Distinctive features of composts of different origin: a thorough examination of the characterization results

The potential of composts produced from different origin residues to be used in environmentally friendly agriculture is addressed in this work. Seven composts obtained from different raw materials and composting methodologies are compared using elemental, thermal and spectroscopic characterization data. Despite the stabilization of the organic matter in all composts being adequate for agricultural applications, they display distinct elemental and structural compositions. Likewise, the fertilisers have very different effects on lettuce growth. Despite the observed differences, some common features were found, namely a mass loss (TGA) of 25.2 g per mol C, association between groups of elements (Fe, Al, Ni, Co, Cr, Cu and S; Mg, Na, K and P, C, Coxi, N and Pb) and correlations between the amount of carbon nanostructures and the characteristic aromaticity parameters. These results suggest that the tuning of the compost features for specific cultures may be possible for sustainable food production.This work was financially supported by the Interreg VA Spain-Portugal Programme (EU) through the project Res2ValHum (0366_RES2VALHUM_1_P). A.C. Silva acknowledges receipt of a PhD grant (UMINHO/BD/40/2016) financed by the Operational Programme Norte 2020 (through the Project “NORTE-08-5369-FSE-000033”). A. Teixeira acknowledges the grant (Res2ValHum 01/2018) to develop experimental work for 11 months on the project. J. Antelo and S. Fiol are also grateful for the financial support provided by Xunta de Galicia—Consellería de Educación e Ordenación Universitaria de Galicia (Consolidation of Competitive Groups of Investigation; GI-1245, ED431C 2018/12 and CRETUS AGRUP2015/02, ref. 2018-PG10)

ISC 235 : Characterization of the Opalinus clay after experimentation IC. Technical note TN 2016-63

Note technique rédigée dans le cadre d'une collaboration avec l'ANDRA sur des échantillons issus d'une expérience effectuée dans le cadre du Mont Terri Projec

Ni isotopic fractionation at the interface with mineral phases

International audienceNickel isotopes have recently been proposed as a new tool to investigate the metal biogeochemical processes. However, a complete comprehension of reaction mechanisms responsible for Ni isotopic fractionation factors is still missing1,2. In this study, the isotopic tool was combined with X-Ray Absorption Spectroscopy to associate Ni isotopic fractionation to the modification of its chemical speciation. Nickel sorption isotherms were conducted on pure mineral phases with cation exchange capacity (nontronite) and without (goethite, talc, and calcite). X-ray absorption spectra at Ni K-edge were collected on solid phases in fluorescence mode. Nickel predominantly forms outer-sphere complexes at nontronite surface. The weakness of electrostatic bonds may explain the negligible isotopic fractionation Δ60Nisorbed-dissolved observed for this charged clay mineral. When mineral phases present specific surface sites, e.g. talc and goethite, a preferential sorption of light isotopes was observed, in agreement with previously published data1,2. Δ60Nisorbed-dissolved was between -0.29 and -0.86‰ for talc, and -0.43 and -0.94‰ for goethite (2σ=0.05‰). For goethite, the increase of [Ni] promotes the sorption of light isotopes as a consequence of competition for specific surface sites. For calcite, increasing the amount of Ni sorbed from 3 % to 82 %, Δ60Nisorbed-dissolved varied between -0.23‰ and +0.17‰, respectively. The spectroscopic data of Ni-CaCO3 showed the presence of a Ni second neighbor (at 3-3.3 Å) that can be attributed to surface precipitation.These preliminary results suggested that, as goethite, at low % of Ni sorbed, calcite is enriched in light isotopes, but formation of Ni(CO3)2 in solution and successive precipitation could contribute to the association of heavy isotopes with the solid phase

