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L'elevata variabilità genetica è utile per conservare caratteri di importanza ecologica, come bassa esigenza di freddo, adattabilità a fattori ambientali limitanti e resustenza a stress biotici

SSCI-VIDE+ATARI+AAU; International audience; Mesoporous carbon (MC) and two types of N-containing mesoporous carbons (N-MC and C3N4-MC) were prepared from cost-effective materials and used in two different applications: hydrogen storage and pollutants capture. They were used for hydrogen storage both at 77 K and room temperature (RT). The mesoporous structure was confirmed by N2 adsorption isotherm at 77 K, and the characterization of the bulk and surface properties performed by ICP analysis, TEM, XRD, and XPS. The maximum hydrogen uptakes were found on N-MC (1.1 wt% of hydrogen) at 100 bar and RT and on MC (3.07 wt% of hydrogen) at 40 bar and 77 K. Due to the extremely low content of micropores, a clear relation between the presence of N atoms and the higher hydrogen storage at room temperature was observed. To the other hand, at liquid nitrogen temperature, the differences in surface area and micropore volume confirmed to be the most important factors on hydrogen storage ability [1].The same porous carbon materals have been used as adsorbents of liquid pollutants. In comparison to classical activated carbon materials with micropores (

SSCI-VIDE+ATARI+ALI:VFO:AAU; International audience; IntroductionAn heterogeneous catalytic reaction proceeds according to the following stages: adsorption of the reactant on the surface of the catalyst, reaction on the surface, and desorption of the products. All these steps involve the surface active sites, whose acid/base properties are important factors that determine the catalytic activity and the industrial applications. Relative acid strengths of solid catalysts depend markedly on whether a solvent is present, on the nature of the solvent, and may vary as the medium in which the acidity is measured [1,2]. Moreover, when the heterogeneous catalytic reaction occurs in water, the catalyst has to maintain its acidity even in this protic and polar solvent which is known to quench the acidity of many good solid acids. Therefore novel solid acids, with water-tolerant properties are requested for catalytic processes of biomass exploitation. The key role of surface acidity in clean catalytic processes for the production of biofuel precursors such as 5-HMF has been investigated by adsorption microcalorimetry and related to the dehydration of fructose or to cellobiose conversion on a large variety of acidic, basic and amphoteric catalysts[3,4] . The oxidative coupling of methanol and ethanol for acrolein production has been also studied and related to the acid/base properties of catalysts.Materials and Methods Investigated catalysts were either acidic such as zeolites Y and MFI, resins (Amberlite, Nafion), activated carbon, niobium oxide and niobium phosphate or amphoteric (meso-structured alumino-silicate, silica-aluminas with alumina contents varying from 13 to 95wt%, hydrotalcites or mainly basic such as magnesia, hydroxyapatite and lanthanum oxide. In gas phase, the acid/base properties were measured by adsorption calorimetry of ammonia and sulfur dioxide respectively, using a heat flow calorimeter (C80 from Setaram) linked to a volumetric line allowing the introduction of small doses of probe molecule. Titration calorimetry (Titrys from Setaram), a very powerful tool to determine the strength and number of the sites (when coupling with UV-Vis spectrometry) in liquid media has been used with phenylethylamine and benzoic acid as basic and acidic probe molecules respectively.Results and discussionThe plot of adsorption heats as a function of the probe molecule uptake provides significant information about the sites strength distribution on the catalyst surface, but also on the nature and the strengths of solvate-solvent and sorbate-solvent interactions and on the degree of energetic heterogeneity of the solid surfaces. The saturation uptakes obtained from adsorption measurements give the information about the number of accessible surface sites.Special attention was given to the correlations between catalytic activity and surface acid–base properties, which are essential to the mechanism of the reaction. Figure 1 shows how the selectivity to 5-HMF is varying with increasing the density of acid sites on the surface of the catalysts tested in the fructose dehydration reaction.Concerning the impact of the acid-base properties on the selectivity towards acrolein starting from a mixture of methanol and ethanol, investigated in oxidizing conditions, it has been demonstrated that a balanced ratio of basic to acidic sites improves significantly the acrolein yield[5]. Figure 1. Selectivity in 5-HMF (after 6 h of fructose conversion reaction) as a function of the number of strong surface acid sites of various catalysts, measured in aqueous phase. On amphoteric samples the results of catalytic test performed showed that the selectivity in the reaction is largely governed by the balance between acidic and basic active sites, but also by the ratio of Lewis to Brønsted acid sites. Acknowledgments : The authors acknowledge the Agence de l'Environnement et de la Maîtrise de l'Energie (ADEME) for funding (Bioma+ project)References :1.Gervasini A., Auroux A., Thermochimica Acta, 8, (2013), 567 2.Kourieh R., Bennici S., Marzo M., Gervasini A., and Auroux A., Catalysis Communications, 19, (2012), 1193.Kourieh R., Rakic V., Bennici S., and Auroux A., Catalysis Communications, 1, (2013), 54.Carniti P., Gervasini A., Biella S., Auroux A., Chemistry of Materials, 17, (2005), 61285.Lilić A., Bennici S., Devaux JF., Dubois JL., Auroux A., ChemSusChem, DOI: 10.1002/cssc.201700230

