5). PM can be generated from various sources such as unpaved roads, vehicles, agricultural processes, uncovered soil, mining operations, as well as burning of fuels. Statistical data show that in Europe, 1378 thousand tonnes of PM2.5 are generated in year 2016, accounting for 5% of the total main air pollutants including sulphur oxides (SOx), nitrogen oxides (NOx), ammonia (NH3), and non-methane volatile organic compounds (NMVOCs) [1]. This chapter will focus on the thermochemical process of solid fuels such as biomass and biowaste, because these types of fuels today are increasingly being used for energy purposes and have contributed to PM emission in many regions of the world. The presence of PM is significantly relevant to health problems, smog formations, acid rain issues, and climate changes. Characterization of PM is challenging, because PM is not only made up of a complex group of components (mainly black carbon, organics, sulfate, nitrate, alkalis, trace metals, crustal material and salt), but also comes in a wide range of sizes from nanoparticles (diameter less than 0.05 µm) up to millimeter-sized particles. In addition to this, PM characteristics are also proven to depend on various factors such as fuel type, thermal technology and temperature. Detailed knowledge of PM released during biomass and biowaste thermal conversion is essential for controlling air emissions. Over the last decades, attempts have been made to better understand the mechanisms and pathways of PM formation. Also, techniques are developed for PM sampling, collection and analysis, as well as the understanding of its physical and chemical characteristics. This chapter will thus be structured into four parts dedicated to PM fundamentals, collection techniques, physical and chemical characterizations. Available sampling devices, standards, analytical methods and techniques will be presented. Advantages, disadvantages, and major applications regarding biomass and waste thermal conversion will also be presented.

International audience; In this chapter, the sampling, preconditioning, as well as physico-chemical, biochemical and thermal characterization methods for municipal solid waste are introduced. The typical equipment used in the sample preparation and characterization are illustrated. Furthermore, an overview of the characteristics of municipal solid waste is presented which provides a useful starting database.

International audience; Biomass resources for the production of renewable energy, chemicals and polymeric materials are abundant. In this chapter, these resources will be categorized into woody biomass, agricultural residues and waste, municipal solid waste, sewage sludge and aquatic plants. The origins, use and typical composition (physical, chemical and biological) of the different biomass types will be presented.

International audience; Solid co-products from biochemical, chemical and thermochemical processes of biomass and biowaste have gained momentum in utilization as secondary raw materials. These solids are carbon-based or mineral-based materials, and for their suitable use in a number of fields, various properties should be determined. This chapter addresses advanced techniques used to determine physical and chemical properties of these solid residues. For each technique, the basics and protocols are described. Post-treatment procedures and interpretation of the results obtained are also provided for some residues.

International audience; Syngas produced from biomass and biowaste gasification is a versatile renewable fuel and feedstock for chemical synthesis or heat and power production. Bio-syngas can be produced from different biomass feedstock (e.g. lignocellulosic biomass, pyrolysis oil, bioethanol, biogas) through thermal and/or catalytic reforming and gasification processes. The typical components of raw syngas can be classified into three groups: non-condensable gases (e.g. H2, CO, CH4 and CO2), condensable gases (e.g. H2O and tars) and impurities (e.g. HCl, NH3, H2S and particulates). Depending on the application, raw syngas may need to be cleaned of impurities and conditioned to adjust the H2/CO ratio in order to meet the requirements of environmental regulations and downstream processes respectively. Hence, an accurate characterization of the syngas chemical composition, at the different processing stages, is important to control and optimize the process efficiency. In this chapter, various methods and equipment for sampling, preconditioning and analyzing the three groups of syngas components will be discussed. Analyses of the equipment detection limits, gas matrix sensitivity, and overall accuracy will also be made.

International audience; Thermal energy storage (TES) has been identified as a breakthrough concept in development of renewable technologies. However, the main challenges are related to the development of competitive heat storage materials. Despite the number of studies on heat storage materials, the determination of new alternatives for next generation technologies is still open. In this regard, this paper presents the results of an experimental study of the physical, thermal and mechanical properties of SiC-doped ceramics as potential materials for TES applications. Two kinds of SiC additives (high and low densities) were incorporated with different percentages into the clay matrix in order to produce ceramics via the extrusion process. The addition of low-density SiC (true density 3.16 g cm−3) led to the increasing of porosity with large pore sizes and the decreasing of bulk density. Therefore, the thermal and mechanical properties are decreased up to − 50% for flexural strength and − 15% for thermal conductivity when 20 mass% of low-density SiC was used. On the other hand, when high-density SiC (true density 3.42 g cm−3) was used, properties of the clay ceramic were strongly improved: i.e., increase in the bulk density, decrease in the porosity, increase in the thermal conductivity and increase in the flexural strength. The best material was found with the addition of 20 mass% of high-density SiC which had a thermal conductivity of 1 W m−1 K−1, a specific heat capacity of 0.62 kJ kg−1 K−1 and a mechanical strength of 19.6 MPa. It also showed a high thermal stability after 20 successive heating/cooling cycles. Hence, this study provided a useful insight into how the SiC modified the microstructure and properties of fired clay ceramics. Thus, the current results suggest that clay ceramics with high-density SiC addition are promising materials for thermal energy storage applications

International audience; Molten salt pyrolysis driven by concentrated solar radiation is well positioned to utilize solar energy and lignite effectively. This study focused on the effects of temperature (500, 600, 700 and 800 °C) and molten carbonate salt (Li2CO3-Na2CO3-K2CO3) on properties of char obtained from lignite pyrolysis, as well as gas and tar products for revealing their formation mechanism and transformation process. Molten salt pyrolysis of HulunBuir lignite produced more gas products and less char compared to conventional pyrolysis owing to the enhanced heat transfer and catalytic effect of molten salt. The char yield decreased from 58.4% to 43.4%, and the gas yield (especially CO2, H2 and CO) increased from 28.3% to 46.1% at 800 °C. CO2, CO and H2 production increased about 60.43%, 103.42% and 65.2% at 800 °C, respectively. Additionally, the presence of molten salt improved the tar quality with more hydrocarbon content (maximum increase of 5.8%) and less oxygenated compounds. The structure and reactivity relationship of char was characterized by XRD, BET, SEM, FTIR, Raman spectroscopy and TGA. Molten salt generated char had a higher reactivity due to the increase of disorder, surface area, microporosity (maximum of 71.74%) and active sites.

