Experimental and Computational Evaluation of Heavy Metal Cation Adsorption for Molecular Design of Hydrothermal Char

A model hydrochar was synthesized from glucose at 180 °C and its Cu(II) sorption capacity was studied experimentally and computationally as an example of molecular-level adsorbent design. The sorption capacity of the glucose hydrochar was less than detection limits (3 mg g−1) and increased significantly with simple alkali treatments with hydroxide and carbonate salts of K and Na. Sorption capacity depended on the salt used for alkali treatment, with hydroxides leading to greater improvement than carbonates and K+ more than Na+. Subsequent zeta potential and infrared spectroscopy analysis implicated the importance of electrostatic interactions in Cu(II) sorption to the hydrochar surface. Computational modeling using Density Functional Theory (DFT) rationalized the binding as electrostatic interactions with carboxylate groups; similarly, DFT calculations were consistent with the finding that K+ was more effective than Na+ at activating the hydrochar. Based on this finding, custom-synthesized hydrochars were synthesized from glucose-acrylic acid and glucose-vinyl sulfonic acid precursors, with subsequent improvements in Cu(II) adsorption capacity. The performance of these hydrochars was compared with ion exchange resins, with the finding that Cu(II)-binding site stoichiometry is superior in the hydrochars compared with the resins, offering potential for future improvements in hydrochar design

Topology and design investigation on thin film silicon BIMOS device for ESD protection in FD-SOI technology

International audienc

Green composites based on thermoplastic starches and various natural plant fibers: Impacting parameters of the mechanical properties using machine-learning

peer reviewedMultivariate analyses on formulation and mechanical behavior of nonwoven and nonoriented natural fibers reinforced thermoplastic starch (TPS) composites were performed. Glycerol and water were considered as TPS plasticizers. Fibers composition (i.e., cellulose, hemicellulose, lignin), fibers morphology (fibers length), starch composition (i.e., amylose/amylopectin ratio) as well as the processing conditions (i.e., temperature, rotor speed, relative humidity during aging) were evaluated for their ability to affect the elastic modulus, tensile strength, and elongation at break of the final materials. Multivariate linear regressions were computed to unveil the importance of each variable on the mechanical behavior. Fibers composition impacted the most the models: cellulose maximization improved the elastic modulus and tensile strength while lignin reduced the elastic modulus and hemicellulose decreased the tensile strength. TPS plasticizers, temperature, and rotor speed of the process were negatively impacting the elastic modulus but in a lesser extent than the fiber composition. Within the range of the created database, the selected variables and attributed coefficients were permitted to explain the variability. The produced models revealed that complex and yet uninvestigated interactions are to be considered within TPS-based biocomposites. Therefore, this work discusses and suggests a “must-have” list of variables for comparable analyses of new TPS-based biocomposites using natural fibers as reinforcement

Topology and design investigation on thin film silicon BIMOS device for ESD protection in FD-SOI technology

International audienc

Climate, soil resources and microbial activity shape the distributions of mountain plants based on their functional traits

International audienceWhile soil ecosystems undergo important modifications due to global change, the effect of soil properties on plant distributions is still poorly understood. Plant growth is not only controlled by soil physico-chemistry but also by microbial activities through the decomposition of organic matter and the recycling of nutrients essential for plants. A growing body of evidence also suggests that plant functional traits modulate spe-cies' response to environmental gradients. However, no study has yet contrasted the importance of soil physico-chemistry, microbial activities and climate on plant species distributions, while accounting for how plant functional traits can influence species-specific responses. Using hierarchical effects in a multi-species distribution model, we investigate how four functional traits related to resource acquisition (plant height, leaf carbon to nitrogen ratio, leaf dry matter content and specific leaf area) modulate the response of 44 plant species to climatic variables, soil physico-chemical properties and microbial decomposition activity (i.e. exoenzymatic activities) in the French Alps. Our hierarchical trait-based model allowed to predict well 41 species according to the TSS statistic. In addition to climate, the combination of soil C/N, as a measure of organic matter quality, and exoenzymatic activity, as a measure of microbial decomposition activity, strongly improved predictions of plant distributions. Plant traits played an important role. In particular, species with conservative traits performed better under limiting nutrient conditions but were outcompeted by exploitative plants in more favorable environments. We demonstrate tight associations between microbial decomposition activity, plant functional traits associated to different resource acquisition strategies and plant distributions. This highlights the importance of plant-soil linkages for mountain plant distributions. These results are crucial for biodiversity modelling in a world where both climatic and soil systems are undergoing profound and rapid transformations