SSCI-VIDE+ATARI+AJH:AAU:SBE; International audience; The water vapor sorption capacity and corresponding generated heat amount are the most important properties for adsorbents in thermochemical heat storage systems. In order to understand the adsorption/desorption behavior of three nanoporous molecular sieves such as 5A, mordenite and natural clinoptilolite (with different structures, Si/Al ratios and balancing cations), the pure zeolites and their composites (obtained by depositing NaOH onto the molecular sieves) were characterized in their structural and surface properties by using appropriate techniques (N-2 adsorption isotherms at -196 degrees C, XRD and (MAS) NMR). The adsorption of water was performed using a Setaram TG-DSC 111 apparatus. Three successive cycles of hydration (at 20 degrees C)/dehydration (at 150 degrees C) were carried out to check the stability of the system in conditions close to those used in adsorption heat pumps. The measured heats of dehydration vary in the 183-614kJkg(sample)(-1) range for the various samples that present also different water vapor sorption capacities (from approximate to 0.08 to approximate to 0.14 kg(H2O) kg(sample)(-1)). The water adsorption/desorption behavior of the zeolites was mainly related to the porous structure and to the Si/Al ratio, that drive the affinity of zeolite to water. The experimental results showed that the impregnation of the three kinds of nanoporous zeolites with different amounts of sodium hydroxide negatively affects the sorption characteristics of the composites. The blockage of zeolite pores (that limits the access to water molecules), the slight amorphization of the zeolite structure and the formation of carbonates are some of the phenomena identified to influence the water sorption onto NaOH-containing composites. Copyright (c) 2016 John Wiley