International audience; The carbonation of residual brines generates large volumes of carbonate-based solid wastes. Physicochemical properties of these solids are adequate for acid-gas removal. This work studies the valorization of calcium carbonated-based solid wastes for efficient H2S removal from air at low concentrations (≤200 ppmv) in a three-phase semi-continuous reactor. Synthetic air polluted with H2S was bubbled into the slurry of two different wastes in a stirred tank to evaluate their effect for H2S removal. The efficiency of H2S removal was kept constant and could reach up to 98% during 8 h of reaction. Adequate physico-chemical characterization of used sorbents allowed understanding the interaction of sulfide species with sorbent particles. Thus, the reaction pathway for H2S removal was determined. It has been demonstrated that the dissolution of H2S gas at the gas-liquid interface was then accelerated by high basicity of calcium carbonate-based wastes, followed by the oxidation of dissolved sulfide species. This last was catalyzed by metals and metals oxides which were initially present in the solid wastes. The results obtained demonstrate the possibility to valorize the carbonates which have been precipitated during the carbonation of industrial brines to develop a low cost H2S removal process.

International audience; Waste-to-Energy (WtE) has gradually constituted one of the most important options to achieve energy recovery from municipal solid waste (MSW). However, the environmental sustainability of a specific WtE system varies with used technologies and geographic differences. As a result, three representative WtE systems are compared using life cycle assessment (LCA): a gasification-based WtE plant in Finland, mechanical-grate incineration in France, and circulating fluidized bed incineration in China. Results show that the overall environmental performance of the gasification system is better than incineration. The use of gasification technology, attributed to an intermediate syngas purification step, can provide benefits of both reducing the stack emissions and increasing the energy efficiency. Regional waste management, especially related to MSW caloric value and emission regulation, are determining factors for a preferable performance of the incineration in France over that in China. Sensitivity and uncertainty analyses further address key variations such as choice of MSW composition, basis of displaced electricity, energy recovery mode, and application of “best-available technology” dedicated to incineration. It is found that the most sensitive parameters influencing the LCA results are: electricity recovery, CO2 emission, and NOx emission. In the future, use of the source-separated high caloric waste combined with a more stringent emission standard can efficiently improve MSW incineration in China. Bottom ash recycling for metals and materials is highly applicable regarding incineration in France. This presented study can overall contribute to the development of specific WtE technology and local waste management plan for decision-makers.

International audience; Additional options for the sustainable treatment of municipal sludge are required due to the significant amounts of sludge, high levels of nutrients (e.g., C, N, and P), and trace constituents it contains. Hydrothermal processing of municipal sludge has recently been recognized as a promising technology to efficiently reduce waste volume, recover bioenergy, destroy organic contaminants, and eliminate pathogens. However, a considerable amount of solid residue, called hydrochar, could remain after hydrothermal treatment. This hydrochar can contain abundant amounts of energy (with a higher heating value up to 24 MJ/kg, dry basis), nutrients, and trace elements, as well as surface functional groups. The valorization of sludge-derived hydrochar can facilitate the development and application of hydrothermal technologies. This review summarizes the formation pathways from municipal sludge to hydrochar, specifically, the impact of hydrothermal conditions on reaction mechanisms and product distribution. Moreover, this study comprehensively encapsulates the described characteristics of hydrochar produced under a wide range of conditions: Yield, energy density, physicochemical properties, elemental distribution, contaminants of concern, surface functionality, and morphology. More importantly, this review compares and evaluates the current state of applications of hydrochar: Energy production, agricultural application, adsorption, heterogeneous catalysis, and nutrient recovery. Ultimately, along with the identified challenges and prospects of valorization approaches for sludge-derived hydrochar, conceptual designs of sustainable municipal sludge management are proposed.

Kitchen waste (KW) has gradually become a prominent problem in municipal solid waste treatment. Hydrothermal liquefaction (HTL) is a promising method used to make fuel oil from food and KW. However, the upgrading of bio-oil is particularly important for the sake of industrial reuse. In this study, the KW from university restaurants was subjected to HTL experiments in order to study theoretical feasibility. With the change of conversion temperature and residence time, the optimal conversion working conditions in this study were determined according to the quality and yield of the bio-oil. Moreover, the bio-oil upgrading effects of different additives (hydrogen chloride, sodium hydroxide, and iron(III) chloride) on the HTL of KW were studied. Alkaline additives have an inhibitory effect on the bio-oil yield and positive effect on coke yield. Acidic additives and iron (Fe)-containing additives can promote bio-oil yield. As an important aspect of upgrading, the effect on the nitrogen content of bio-oil with additives was revealed. The alkaline and Fe-containing additives have little effect on reducing the viscosity of the bio-oil while with the appropriate ratio (2.5 mol•kg−1) of acidic additives to the raw material, the static and dynamic fluidity of the oil phase products are reduced to about 0.1 Pa•s.

International audience; A novel alum sludge-based odor-gas aerated vertical flow biofilter (Al-OAF) was developed, which aims to removal the pollutants in wastewater and simultaneously to eliminate H2S generated from wastewater treatment facility. Three lab-scale parallel columns were operated in batch model while intermittently aerated with 200 ppm H2S (Al-OAF), air (Al-AF) and unaerated (Al-F, as blank), respectively. The pollutants in wastewater and the effluent H2S concentration from Al-OAF were monitored regularly. Results showed that three columns presented a high removal efficiency (>98%) of total phosphorus (TP) and a completed removal of H2S (100%) in Al-OAF. Al-OAF and Al-AF could enhance the removal efficiency of chemical oxygen demand (COD) of 94.3 ± 3.0, 94.8 ± 1.9%, and total nitrogen (TN) of 86.2 ± 14.2, 91.6 ± 5.4%, respectively. In particular, there was no significant difference regarding the COD, TN removal performances between the “H2S driven” Al-OAF and the “air driven” Al-AF. The H2S removal mechanism lies in the alum sludge ability of H2S adsorption and the reaction by the biofilm in the biofilter. This demonstrates that the novel Al-OAF (aerated with waste gas) would be a promising “wise choice” for intensified biofilter with dual-goals of simultaneous wastewater purification and H2S elimination.

