Etude electrochimique de l'hemine et de cytochromes de type c a l'electrode de graphite pyrolytique. Interaction entre le cytochrome c3 et l'hydrogenase de Desulfovibrio desulfuricans Norway

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 79343 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Hybrid clay-based materials for the treatment of pesticide-contaminated water

The International Conference on Advanced Materials, Nanosciences and Applications (ICAMANA 2019), Oujda (Morocco), 10th-13th december 201

Physico-chemical characterization of clays from Assa-Zag for valorization in cationic dye methylene blue adsorption

International audienc

Synthesis and multifaceted use of phosphorylated graphene oxide: growth of titanium dioxide clusters, interplay with gold nanoparticles and exfoliated sheets in bioplastics

International audienceFive different functional phosphorus motifs were trivially installed within graphene oxide (GO) sheets to provide water-dispersible and thermally-stable phosphorus graphene oxide materials (PGO). The presence of exogenous phosphorus heteroatoms on the surface of the tiny carbon sheets was harnessed for the anchoring and growth of metal oxide clusters, exemplified herein by titanium dioxide, and for the chelation and stabilization of small gold nanoparticles. Unexpectedly, both GO and PGO promoted crystallization in a low-temperature liquid-phase medium without thermal annealing treatment. However, the fingerprint of the surface chemistry is illustrated through the formation of different species; while discrete anatase nanoparticles were selectively formed on the surface of GO sheets, a biphasic mixture of anatase and rutile was grown on PGO. The latter provides a more stable material owing to the robustness of the interfacial P–O–Ti bridges. Strong coordination to gold nanoparticles was also observed for PGO due to the presence of P[double bond, length as m-dash]O(OH)2 fragments, compared to the weakly coordinating oxygenated functions in GO. Lastly, the possible delamination of PGO sheets associated with their improved thermal stability renders them promising nanosized fillers for carbohydrate-based bioplastics

Polysaccharide templated biomimetic growth of hierarchically porous metal-organic frameworks

International audienc

Organic sorbents as barriers to decrease the mobility of herbicides in soils.

49 páginas, 5 tablas, 3 figuras, 2 figuras suplementarias. -- The definitive version is available at http://www.elsevier.comNumerous organic sorbents have been introduced in recent years to develop technologies aimed at preventing the pollution of soil and water by pesticides. This work set out to study and compare the effect on the mobility of ethofumesate and terbutryn in a soil of five low-cost organic residues (grape marc, pine wastes, urban solid wastes, sewage sludge, and spent mushroom substrate), and two organoclays (swelling and non-swelling clays modified with octadecyltrimethylammonium). Herbicide leaching experiments were conducted under water saturated flow in hand-packed soil columns in which sorbents were incorporated as barriers. The breakthrough curves obtained were fitted to the one-dimensional transport model CXTFIT. The leaching of ethofumesate and terbutryn in the soil recorded figures of 96.0% and 66.9%, respectively, and when a barrier of organic residues or organoclays was incorporated into the column these amounts decreased for ethofumesate to 65.7–84.6% and 3.35–5.99%, and for terbutryn to 0.28–13.8% and 1.11–0.79%. The effect of the organoclay barriers was more significant for ethofumesate, while the effect of organoclays for terbutryn was close to that of certain organic residues. The barrier's impact was also observed in the variation of the retardation coefficients (Rexp), which increased by 3–202 or 3–40 times those coefficients for soil without a barrier. Distribution coefficients (K) increased 72–147 and 3771–9461 times (ethofumesate), and 46–986 and 264–747 times (terbutryn) for amended soils with both organic residues and organoclays, respectively. Significant inverse correlations were found for ethofumesate between sorption coefficients and leached amounts due to the relevant effect of the OC content of organic sorbents in these processes, although this was not the case for terbutryn whose behavior was linked to the OC nature of organic sorbents. The herbicide leaching data were well described by CXTFIT (mean square error, MSE < 1.2 · 10− 6) for most of the treatments, although it fell short with high sorption capacity barriers. Information from this study may be used to select an efficient method based on the use of sorbent barriers designed to prevent water contamination by pesticides.This work was funded by the “Agencia Española de Cooperación Internacional para el Desarrollo (AECID)” as a part of the Project 60/04/P/E and by MINECO/FEDER UE (Project AGL2015-69485-R).Peer reviewe

Bio-sourced porous cellulose microfibrils from coffee pulp for wastewater treatment

The present work describes the production of novel highly hydrated cellulose microfibrils (CMFs) with unique morphology from coffee pulp waste using specific chemical treatments. The as-produced CMFs were successfully characterized and then used as an adsorbent for removal of methylene blue (MB) from concentrated aqueous solutions. Surprisingly, it was found that the novel CMFs display high water-uptake ability, with a maximum swelling ratio of 265%, and that they form an entangled hydrated network gel in water. The morphological observation and nitrogen adsorption measurement demonstrated that the extracted CMFs exhibit an average fibril diameter of 11.5 µm and mesoporous structure with an average pore size of 6.37 nm. These special features make the as-produced CMFs excellent candidates to be used as adsorbents for removal of MB from concentrated solutions. The performed adsorption studies determined that the adsorption equilibrium was reached within 90 min. The adsorption kinetics data were well fitted to the pseudo-second-order kinetic model, and the adsorption isotherms were well described by the Freundlich isotherm model. In addition, the maximum adsorption capacity was 182.5 mg/g, much higher than that determined for other previously reported cellulose-based adsorbents. Through this study, we have demonstrated a possible strategy to give an added value to the coffee pulp waste, a by-product of the coffee processing industry, which is rich in cellulose, inexpensive and renewable source. Indeed, the extracted CMFs are very attractive for developing a sustainable and economically viable bio-sourced material for future growth of cellulose use in advanced applications

Synthesis and characterization of mesoporous geopolymer based on Moroccan kaolinite rich clay

International audienc

Synthesis and antibacterial behavior of bio-composite materials-based on poly(ε-caprolactone)/bentonite

Several clay minerals as inorganic fillers were incorporated to aliphatic polyester by various procedures. The target of enhancing the physicochemical properties of the resulting composite material leading thereby to overcome the limitations of neat polyesters. Still, bentonite (Bnt) as a clay mineral has been relatively unexplored as a reinforcing agent of the poly(ε-caprolactone) (PCL). In this study, a bio-nanocomposite based on poly (ε-caprolactone) & bentonite nanofiller was prepared by in-situ ring opening polymerization (ROP) of ε-caprolactone (ε-CL) under open air using tin-based catalyst. The obtained bio-composites (PCL-OBnt) were fully characterized to examine their structural interactions, thermal stability, mechanical, and morphological properties. Finally, the antimicrobial activity against S. epidermidis and S. aureus of the prepared bio-composites materials was evaluated