SSCI-VIDE+ATARI+AAU; International audience; Solid acid catalysts are among the most used in industrial chemical processes. In view of their use in biorefinery processes, a typical property that they have to possess is tolerance to water and polar-protic liquids. Niobium oxophosphate (NbP) is a recognized water-tolerant solid acid with high ratio of Brønsted (BAS) to Lewis (LAS) acid sites, used in various reactions. The prospect of extending its use in other acid demanding reactions has stimulated this study, in which the NbP surface has been modified by acid treatment to obtain a new acid sample (NbP1). Measurements of surface acidity in different liquids have been performed by titration calorimetry complemented with volumetric experiments, using 2-phenylethylamine basic probe. The catalytic performances have been measured in hydrolysis reactions using cellobiose and inulin as substrates. Both are interesting reactions for biomass valorization, giving rise to monosaccharides and high added value chemicals.1. ScopeSolid acid catalysts are used in several bio refinery reactions that take place in liquid or vapor water or alcohol solutions. The well-known niobium oxophosphate acid catalyst (NbP) has been used with success in several reactions that deal with biomass valorization, thanks to water-tolerant acid properties of its LAS and BAS sites.1 In this study, NbP and a sample modified by acid treatment (NbP1) have been characterized, in particular in their acid properties (nature, strength, and strength distribution of the sites) in various liquids. The good catalytic activity in two reactions of carbohydrates hydrolysis (cellobiose and inulin), studied under mild conditions (up to 130°C), proved the potentiality that these solid acid samples can have in biomass valorization reactions as they both maintained good acidity in polar-protic liquids.2. Results and discussionHydrolysis reactions of biomass carbohydrates (cellulose, inulin, etc.) have gained some importance due to the possibility to obtain monosaccharides, that can be used as starting material to synthesize important chemicals (like 5-hydroxylmethyl-furfural, HMF). In this scope, it is of utmost importance to select suitable catalyst samples by controlling their water-tolerant acid properties. The presence of both LAS and BAS at the surface of NbP and NbP1 (prepared by acid treatment, 1 M HCl, from NbP) as well as the maintenance of the acid properties in water have been observed with FT-IR (Biorad, FTS-60A) experiments of pyridine adsorption/desorption.1 The acid strength of the surface sites has been measured with calorimetric experiments (Calvet Titrys calorimeter) in different liquids, with apolar-aprotic (cyclohexane), and polar-protic (isopropanol, water, and their mixtures) characteristics, by using 2-phenylethylamine (PEA) as basic probe. Volumetric experiments, through collection of PEA adsorption isotherms, allowed the determination of the amount of acid sites in various liquids and liquid mixtures. It was then possible to compare the differential heats of PEA adsorption in the studied liquids for NbP and NbP1 samples that showed different strength distributions of the acid sites.It is known that relative acid strengths of surfaces depend on whether a solvent is present, on the nature of the solvent, and may vary as the medium in which the acidity is measured is changing. The results obtained from microcalorimetry experiments are expressed Fig. 1 in the form of integral heats values vs. amounts of PEA probe added over NbP and NbP1. Therefore, the intrinsic and effective acidities can be compared.Figure 1. Integral heat curves vs. PEA addition over NbP and NbP1 in the calorimetric cell.Whatever the polar solvent, the effective acidities are always higher for NbP than NbP1. The differentdistribution of LAS and BAS acid sites in the two samples is more clearly evidenced in isopropanol. Innearly apolar and aprotic solvent like cyclohexane, the intrinsic acidity of both samples is very similar.The different acid strengths in polar-protic liquids manifested by NbP and NbP1 can be justified by amodification of the nature, LAS and/or BAS, of their surface acid sites. Spectroscopic (FT-IR) analyses ofpyridine vapour adsorption/desorption showed LAS/BAS ratios of 1.69 and 1.33 for NbP and NbP1,respectively. When the LAS/BAS ratio was measured in the presence of water, the values were 1.30 and 2.35for NbP and NbP1, respectively. This indicated that on both the samples, LAS were tolerant to water, whileNbP1 possessed very weakly acidic BAS that could not be titrated in water.The catalytic tests of hydrolysis of cellobiose (constituted by glucose units linked by ,1-4 glycosidic bonds)and of inulin (polymer chain of fructose residues linked by -1,2 bonds and terminated with sucrose residue),realized under mild conditions (80-130°C) in liquid water, confirmed the good acidity of both the samples(Table 1). In cellobiose hydrolysis reaction, carried out at higher temperature (up to 130°C) than inulinhydrolysis, HMF was observed among the products, with glucose and low amount of fructose. In thisreaction both BAS and LAS work to form HMF. Low-temperature hydrolysis (up to 90°C) of inulin gavefructose with very high selectivity. In this reaction, the higher activity of NbP than NbP1 is justified by thehigher amount of water-tolerant BAS on NbP surface (Fig.1).Table 1. Calculated kinetic constants and activation parameters of the two hydrolysis reactions on NbP and NbP1.cellobiose hydrolysis inulin hydrolysissample k(120°C) / h-1 Ea / kJ·mol-1 ln A k(90°C) / h-1 Ea / kJ·mol-1 ln ANbP 0.76 115 35 0.96 144 11NbP1 0.70 166 50 0.51 150 49Catalyst-stability in water was checked by recycling experiments. They showed some problems of catalyststability that was higher for NbP than for NbP1. The better stability of NbP1 could be associated with lowerdeactivation, by insoluble humins deposited on the catalyst surface, due to its lower acid-site density.3. ConclusionsThe importance of measuring the effective acidity of catalysts in given liquids by mimicking the reactionconditions has been emphasized by working with two acid catalysts based on niobium oxophosphate, studiedin two reactions of biomass valorization. We have shown that it is then possible to suitably select activecatalysts for given reactions by this approach.References1. P. Carniti, A. Gervasini, F. Bossola, V. Dal Santo, App. Catal. B 2016, 193, 93-102.