International audience; Cheap alumino-silicate materials such as clay materials and Y zeolite were selected for the catalytic pyrolysis of waste engine oil in a fixed bed reactor. A cheaper route of Y zeolite synthesis involving hydrothermal activation of the raw clay and hydrothermal synthesis was employed. X-ray diffraction technique, scanning electron microscopy, Fourier transform infra-red, and nitrogen desorption method were used to characterize the intermediate phases formed during the hydrothermal treatment of the clay and the synthesized Y zeolite during the hydrothermal processes. The chemical compositions of the liquid phase of catalytic pyrolysis were characterized by gas chromatography coupled with mass spectroscopy (GC–MS). The results revealed that the alkaline concentration strongly influenced the activation of the raw clay to obtain a useful phase for the subsequent synthesis of the Y zeolite. The synthesis improved the surface area from 29 m2/g for the clay to 745 m2/g for the zeolite. The catalytic pyrolysis resulted in diesel fractions of 64.8 and 54.7%, respectively for the Y zeolite and the clay. It was observed that the gasoline fractions increased to 20.5 and 19.1%, respectively for the zeolite and the clay. In the diesel fraction, the zeolite selectively improved the yield of the cyclo-alkanes which are key constituents in terms of the quality of diesel. Y zeolite was successfully derived from a natural clay and tested in the pyrolysis of waste engine oil. The synthesis route provides the opportunity to improve the catalytic property of the natural clay.

Nanocellulose has been established to be one of the most promising green resources of modern times due to its inherent properties and renewability. In this chapter, we present the fundamentals of nanocellulose-based composite materials and their significance in electronics applications. The composites involving various types, including films, papers, and aerogels comprising nanocellulose incorporated with conducting polymers, carbon nanomaterials, metal nanoparticles and oxides, etc. have been discussed. The underlying mechanism for nanocellulose composites to be utilized for electronics device fabrication includes flexible and printed electronics, energy storage and conversion devices, and dielectric and microwave absorbing systems has been systematically presented. The ability of nanocellulose to provide mechanical supports for freestanding flexible and thermally stable electronic devices has been widely exploited. This chapter aims at providing an outline in the fabrication process and significance of nanocellulose composites in the entire electronics.

International audience; The main objective of this work was to analyze the physico-chemicals properties of biochars produced from the steam gasification of different lignocellulosic agrowastes, and determine the suitability of these materials to be used in soil amendment and remediation applications. Steam gasification biochars from three lignocellulosic agrowastes were extensively characterized. Coconut shells (CS), bamboo guadua (BG), and oil palm shells (OPS) were chosen as raw materials, considering their different macromolecular structure and inorganic composition. The biochars composition, morphology, pH, acid neutralization (ANC) and cation exchange (CEC) capacities, as well as their mineral release at different conditions were evaluated and compared. The experimental results showed that the inorganic content and composition of the biochars have a stronger impact on their properties for soil applications, in comparison to their organic composition and morphology. In particular, BG biochar, the sample with the highest mineral content, exhibited the most notable cation exchange (45 cmolc/kg) and acid neutralization capacities (125 cmol H+/kg), together with the greatest release of plant micro and macro-nutrients. In the case of biochars with low mineral content, higher CEC and ANC were most related to the presence of oxygen-containing functional groups in their surface. Considering that agricultural residues come from numerous sources and activities, the presented results usefully contribute to the comprehension of the relationship between the raw biomass characteristics, the physico-chemical properties of steam gasification biochars, and their expected performance in soil applications, opening a new promising valorization pathway for these materials.

International audience; Up-to-date, solar salt (a mixture of 60 mass% NaNO3 and 40 mass% KNO3) is practically the only media for thermal energy storage (TES) in concentrated solar power (CSP). This commercial product’s utilization is limited below 550 °C to avoid an irreversible thermal decomposition. The development of new performing TES materials is decisive for the deployment of CSP technology. Our recent work reported promising results obtained with mono-alkali polyphosphate (M-PO3) as TES materials. These materials can work up to around 900 °C, but their melting point is still high, which is at least 628 °C. In order to lower their melting point, binary and ternary mixtures of alkali polyphosphates are investigated in this work. Dif- ferent mixtures made of two or three alkali polyphosphates were prepared and studied using thermal analysis methods. The most promising mixture found in this work was the ternary Li-Na-K-PO3, which contained 33.3% (mol%) of each alkali metal. This mixture can be used as a liquid TES material in the temperature range of 398 to 900 °C. The results open new prospects for the development of the thermal energy storage field.

International audience; Chitin and chitosan are the second most abundant natural biopolymers in the curst of the earth. These polysaccharide biopolymers have a long linear chain-like structure connected with β-d glucosidic linkage with the functionalizable surface groups. Because of the structural features, these biomaterials exhibit unique physical, chemical, mechanical and optical properties, which contributed to the tunable and outstanding properties such as low density, high porosity, renewability, natural biodegradability, and environmental friendliness, etc. Chitin was synthesized via mechanical, chemical, chemo-mechanical, and eco-friendly biological methods and the deacetylation of the synthesized chitin carried for the preparation of chitosan. With the chemical modification used for the preparation of chitosan, there occurs some minor change in characteristics; however, most of the properties were relatable due to major similarities in the microstructures. The inherent antibacterial, non-toxic, and biodegradable properties with the ease of processibility of both polymer has the potential to become a successful alternative to its synthetic counterparts for energy and environmental applications. However, the poor mechanical and thermal properties in comparison to the conventional alternatives have restricted its widespread applications. This review addresses various areas such as extraction techniques of chitin and synthesis of chitosan, discussion of the common characteristics of both polymers together such as crystallinity, thermal properties, mechanical properties, hydrophilicity, and surface charge. Moreover, this review paper also addresses the common functionalization techniques for both polymer and the use of both unmodified chitin and chitosan along with their derivatives in environmental and energy applications such as air pollution, heavy metal adsorption, dye adsorption, biosensors, EMI shielding, fuel cell, solar cell, lithium-ion batteries, and biofuels.