Long term behavior of iron and zinc in steelmaking wastes

International audienceBlast Furnace Sludges (BFS), by-products of iron pig making, are characterized by relatively high contents of trace metals (Zn, Pb, Co, Cr) and iron (20-30%) [1, 2]. During the last century, such wastes were released in the environment (soils and aquatic media), and underwent various weathering conditions (anoxic or oxic conditions). Since iron bearing phases are widely reported to readily scavenge trace metals, specific investigations were perfomed to unravel the evolution of both iron and zinc speciation in those various physico-chemical conditions. A set of BFS was collected on ancient sites and from an active iron pig plant, including freshly produced and weathered BFS samples. A multi-scale analysis was performed using the combination of microscopic and microspectroscopic techniques (XRD, TEM, microXRF, and bulk and micro-XAS at the Fe and Zn K-edges). In anoxic conditions, besides the predominance of zinc sulfides, TEM and XAS data evidenced supplementary Zn bearing phases, including Zn adsorbed onto iron oxyhydroxides and Zn inserted in neoformed iron rich phyllosilicates. The neoformed Fe-rich clay minerals appear to be related to the oxidation of metallic iron spheres and/or iron oxides (mainly wustite and magnetite). The latter Fe bearing minerals are ubiquitous in BFS as evidenced by XRD patterns and XAS spectra at the Fe K-edge. Furthermore, TEM investigations strongly suggest a link between the formation of Fe-rich clays and Zn sulfides. In oxic conditions, Zn was shown to be mainly included in double lamellar hydroxydes for high Zn contents (15-20%), or in the neoformed phyllosilicates for lower Zn contents (about 0.1%). [1] Kanbar et al. (2017) Sci. Total Environ. 599–600, 540–553. [2] Kretzschmar et al. (2012) Environ. Sci Technol. 46, 12381-1239

Molecular geochemistry of Zn in continental rivers

International audienceWidely used in industry and commonly encountered in numerous domestic products, Zn is ubiquitous in continental waterbodies, in sediments and suspended particles (SPM). This element is therefore often used as a marker of anthropogenic inputs in aquatic media. In this context, Zn behavior in rivers of the Moselle watershed (french part) was investigated, from low- to highly impacted areas such as ancient steel-making watersheds [1-2].Zn speciation was investigated through spectroscopic tools as a possible fingerprint of environmental processes and sources, in order to decipher lithogenic, urban or industrial particles. Combined to element and mineralogical compositions by ICP-MS, XRD and TEM-EDXS analyses, XAS spectra at Zn K-edge were acquired at low temperature in bulk and microscopic modes, on environmental and reference samples. In sediments, XANES and EXAFS spectroscopies confirmed the predominance of amorphous Zn sulfides and unraveled minor Zn oxide species. The linear combination fitting of XANES spectra obtained on SPM, combined to the Zn concentration determination, was particularly helpful to evidence specific Zn sources during river floods. During high flow regime, dioctahedral clay minerals were evidenced as the main Zn bearing suspended particles and fingerprint the speciation of naturally occuring Zn. Those investigations demonstrate the added value of Zn speciation to monitor and understand the water-sediment interface as well as the power of synchrotron-based tools to study environmental matrices.[1] Kanbar et al. (2017) Sci. Total Environ. 599–600, 540–553. [2] Montargés-Pelletier et al. (2014) Envir. Sci. Poll. Res., 21, 4, 2744-2760

Spatial and temporal variations of particulate organic matter from Moselle River and tributaries: A multimolecular investigation

International audienceThe spatial and temporal composition of organic matter (OM) was investigated in the Moselle watershed (Lorraine, France). The spatial composition was studied using different stations along the river and four tributaries. In addition, one anchor station was used in order to better understand the temporal OM composition during different hydrologic regimes and seasons. The first part of the organic characterization consisted of the extraction of the lipid. OM with an automatic extractor. The extracts were analyzed for their lipid fatty acids (Lip-FAs), polycyclic aromatic hydrocarbons (PAHs) and sterols using gas chromatography-mass spectrometry (GC–MS). The insoluble fraction was also analyzed with thermochemolysis-GC–MS (TMH-GC–MS) using tetramethylammonium hydroxide (TMAH) and lignin phenols, permethylated deoxy aldonic acids and refractory FAs (Ref-FAs) were analyzed. The results showed that one station (Florange station) on the small Fensch stream tributary displayed variation in the composition of the molecular OM, with higher microbial markers (C16:1, C18:1w7, C18:1w9, coprostanol) inputted to the highly industrialized and urbanized areas in this small sub-catchment. The other stations showed rather similar organic composition (Lip-FAs, Ref-FAs, sterols, lignin compounds, PAHs) due to the size of the catchment (10,000 km2) or the integrative state of the suspended particulate matter (SPM). The regime flow involved a decrease in SPM OM content as well as a decrease in the palmitoleic acid/palmitic acid (C16:1/C16:0) ratio and an increase in the (stigmastanol + sitostanol + stigmasterol + sitosterol)/(cholesterol + cholestenol) (C29/C27(ST)) ratio, revealing the presence of more allochthonous OM. The increase in regime flow was also correlated with a growing contribution of more degraded OM to the SPM that could be related to the leaching of subsurface soils from the watershed or to the remobilization of surface sediments. Seasonal variations were also observed, with a stronger contribution of autochthonous production during low flow level in summer. The work shows the importance of OM characterization of SPM in order to better assess the spatial and temporal OM variation in the water column