SSCI-VIDE+ATARI+AAU:SBE:; International audience; The water vapor sorption capacity and corresponding generated heat amount are the most important properties for adsorbents in thermochemical heat storage systems [1,2]. In order to understand the adsorption/desorption behavior of three nanoporous molecular sieves such as 5A, mordenite and natural clinoptilolite (with different structures, Si/Al ratios and balancing cations), the pure zeolites and their composites (containing 5 and 10wt% of NaOH) were characterized in their structural and surface properties by using appropriate techniques (N2 adsorption isotherms at -196°C, and XRD, and (MAS) NMR). The adsorption of water was performed using a Setaram TG-DSC 111 apparatus. Three successive cycles of hydration (at 20°C) / dehydration (at 150 °C) were carried out to check the stability of the system in conditions close to those used in adsorption heat pumps.The measured heats of dehydration vary in the 183-614 kJ kg-1sample range for the various samples that present also different water vapor sorption capacities (from 0.08 to 0.14 kgH2O kg-1sample). The water adsorption/desorption behavior of the zeolites was related to the porous structure and to the Si/Al ratio. These features characterize the affinity of zeolite to water. The experimental results showed that the impregnation of the three kinds of nanoporous zeolites with different amounts of sodium hydroxide affects the sorption characteristics of the composites due to the possible blockage of zeolite pores that limits the access of water molecules.References1.Whiting G, Grondin D, Stosic D, Bennici S, Auroux A. Zeolite-MgCl2 composites as potential long-term heat storage materials: Influence of zeolite properties on heats of water sorption. Solar Energy Materials and Solar Cells 2014; 128: 289-295.2.Jabbari-Hichri A, Bennici S, Auroux A. Water sorption heats on silica-alumina-based composites for interseasonal heat storage. Journal of Thermal Analysis and Calorimetry 2014; 118: 1111-1118.PEquipeDeRecherche

SSCI-VIDE+ATARI+ALI:SBE:AAU; International audience; n the third decade of the past century, acrolein, a key intermediate in the synthesis of two important commodity chemicals, namely acrylic acid and methionine, was industrially produced by aldolisation of acetaldehyde and formaldehyde. Later, another synthetic way based on propylene oxidation was applied and largely studied. More recently, due to the raw materials diversification and the need to decrease the greenhouse gas emissions, new processes starting from renewable feedstock have been considered [1,2].With the aim of minimizing the investment on the existing plants, the oxidation of biosourced alcohols is a promising way to produce acrolein when compared to glycerol dehydration. In this work, the oxidation of a mixture of methanol and ethanol to formaldehyde and acetaldehyde on FeMoOx and simultaneous aldol-condensation and dehydration to acrolein on Na,K,Ca,Mg/SiO2, was carried out; while most of research works published previously, were considering each reaction individually.In the present study, a series of oxide catalysts obtained by deposition of basic oxides (Na2O, K2O, MgO, CaO) on a silica support has been considered in the oxidative coupling of alcohols to produce acrolein. The addition of different guest oxides of the first and second group of the periodic table, allowed to tune the acidity and basicity of the catalyst surface.The basic and acidic properties of the catalysts have been investigated respectively by sulphur dioxide and ammonia adsorption calorimetry in order to obtain the number, strength and strength distribution of the active sites. Finally, the catalytic reaction has been performed with the aim to verify how in oxidizing conditions the acid/base properties can impact the activity and selectivity towards acrolein.Good performances were obtained for Na/SiO2 catalyst with 25% acrolein yield and 10% CO+CO2 yield. K/SiO2 and Ca/SiO2 showed the lower acrolein production; they promoted side oxidation reactions that overoxidized acrolein (or reactants) into CO and CO2, due to the presence of oxygen. At 5000 h-1 GHSV and a temperature of 280 °C for K/SiO2 and of 320 °C for Ca/SiO2, the CO+CO2 yields were already higher than 10 mol%, thus limiting the possibility to further increase the reaction temperature to enhance acetaldehyde conversion and acrolein selectivity.Mg/SiO2 presented the best results (at 320 °C and 5000 h-1 GHSV) with 29% and 38% of acrolein yield and selectivity, respectively, and a CO+CO2 yield of 7% (see Figure). The presence of both acid and basic sites seems to increase the selectivity towards acrolein.References1. JL Dubois, C. Duquenne, W. Hölderich, J Kervennal, Patent US7655818 BB, Arkema France,20062. D. Stosic, S. Bennici, J.-L. Couturier, J.-L. Dubois, A. Auroux, Catal. Commun. 17 (2012) 23-28.Acknowledgements: the present research has received support from ADEME BIOMA+.