International audience; This study focusses on reporting a facile one-step synthesis method to fabricate calcium phosphate-microcrystalline cellulose composite with an enhanced surface area. The composite preparation is done using a simple one-step method called co-precipitation method under ambient and 60 °C temperature. The calcium carbonate and orthophosphoric acid are taken, which are the two best known widely available starting materials for the synthesis of calcium phosphate. The sample is collected and taken for the drying process in an oven at 105 °C. The characterizations like XRD, SEM, BET, FTIR, TGA, and DSC of the demonstrated composites are done. From BET analysis, it can be concluded that the surface area of the demonstrated composite enhances substantially after the incorporation of the microcrystalline cellulose.

International audience; Phosphorus (P) is a non-renewable resource, and its recovery and recycling are necessary for meeting future P demands and environmental conservation. Ash and hydrochar from incineration and hydrothermal liquefaction (HTL) of municipal sludge, respectively, represent promising sources for efficient P recovery. The full-scale application of wet-chemical techniques has proven their technical feasibility for P recovery from sludge-derived ash. HTL for sludge treatment has received significant attention for producing biocrude with net-positive energy recovery. P recovery from the solid by-product of sludge HTL, hydrochar, is a critical step in holistic sustainable sludge management. This review aims to guide P recovery from sludge-derived ash and hydrochar by presenting recent advances in wet-chemical extraction and precipitation. By comparing their characteristics, ash and hydrochar derived from municipal sludge exhibit similar feasibilities and challenges for P recovery. Extraction is recognized as the critical step for P recovery. The advantages and disadvantages of various P extraction approaches are provided. Acidic extraction achieves high efficiency (up to 100%) but requires removal of co-extracted heavy metals. Alkaline extraction prevents metals contamination but shows low efficiency (

International audience; In this study, a comprehensive assessment of doped ceramic water filters (doping with hydroxyapatite and alumina) was conducted for potential application in household water treatment. The efficiency/reliability was assessed via statistical data analysis and normal distributions. It was found that the doped ceramic water filters had high porosity (63.25%±0.31% by volume) and a substantial flow rate (14.76±1.43L·h−1). The removal of bacterial contaminants [i.e., log reduction value (LRV)] was also found to be associated with the percentage of porosity. Hence, the doped filters were both efficient and reliable in removing bacterial contaminants (LRV of 4.69±0.19). The removal of chemical/viral contaminants was related to the doping with hydroxyapatite and alumina. Due to kinetics, the removal of viral contaminants also depended on the flow rate of the doped ceramic water filters. This resulted in high efficiency in the removal of viral contaminants (LRV of 3.47±0.35) and high reliability in the removal of chemical contaminants (LRV of 2.26±0.07). The current results suggest that the doped filters are suitable materials for application in household water treatment.

International audience; Pressed plates ceramics made of gross-milled bottom ashes and waste clay, were made using technologies available in the building bricks and tiles industry, to ease production upscaling at low-cost. These sintered ceramics are intended for use as a high-temperature thermal energy storage material. They represent an alternative to the waste-based petrurgic ceramics previously developed for this application. Post-treated incinerator bottom ashes from a commercial incinerator were collected, characterized and processed to form ceramic materials, using clay as a binder. Ashes were milled, dried, and mixed with various amounts of an illitic clay (produced as washing mud by a quartz quarry in proportions from 20 to 70% dry weight) prior to uniaxial pressing (12 × 5 × 1 cm slabs) and firing at various temperatures, ranging from 1050 to 1125 °C. The sintered samples have been characterized in terms of volumic mass, mechanical strength, thermal capacity and thermal conductivity. Their mineral structure has also been studied. The resulting sintered ceramics exhibit relatively high mechanical resistance and low thermal conductivity, along with moderate volumic mass. These properties allow envisioning the use as filler material for thermocline thermal storage systems (structured beds), and could be interesting for further work regarding applications in the construction field (bricks, tiles, pavements…).

International audience; Calcium looping (CaL), based on cyclic carbonation/calcination using lime-based sorbents, is a promising technology for post-combustion CO2 capture. An important obstacle of this technology is the decay of sorbent over multiple cycles. Steam re-activation is a potential approach to improve the sorbent reactivity, however, the effects of both in-situ high-temperature steam (in carbonator or/and calcinator) and ex-situ low-temperature steam (steam hydration in hydrator) are still a matter of debate. Here, a bubbling fluidised bed reactor was used to investigate three steam addition options: steam addition during carbonation stage, or during calcination stage, or intermediate steam hydration after each CaL cycle. A CaO sorbent was tested under varying steam concentrations up to 40 vol.% for 10 CaL cycles (carbonation: 650 °C, calcination: 900 °C). Compared to the dry condition, steam addition during carbonation and intermediate steam hydration were both found effective for CaO re-activation. For the former, the improved sorbent reactivity was mainly attributed to an increased pore volume enhancing the extent of carbonation in kinetic regime; while for the latter, the formation of cracks accelerated the rate of diffusion. Nevertheless, decreasing the hydration temperature was detrimental to sorbent reactivity due to enhanced sintering upon cooling. In case of steam addition during calcination, the sorbent was affected negatively or positively depending on the concentration of steam. At higher steam concentrations (20, 40 vol.%), the sorbent reactivity was significantly decreased due to sintering associated with larger pores and lower surface areas. Overall, steam addition during carbonation was recommended for sorbent re-activation.

International audience; • H 2 S removal from the gas phase using calcium carbonate based solid wastes. • Validation of a triphasic gas/liquid/ solid process at the pilot scale. • Validation of the process with a real gaseous effluent. Keywords: H 2 S removal Calcium carbonate Solid waste Triphasic process Slurry bubble column pilot This work is devoted to the removal of H 2 S from the gas phase using a suspension of calcium carbonate-based residues, recovered from the production of sodium bicarbonate. A 145 L (1.6 m height and 0.34 m internal diameter) slurry bubble column (SBC) reactor was used. The gaseous effluent was bed from the bottom and get out from the top of the column. The suspension (2-20 wt%) was recirculated from the bottom to the top by a pump. This created a counter-current regime between the gas phase (from the bottom to the top) and the liquid phase (from the top to the bottom) which favor the gas/liquid exchange inside the reactor. The influence of different parameters including solid concentration in the suspension (w s), recirculating rate of the suspension (Q R), inlet gas flow rate (Q G), and volume of the suspension, was investigated. The results obtained with this confirmed those at the lab scale, for both synthetic gaseous effluent (H 2 S diluted in compressed air) and real gaseous effluent emitted by the buffer tank of a wastewater treatment plant. This allows validating the technology before its deployment at the large industrial scale for H 2 S removal from the gas phase.