SSCI-VIDE+ATARI+AAU; International audience; n the third decade of the past century, acrolein was industrially produced by aldolisation of acetaldehyde and formaldehyde. Later, another synthetic ways based on propylene oxidation was applied and largely studied. More recently, due to the willing of diversifying the raw materials, the need to decrease the greenhouse gas emissions, and in order to optimize the supply of the reactants; new synthetic processes starting from renewable feedstock have been considered [1,2]. With the aim to find renewable materials easy to transform into acrolein, minimizing the investment on the existing plants, the oxidation of biosourced alcohols is a promising way. In this process, the oxidation of methanol and ethanol to formaldehyde and acetaldehyde and the aldol-condensation and dehydration of the two aldehydes to acrolein, are carried out simultaneously, contrarily to most of research works published up to now.In the present study, a series of oxide catalysts obtained by deposition of basic oxides (Na2O, K2O, MgO, CaO) on a silica support has been considered in the cross-condensation of aldehyde and formaldehyde to produce acrolein. The addition of different guest oxides of the first and second group of the periodic table, allowed to tune the acidity and basicity of the catalyst surface. The basic and acidic properties of the catalysts have been investigated by adsorption calorimetry in order to obtain the concentration, strength and strength distribution of the active sites. Finally, the catalytic reaction has been performed in presence of oxygen with the aim to verify how in oxidizing conditions the acid/base properties can impact the activity and selectivity towards acrolein.Mg-Si presented the best results (at 320 °C and 5000 h-1 GHSV) with 29% and 38% of acrolein yield and selectivity, respectively, at a CO+CO2 yield of 7% (in the Figure). Good performances were obtained also for Na-Si catalyst with 25% acrolein yield and 10% CO+CO2 yield. K-Si and Ca-Si showed the lower acrolein production; they promoted side oxidation reactions that transform acrolein (or reactants) into CO and CO2, due to the presence of oxygen. At 5000 h-1 GHSV and a temperature of 280 °C for K-Si and of 320 °C for Ca-Si, the CO+CO2 yields were already higher than 10 mol%, thus limiting the possibility to further increase the reaction temperature to enhance acetaldehyde conversion and acrolein selectivity.References1.JL Dubois, C. Duquenne, W. Hölderich, J Kervennal, Patent US7655818 BB, Arkema France,20062.D. Stosic, S. Bennici, J.-L. Couturier, J.-L. Dubois, A. Auroux, Catal. Commun. 17 (2012) 23-28.

SSCI-VIDE+ATARI+ALI:SBE:AAU; National audience; Acrolein, the simplest unsaturated aldehyde, is widely used in chemical industry as intermediate for the synthesis of various widely used chemical products as biocides, acrylic acid, methionine and other numerous chemicals [1,2]. With the aim to find renewable materials easy to transform into acrolein, minimizing the investment on the existing plants, the oxidation of biosourced alcohols has been recently proposed. In this process, the oxidation of methanol and ethanol to formaldehyde and acetaldehyde and the aldol-condensation and dehydration of the two aldehydes to acrolein, are carried out simultaneously, contrarily to most of research works published up to now.The acid-base properties of the solid catalysts play a key-role in the aldol condensation reactions. Basic sites are essential to increase the activity and selectivity of aldolisation reactions, but their strength plays also an important role in side reactions. The quantification of the acid/base sites concentration and strength on the surface of oxide catalysts is even more crucial when the reaction is carried out in presence of oxygen, thus leading to over-oxidation reactions.In the present study, a series of oxide catalysts obtained by deposition of basic oxides (Na2O, K2O, MgO, CaO) on a silica support has been considered in the cross-condensation of aldehyde and formaldehyde to produce acrolein. The addition of different guest oxides of the first and second group of the periodic table, allowed to tune the acidity and basicity of the catalyst surface. The basic and acidic properties of the catalysts have been investigated by adsorption calorimetry (see Figure) in order to obtain the concentration, strength and strength distribution of the active sites. Finally, the catalytic reaction has been performed in presence of oxygen with the aim to verify how in oxidizing conditions the acid/base properties can impact the activity and selectivity towards acrolein.