International audience; There is a piqued interest in development of biobased sorbents for water treatment. Here in we reported, the fabrication of mechanically strong nanopapers by mixed dimensional assembly of 1D Cellulose nanofibers and 2D amino functionalized graphene oxide for water treatment. The fabricated amino functionalized GO/ cellulose nanofiber (AMGO-CNF) nanopaper showed superior antibacterial resistance towards Escherichia coli MTCC 1610 and Klebsiella due to the enhanced surface roughness which was confirmed from SEM and AFM studies. The amino group present in the AMGO enhanced the adsorption efficiency of the nanopaper towards methyl orange dye. The fabricated nanopaper showed an adsorption of 11.05 mg/gm 30 mg/L concentration at pH 2. Maximum adsorption was observed at pH 2 which was due to protonation of amine group. Moreover, the fabricated membrane showed excellent hydrolytic stability which can be corroborated to the surface roughness and reduced hydrophilicity. The investigation into the surface chemistries of cellulose nanofibers beyond the adoption of toxic solvents can enhance the economic usefulness of the process and yield a new eco-friendly adsorbent material that is agreeable to adsorbing various toxic pollutants.

International audience; The Fischer‐Tropsch reaction transforms syngas into high added value products, among which liquid fuels. Numerous parameters determine catalytic activity and selectivity towards the most desired hydrocarbons. The performances of cobalt‐based catalysts used in the reaction are known to depend critically on Co particle size and crystallographic phase. Here, we present a comparative study of Co‐based catalysts supported on three carbon supports: multi‐wall carbon nanotubes, carbon nanofibers and a fibrous material. Our results show that, while the selectivity towards C5+ follows the expected tendency with respect to Co particle size, this is not the case for the TOF. These results can be rationalized considering that the amount of H 2 uptake on each catalyst increases with oxygen and defect concentration on the support. The catalyst, on the support presenting many edges and oxygen surface groups, necessary for H 2 spillover, presents the highest activity. Furthermore, the hydrogen spillover contributes to the enhancement of olefin hydrogenation and methane production.

International audience; The aim of this work was to study five (5) selected local raw clay materials from Ghana using different characterization techniques such as Thermogravimetric/Differential Thermal Analysis (TG/DTA), X-ray diffraction (XRD), Fourier Transform Infra-red Spectroscopy (FTIR), Scanning Electron Microscopy equipped with Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Nitrogen Desorption (Brunauer-Emmett-Teller, BET) specific surface area analysis. The clay samples studied are; Nkroful kaolin (NK), Amanfrom kaolin (AK), Ball clay (BC), Akyem Feldspar (AF) and Akwatia silica (AS). SEM and EDX show the morphological features of the five clay samples and also confirm the presence of some dominant elemental compositions such as aluminium and silicon in all the samples. FTIR show that the vibrations spectra in the region around 3,600-3,700 cm-1 and 700-800 cm-1 are due to M-OH groups and that at 900-1000 cm-1 corresponds to Si-O-Si modes. BET analysis gives specific surface area of the clay samples as NK (4.6 m2/g), AK (21.9 m2/g), BC (25.50 m2/g), AS (0.79 m2/g) and AF (0.49 m2/g). X-ray diffraction pattern confirm the presence of quartz as the major reflection in all the samples analysed and only kaolinite reflections appeared in three of the samples (NK, AK and BC). All the kaolinite clays (NK, AK and BC) are suitable starting materials for the fabrication of electroporcelain insulators, catalytic converters and diesel particulate filters.

International audience; The clean and efficient energy production from municipal solid waste (MSW) is highly desirable due to increasing energy demand and environmental concerns. In this study, four incineration- (S1) and gasification-based (S2 with combustion boiler, S3 with gas turbine/combined cycle and S4 with internal combustion engine) MSW treatments were compared using methods of environmental life cycle assessment (LCA) and exergetic life cycle assessment (ELCA). LCA was applied to measure the environmental performances and ELCA was supplemented to reflect the thermodynamics efficiencies. Afterwards, cumulative degree of perfection (CDP) and abatement exergy (AbatCExC) efficiency of the considered systems were also calculated to determine the imperfection and environmental sustainability of the processes. Results showed that gasification-based systems were effective to mitigate the environmental impacts of acidification, nutrient enrichment, and photochemical ozone formation potential, but caused higher global warming impacts. The S3 system exhibited the best performance from both environmental and exergetic perspective, due to its high net efficiency of electricity generation and low exhaust emission into air. Results from ELCA indicated that the rest two gasification-based systems (S2 and S4) were inefficient as compared to MSW direct incineration, mainly due to auxiliary energy consumption for MSW pretreatment and more conversion steps. The CDP and AbatCExC of the systems in descending order was expressed as S3 system > S1 system > S2 system > S4 system.

International audience; Nanocellulose is a sustainable, renewable and eco-friendly nanomaterial with fascinating properties like high strength, low density, high specific surface area, high aspect ratio etc. Nanocellulose surface comprises of large number of hydroxyl groups which facilitates a wide range of surface chemistries and can be tailored for specific applications. These properties of nanocellulose suggests huge potential for various engineering applications. This unique property makes them as a promising candidate for various applications. Now a days, the innovative nanocellulose aerogels have gained substantial attention in the scientific community due to their renewability, good mechanical properties, low density, high porosity, natural biodegradability, and environmental friendliness. These attractive properties facilitate the use of nanocellulose aerogels in various environmental and engineering applications. This article reviews recent attempts to apply nanocellulose aerogels as efficient materials for water purification, air filtration, flame retardancy, oil absorption etc.

International audience; Municipal solid waste (MSW) incinerators require effective flue gas treatment (FGT) to meet stringent environmental regulations. However, this in turn generates additional environmental costs through the impacts of materials and energy used in the treatment – these impacts are currently scarcely known. Therefore, this study uses life cycle assessment to estimate the impacts of different FGT systems typically found in modern MSW incinerators. A total of 12 scenarios are modelled to consider different combinations of the following eight technologies: electrostatic precipitators and fabric filters for removal of particulate matter; dry, semi-dry and wet scrubbers for acid gases; selective non-catalytic and catalytic reduction of nitrogen oxides (NOx); and activated carbon for removal of dioxins and heavy metals. The data are sourced from 90 full-scale incinerators operating in France. The results reveal that a dry system using sodium bicarbonate and selective non-catalytic reduction (SNCR) is the best option for seven out of 18 impacts, including climate change (37.1 kg CO2 eq./t MSW). By contrast, a dry system with calcium hydroxide and selective catalytic reduction (SCR) has the highest impacts in six categories, including climate change (102 kg CO2 eq./t MSW). The wet systems have higher impacts than the dry alternatives, with the semi-dry options being in between. Compared to SNCR, the use of SCR decreases the NOx-related impacts (fine particulate matter formation, terrestrial acidification and photochemical ozone formation) but increases other impacts. For example, the SCR systems have 49–284% greater climate change and 43–150% higher depletion of fossil resources than their SNCR counterparts. Overall, all FGT systems reduce significantly fine particulate matter formation (by 81–88%), photochemical ozone formation (76–90%) and terrestrial acidification (83–90%). However, they also cause 14 other impacts which would not be generated if the flue gas was left untreated, thus creating additional environmental costs. These include climate change, resource depletion and human and ecotoxicities. Therefore, these trade-offs should be considered carefully to minimise the unintended environmental consequences of flue gas treatment from incineration of MSW.

International audience; Wood waste containing halogenated compounds such as polyvinyl chloride (PVC) is in abundant supply, although the pyrolysis of such waste feedstock for energy production may cause corrosion and environmental problems due to the release of HCl gas. Hence, there is a need to understand the pyrolysis behaviour of chlorine-contaminated wood in order to develop methods that minimise the impact of chloride species on pyrolysis equipment and product quality. In literature, few studies exist on the kinetic analysis of wood and PVC co-pyrolysis. The existing models assume a single-step reaction with an n-order reaction mechanism for the entire process, which may lead to large errors in the kinetic parameters estimated. Therefore, in this paper, we develop and validate a multi-step kinetic model that predicts the pyrolysis behaviour and reaction mechanism of poplar wood (PW) pellet with different contents of PVC (0, 1, 5, 10, 100 wt%). Using data from thermogravimetric analysis of the pellets at heating rates of 5, 10 and 20 °C/min, we determined the apparent kinetic parameters by combining Fraser-Suzuki deconvolution, isoconversional methods and master plot procedures. Our model fitted the experimental data well with a deviation of less than 4.5%. Our results show that the addition of 1 wt% PVC to PW decreases the activation energy of hemicellulose and cellulose pyrolysis in PW from 136.3 to 101.6 kJ/mol and from 216.7 to 108.2 kJ/mol, respectively. This demonstrates the importance of acid hydrolysis reactions between the cellulosic fibres of PW and HCl released from PVC dehydrochlorination. Furthermore, we found that a nucleation and growth mechanism best represents the rate-limiting interactions between PVC and PW, which we linked to the formation of metal chloride crystals from acid-base reactions between HCl and PW minerals. Our kinetic model is an improvement of current models for the co-pyrolysis of wood and PVC, and can be readily used in a reactor-scale model of a pyrolyser or gasifier due to its relative simplicity.

In this paper, gas permeability studies were performed on materials based on natural rubber/acrylonitrile butadiene rubber blends and nanoclay incorporated blend systems. The properties of natural rubber (NR)/nitrile rubber (NBR)/nanoclay nanocomposites, with a particular focus on gas permeability, are presented. The measurements of the barrier properties were assessed using two different gases—O2 and CO2—by taking in account the blend composition, the filler loading and the nature of the gas molecules. The obtained data showed that the permeability of gas transport was strongly affected by: (i) the blend composition—it was observed that the increase in acrylonitrile butadiene rubber component considerably decreased the permeability; (ii) the nature of the gas—the permeation of CO2 was higher than O2; (iii) the nanoclay loading—it was found that the permeability decreased with the incorporation of nanoclay. The localization of nanoclay in the blend system also played a major role in determining the gas permeability. The permeability of the systems was correlated with blend morphology and dispersion of the nanoclay platelets in the polymer blend.

International audience; Although work has been done to understand the sintering behavior and properties of Municipal Waste Incinerator Bottom Ashes to produce sintered (Bethanis et al. in Ceram Int 28:881–886, 2002; Cheeseman et al. in Resour Conserv Recycl 43:147–162, 2005; Bourtsalas et al. in Waste Manag 45:217–225, 2014; Taurino et al. in J Eur. Ceram Soc 37:323–331, 2017) or sinter-crystallized (Schabbach et al. in J Non Cryst Solids 357:10–17, 2011; Barbieri et al. in J Non Cryst Solids 354:521–528, 2008) ceramics, most of the trials reported in the literature focuses on the use of extensively milled bottom ashes powders (particle size around 1–50 µm), using processes that might not be easily transferable to industrial production at reasonable cost, and producing small cylinders with uniaxial compression technique on powders. This paper summarizes the development process of an extruded ceramic material made of gross-milled bottom ashes and waste clay, designed to be easily mass-produced using production capacities available in the building bricks industry, to be used as a high-temperature thermal energy storage material, which represents an alternative to the petrurgic ceramic previously developed for this application (Py et al. in J Sol Energy Eng 133:031008, 2011; Kere et al. in Int Conf Eng Waste Biomass Valoris, Porto, 2012; Py et al. in Stockage de l’ énergie: énergie thermique, stockage thermique haute température). Post-treated incinerator bottom ashes from a commercial incinerator has been collected, characterized and processed to form ceramic materials, using clay as a binder. Ashes were milled, dried, and mixed with various amounts of an illitic clay (produced as washing mud by a quartz quarry) prior to extrusion (cylindrical pellet) and firing at different temperatures, ranging from 1100 to 1120 °C. The sintered samples have been characterized in terms of density, mechanical strength, thermal capacity and thermal conductivity. Their mineral structure has also been studied. This work follows a study on the feasibility about the production of MWIBA based slabs with uniaxial compaction, and can be seen as an improvement regarding the shaping of the green bodies, more compatible with thermocline thermal energy storage process. The resulting sintered ceramics exhibit interesting properties such as relatively high mechanical resistance and low thermal conductivity, along with moderate density. These properties allow envisioning the use as filler material for thermocline thermal storage systems, especially considering the simplicity of the production process, relying on dry gross milling (jaw-mill), and firing at a temperature reachable within the building bricks and tiles industry. Production of adequate pieces to be used as thermal storage media seems however more relevant, the small size limiting the impact of sintering heterogeneities (formation of black bodies due to high content in fluxing agents like sodium and potassium).