SSCI-VIDE+ATARI+ALI:TWE:SBE:AAU; National audience; Acrolein, the simplest unsaturated aldehyde, is widely used in chemical industry as intermediate for the synthesis of various chemical products as biocides, acrylic acid, methionine and other numerous chemicals [1]. Production of acrolein starting from the oxidation of biosourced alcohols has been proposed recently [2].In the present work, production of acrolein from a mixture of alcohols (methanol and ethanol) is studied in a two-stage gas-phase process, in order to understand the reaction mechanism. Oxidation of methanol and ethanol on FeMoOx (Iron-Molybdate) catalyst takes place in the first stage reactor [2]; then the formaldehyde and the acetaldehyde produced feed the second stage reactor where acrolein is produced by aldol condensation (in the presence of O2 and other 1st stage reaction gases) on silica-supported CaO, MgO, Na2O and K2O catalysts [3]. We characterized acidity and basicity of the catalysts surface by adsorption calorimetry, using NH3 and SO2 respectively as probe molecules (Fig.1). The other physico-chemical properties were determined as well using complementary techniques like XRD, XPS, N2-adsorption at 77K.The catalytic reaction has been performed with the aim to verify how in oxidizing conditions the acid/base properties can impact the activity and selectivity towards acrolein. We tested the catalysts at different temperatures in order to maintain the CO+CO2 yield below 10 mol %. Good performances were obtained for Na/Si catalyst with 25% acrolein yield and 10% CO+CO2 yield. K/Si and Ca/Si catalysts showed the lowest acrolein production; they promoted side oxidation reactions that overoxidized acrolein (or reactants) into CO and CO2, due to the presence of oxygen. Mg/Si presented the best results (at 320 °C and 5000 h-1 GHSV) with 29% and 38% of acrolein yield and selectivity, respectively, and a CO+CO2 yield of 7% (Fig.2). The presence of both acid and basic sites seems to increase the selectivity towards acrolein. The fine tuning of the surface properties is necessary to improve the acrolein selectivity and to minimize the over oxidation behavior.

SSCI-VIDE+ATARI+ALI:SBE:AAU; International audience; We studied the production of acrolein from a mixture of alcohols in a two stages gas-phase process to understand and decouple the reaction mechanism. Oxidation of methanol and ethanol on FeMo catalyst takes place in the first stage reactor [1]; then the formaldehyde and the acetaldehyde produced feed the second stage reactor where acrolein is produced by aldol condensation (in the presence of O2 and other 1st stage reaction gases) on silica-supported CaO, MgO, Na2O and K2O catalysts [2]. We characterized the catalysts for their acid and base surface properties, by adsorption calorimetry, using NH3 and SO2 respectively as probe molecules (Fig.1). The other physico-chemical properties were also determined by complementary techniques as XRD, XPS, N2-adsorption at 77K.We tested the catalysts couples at temperatures chosen in order to maintain the CO+CO2 yield below 10 mol %. K-Si and Ca-Si catalysts showed the highest oxidation features and could not be tested above 270 and 300 °C, respectively, despite the acrolein selectivity that might improve at higher temperatures. In each case, the catalysts produced mainly acrolein, acetaldehyde, formaldehyde, CO and CO2.MgO-containing catalyst (Mg-Si) is the most promising and shows the highest acrolein selectivity and the highest amount of both acid and base strong sites (>100 kJ/mol) (Fig.2). Strong basic and acidic sites, as well as a good dispersion of the active oxides on the silica surface, drive the catalytic performances. The fine tuning of the surface properties is crucial to improve the acrolein selectivity and to minimize the over oxidation behavior.