International audience; Hydroxyapatite [HAP, (Ca10(PO4)6(OH)2)] is an emerging catalytic support possessing exciting features such as high thermal and mechanical strength, chemically stable with low water solubility along with tunable porosity and acid-basic character. Despite of these interesting characteristics, it has not yet been investigated in Fischer-Tropsch (FT) synthesis. Herein, for the first time, HAP-supported cobalt catalysts (Co/HAP) prepared by conventional incipient wetness impregnation method were examined in the FT synthesis process. The catalytic performance of these catalysts was compared with alumina-supported cobalt catalysts (Co/Alumina). HAP support was found to exhibit considerably less acid-site density, consequently, reducing detrimental interactions of the support with cobalt precursors leading to hardly reducible Co species that are generally observed with its alumina counterpart. Co/HAP catalysts exhibit relatively larger Co particle sizes (~9 nm versus ~6 nm, as observed from TEM analysis) and better Co reducibility when compared to its counterparts on alumina. FT synthesis at 20 bar, 220 °C and H2/CO = 2.1 showed that the CO conversion was higher on the catalysts (10 wt% Co loading) using HAP as a support material when compared to alumina. Under different testing conditions (220 or 230 °C) using the Co/HAP catalyst, the C5+ selectivity was in the range of 82–88%, whereas the methane selectivity was about ~10%.

International audience; Ni-based catalysts were prepared using two hydroxyapatites (Ca-HA1, SBET = 7 m2/g and Ca-HA2, SBET = 60 m2/g) with different physico-chemical properties. The objective of the study was to evaluate the performance of these two materials as promising supports for dry reforming reaction (DRM) as well as to investigate the influence of different process parameters, such as temperature, pressure, time and catalyst pretreatment on the performance of these two catalysts. Thermodynamic calculations were performed to determine the conditions that would limit solid carbon deposit and favor the reactants conversion. Then, an experimental parametric study was carried out to investigate the impact of the temperature, pressure, catalyst pretreatment and support thermal treatment on the catalysts performance. The results showed that the catalyst pretreatment allowed the reduction of the nickel particles in a higher extent, which resulted in better catalytic performance when compared to the catalysts without pretreatment. High temperatures around 700 °C and low pressures around 1.6 bar were required to attain high CH4 and CO2 conversions around 70–80% as well as high H2 and CO selectivity around 90% for 90 h of time on stream. In all cases, Ni/Ca-HA2 catalyst presented better catalytic performance than Ni/Ca-HA1 due to the presence of smaller nickel particles (10–20 nm), stronger basicity, higher density of basic sites (0.23 mmol g−1) as well as higher specific surface area (SBET = 60 m2/g) of the Ca-HA2 support. Ni/Ca-HA2 catalyst was highly active (initial methane conversion: 75%) and relatively stable during 90 h of TOS and its catalytic behavior was comparable with the performance of Ni-based catalysts prepared with conventional supports reported in the literature.

International audience; In this work, Mg-doped Al2O3 supports were used for the preparation of Ni catalysts, which were then tested in dry reforming of methane reaction (DRM) for syngas production. The influence of MgO content (0–70 wt%) on the basicity of the catalysts as well as on the formation of a NiO-MgO solid solution was investigated and linked to the catalytic performance of the catalysts. The catalyst containing high amount of Mg (Ni/70MgAl) showed the best performance with negligible deactivation rate over 50 h of time on stream (TOS). The presence of strong basic sites in this catalyst was important to adsorb carbon dioxide (CO2), to gasify the coke deposit and to increase the syngas production. Also, the presence of a NiO-MgO solid solution led to strong metal-support interaction, which limited the sintering of nickel particles. The quantification of the water formed during the reaction showed that its formation was crucial for the elimination of the coke deposits as well as to increase the syngas production.

Municipal solid waste (MSW) pyrolysis and gasification are in development, stimulated by a more sustainable waste-to-energy (WtE) option. Since comprehensive comparisons of the existing WtE technologies are fairly rare, this study aims to conduct a life cycle assessment (LCA) using two sets of data: theoretical analysis, and case studies of large-scale commercial plants. Seven systems involving thermal conversion (pyrolysis, gasification, incineration) and energy utilization (steam cycle, gas turbine/combined cycle, internal combustion engine) are modeled. Theoretical analysis results show that pyrolysis and gasification, in particular coupled with a gas turbine/combined cycle, have the potential to lessen the environmental loadings. The benefits derive from an improved energy efficiency leading to less fossil-based energy consumption, and the reduced process emissions by syngas combustion. Comparison among the four operating plants (incineration, pyrolysis, gasification, gasification-melting) confirms a preferable performance of the gasification plant attributed to syngas cleaning. The modern incineration is superior over pyrolysis and gasification-melting at present, due to the effectiveness of modern flue gas cleaning, use of combined heat and power (CHP) cycle, and ash recycling. The sensitivity analysis highlights a crucial role of the plant efficiency and pyrolysis char land utilization. The study indicates that the heterogeneity of MSW and syngas purification technologies are the most relevant impediments for the current pyrolysis/gasification-based WtE. Potential development should incorporate into all process aspects to boost the energy efficiency, improve incoming waste quality, and achieve efficient residues management.