SSCI-VIDE+ATARI+SBE:AAU; National audience; Thermally driven adsorption processes like heat pumps or cooling applications are important for saving primary energy. The use of porous adsorbents in the field of seasonal heat storage in building is an attractive solution for the reducing of energy consumption as well as improving thermal comfort [1]. In recent years, there have been significant research progresses on microporous adsorbent materials for closed/open systems [2]. Thermochemical heat storage (TCS) is based on the reversible chemical and physical sorption of gases, mostly water vapor, in solid. The water adsorption capacity and heat generated are the most important properties for adsorbents in such TCS system. This study focuses on the determination of sorption capacity and heats of adsorption/desorption of water vapor for different zeolites (MOR, CLP, K-L, 3A, 4A, 5A, Na-X, Na-Y, H-Y, Ca-X and Li-X) and zeolite-type materials like SAPO and AlPO. The measured heats of dehydration (kJ.kg-1) varied in the 360-950 kJ.kg-1 range for the different samples that present also different water vapor sorption capacities (from 0.09 kgH2O. kg-1 to 0.26 kgH2O.kg-1). This behavior can be attributed to the strong interaction of water molecules with the electronegativity of charge-balancing cations of the different zeolites and with the pore size.Relationships between water adsorption in zeolites, the porous structure, the Si/Al ratio, the zeolite framework and the compensating cation have been established. The knowledge of the structural modifications induced by temperature and of the stability of these materials is of prime importance to ensure their durability and effectiveness for seasonal heat storage applications.

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SSCI-VIDE+ATARI+AJA:SBE:AAU; National audience; IntroductionThermally driven adsorption processes like heat pumps or cooling applications are important for saving primary energy. The use of porous adsorbents in the field of seasonal heat storage in building is an attractive solution for the reducing of energy consumption as well as improving thermal comfort [1]. In recent years, there has been significant research progress on microporous adsorbent materials for closed/open systems [2]. Thermochemical heat storage (TCS) is based on the reversible chemical and physical sorption of gases, mostly water vapour, in solids. The water adsorption capacity and heat generated are the most important properties for adsorbents in thermochemical heat storage systems. 2Experimental/methodology In order to understand the adsorption-desorption behaviour of different kinds of commercial nanoporous molecular sieves (with different structures, Si/Al ratios and balancing cations), materials were characterised in their structural, textural and surface properties by using appropriate techniques (N2 isotherms and XRD) and by adsorption of water vapour using Setaram TG-DSC 111 apparatus. Successive cycles of hydration (at 20°C) / dehydration (at 150 °C) were performed to check the cyclability of the system. 2Results and discussion The experimental results obtained for zeolites (MOR, CLP, K-L, 3A, 4A, 5A, Na-X, Na-Y, H-Y, Ca-X and Li-X) and zeolite-type materials like SAPO and AlPO are reported. The measured heats of dehydration (kJ.kg-1sample) vary in the 360-950 kJ.kg-1sample range for the different samples those present also different water vapor sorption capacities (from 0.09 kgH2O.kg-1sample to 0.26 kgH2O.kg-1sample). As example the dehydration enthalpy values determined for zeolites type Linde A (3A, 4A and 5A) follow the order: 4A (about 800 kJ.kg-1sample) > 3A (about 660 kJ.kg-1sample) > 5A (about 614 kJ.kg-1sample). This behaviour can be attributed to the strong interactions of water molecules with the electronegativity [3] of charge-balancing cations of the different zeolites and with the pore size. 4Conclusions A relationship between water adsorption behavior on zeolites, the porous structure, the Si/Al ratio, the zeolite framework and the extraframework monovalent cation which showed the strongest affinity to water, has been established. The knowledge of the structural modifications induced by temperature and of the stability field of these materials is of prime importance to ensure their durability and effectiveness for seasonal heat storage applications. Based on the experimental investigations of the different materials, the kinetics of the adsorption and desorption processes was analyzed.Acknowledgements The authors acknowledge the French Ministry of High Education and Research for the PhD-student fellowship allocated to A. Jabbari-Hichri and the scientific services of IRCELYON for their valuable help in the characterization of the samples.References [1] P. Tatsidjodoung, N. Le Pierrès, L. Luo, Renew . Sust. Energ. Rev., 18 (2013) 327-349.[2] N. Yu, R.Z. Wang, L.W. Wang, Prog. Energ. Combust., 39 (2013) 489-514.[3] E.P. Ng, S. Mintova, Micropor. Mesopor. Mat., 114(2008)1-26.

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