International audience; Syngas production via the pyro-gasification of waste biomass is a promising means of managing waste while producing renewable fuel. However, such waste may contain a significant level of impurities such as chlorine, which may result in hydrogen chloride (HCl) being formed in the syngas produced. The presence of HCl gas may increase the risk of corrosion and may be harmful to health and to the environment. Consequently, stricter limits on HCl concentration in syngas are being imposed by environmental regulations and syngas end-use specifications, which is driving the search and development of more efficient and cost-effective methods of eliminating HCl. One such method is dry adsorption using inorganic sorbents. In literature, the majority of sorbents studied are based on commercialised products, and thus, there lack studies on the use of waste-derived sorbents for treating HCl in syngas. Therefore, this paper presents an experimental study on the adsorption potential of the solid waste sorbent, CCW-S, which is compared to that of the commercial sorbent, Bicar. Various physico-chemical analyses were performed on the sorbents before and after the tests, including ICP, FTIR, XRD and TEM-EDX. The first set of adsorption tests were performed using a gas mixture of 500 ppm HCl in nitrogen (HCl/N2) at ambient conditions (25 °C, 1 atm). The results revealed that Bicar was the better performing sorbent with an average breakthrough time of 66 h and a HCl adsorption capacity of 27 wt%, whereas the performance of CCW-S was lower (7.8 h and 4 wt%). Furthermore, TEM-EDX images of CCW-S particles show the participation of the impurities—Al, Fe, and Mg—in HCl capture. When the second set of adsorption tests were conducted with a simulated HCl/syngas atmosphere, a significant decrease in sorbent performance was observed, which showcases inhibitory interactions occurring between syngas and the sorbents, in relation to HCl adsorption. The results of this preliminary investigation reveal a promising opportunity to valorize industrial residues as cheap and efficient sorbents for the removal of HCl in syngas. This will enable a wider market penetrating of waste-derived syngas, while meeting the quality requirements of increasingly strict environmental regulations and end-use devices.

International audience; The primary cause of anaerobic digester failure includes accumulation of inhibitory substances and intermediate products such as volatile fatty acids (VFAs), free ammonia (NH3 +), and ammonium (NH4 +). They (except VFAs) are however required as essential nutrients for bacteria growth. The current study specifically investigated the effect of oil content on the biogas production and the stability of anaerobic digestion of food waste. Two lab scale reactors were designed with different organic loading rates and feeding adjustment of used oil addition to testing the effects of lipids on biodegradation and biogas production. The results indicate that, at 2.0 g VS L−1 d−1, the addition of oil (5% v/v), caused the reactor failure, whereas, at 4.0 g VS L−1 d−1, the reactor remained stable for 10 days before the accumulation of VFAs, which resulted in low pH, and thus reduced the biogas and methane production. The addition of NaOH to reactivate the reactors can only improve pH, alkalinity and negatively increased viscosity, but there was no significant effect on biogas production and VFAs concentration. An effective solution to reactivate the reactors was achieved by recirculating 50% of both reactor’s effluent back to the reactors. This resulted in biogas recovery and stable process performance of the reactors. Surprisingly, NH4 +–N remained stable (1400 mg L−1) throughout the period, far less than the critical concentration of 3000 mg L−1. On the contrary, the low NH4 +–N couldn’t contribute to buffering the reactor’s high VFA concentration during the unstable period, thereby raising new questions on its roles in anaerobic digestion process.

International audience; To identify the performance and mechanism of variant molten salts during biomass pyrolysis in molten salt, the thermogravimetric and differential scanning calorimetry (TG-DSC) analyzer, fixed-bed reactor and thermodynamic equilibrium simulation were applied to study the thermal melting characteristics and stability of molten salt as well as the selectivity for biomass pyrolysis products. The KCl-ZnCl2 is appropriate for the preparation of H2-rich gas and the carbon material with abundant mesoporous structure due to its activation effect. At 850 °C, the pyrolysis gas obtained from KCl-ZnCl2 contained 42.22 vol% H2 with the H2/CO ratio reaching 1.69. The carbonates demonstrated excellent improvement for the gas composition of biomass pyrolysis products, with 75.43 vol% and 70.52 vol% syngas (H2 + CO) collected from the Li2CO3-K2CO3 and Li2CO3-Na2CO3-K2CO3 pyrolysis systems at 850 °C respectively. With the presence of carbonates, the bio-oil and char prepared by biomass pyrolysis also achieved better quality. The thermodynamic simulation revealed the shifting (formation of Li2O) of molten salt composition during biomass pyrolysis. The interaction between Li2CO3 and char under high temperature explained the high yield of CO in pyrolysis gas products, also resulted in the consumption of salts and limited the sustainable use of the molten salt pyrolysis system.

Levulinates could be used as oxygenated fuel additives or as blending components in biodiesel. In this work, a metallic salt was used for the direct conversion of biomass, ie. (softwood bark), to produce methyl levulinate (ML) and levulinic acid (LA). The experimental data were analyzed through using a response surface methodology (RSM) as well as a central composite design (CCD). Three dependent responses (ML yield, LA yield, and residue production) were studied to determine the optimum combination of the four factors. The total yield of levulinates was 62% at the optimum process parameters, including catalyst concentration (0.067 mol/L), reaction time (5.67 h), and softwood bark concentration (2.5 wt%) at 200 °C. Finally, the results showed that Al2(SO4)3 allowed the production of levulinates probably in light of its good BrOnsted/Lewis acidity while also allowing t to decrease the corrosion inside the reactor (as compared to homogeneous acids such as H2SO4). This shows that the use of these metal salts for this specific application could positively affect the production costs of levulinates (either CAPEX or OPEX) at larger scale.

Graphical abstract, Highlights • The existing DWTPs are able to reduce the coronavirus, to date, the drinking water is safe. • The coronaviruses shed in the faeces and urine of infected individuals and then entered wastewater. • SARS-CoV-2 has been detected in a few standard WWTPs and they seem to be enough for removing the virus. • Wastewater monitoring could be a strategic tool for the epidemy evolution in communities. • Intensive studies for SARS-CoV-2 behavior in water and wastewater treatment are highly desirable., By 17 October 2020, the severe acute respiratory syndrome coronavirus (SARS-CoV-2) has caused confirmed infection of more than 39,000,000 people in 217 countries and territories globally and still continues to grow. As environmental professionals, understanding how SARS-CoV-2 can be transmitted via water and air environment is a concern. We have to be ready for focusing our attention to the prompt diagnosis and potential infection control procedures of the virus in integrated water and air system. This paper reviews the state-of-the-art information from available sources of published papers, newsletters and large number of scientific websites aimed to provide a comprehensive profile on the transmission characteristics of the coronaviruses in water, sludge, and air environment, especially the water and wastewater treatment systems. The review also focused on proposing the possible curb strategies to monitor and eventually cut off the coronaviruses under the authors’ knowledge and understanding.