Impact of intracellular metallothionein on metal biouptake and partitioning dynamics at bacterial interfaces

International audienc

Characterization of suspended particulate matter in the Moselle River (Lorraine, France): evolution along the course of the river and in different hydrologic regimes

International audienc

Controlled assembly of heterogeneous aggregates of clay, iron hydr(oxydes) and polysaccharide: Effects of preparation conditions

International audienceThe preparation of well-defined organo-mineral assemblies under controlled conditions is required to improve our understanding of the formation and surface reactivity of micrometric aggregates, ubiquitous in soils and continental aquatic media. We aim at investigating the building of organo-mineral assemblies with a specific focus on the assembly mode and its consequence on the final properties of the micrometric aggregates. In this work, the preparation and detailed characterization of clay-size aggregates composed of a clay mineral (illite), organic polymer (Dextran polysaccharide) and iron (hydr)oxide are reported, with a focus on the structural organization of the generated aggregates. A step-by-step strategy was developed, and three sets of clay-size composites were prepared with illite particles as a starting material. In two first steps, two distinct sets of two-component composites were obtained according to different procedures. Illite‑iron (hydr)oxide composites were obtained by alkaline hydrolysis of iron in the presence of illite particles, and illite-Dextran aggregates were obtained through the addition of Dextran polysaccharide to an illite suspension. In a third step, three-component micro-aggregates were obtained by subsequent addition of Dextran to suspensions containing the formed illite‑iron (hydr)oxide composite. The so-prepared 2- and 3- component aggregates were investigated by electrophoresis, electron microscopy, X-ray absorption and FTIR spectroscopies. For materials containing Dextran, electrophoretic mobility measurements evidenced variations of surface charge, combined with an increase of aggregate size highlighted by dynamic light scattering. Electron microscopy and EXAFS at iron K-edge evidenced the precipitation of nanoparticles of iron (hydr)oxide onto clay mineral surfaces. FTIR data in transmission and diffuse reflectance modes supported not only the adsorption of Dextran but also the preferential localization of Dextran at the external surfaces of the aggregates. All in all, data collected on the two- and three-component materials demonstrated that the presence of iron (hydr)oxide nanoparticles on the surface of illite strongly modified the organization of organic and mineral constituents

Natural suspended particulate matter (SPM) versus lab-controlled particles: Comparison of the reactivity and association mode of Zn

International audienceRiver suspended particulate matter (SPM) plays a crucial role in the fate and behavior of pollutants such as Zn, a widespread trace metal commonly encountered in continental surface waters. SPM comprises particles and colloids and is described as complex, heterogeneous particles composed of mineral, organic and microbiological components with high surface reactivity. In this study, the surface properties of river SPM and its capacity to bind Zn were probed using electrophoretic mobility (EM) experiments, specific surface area (SSA) measurements, Zn adsorption tests and X-ray absorption spectroscopy (XAS). The external characteristics and reactivity of lab-controlled mineral phases (illite, ferrihydrite, illite-iron (hydr)oxide composite, and calcite) were investigated as for natural SPM. The electrophoretic mobility (EM) of the SPM exhibited low variations among the samples and was essentially assigned to the clay particles that dominate the mineralogical composition. Except for two samples, Zn adsorption experiments evidenced comparable adsorption capacity in relation to their different mineral and chemical compositions. Zn K-edge XAS data revealed that at low Zn loadings, the binding mode of this metal with environmental particles was controlled by its mineralogical composition. Indeed, linear combination fitting of the XAS curves, completed by shell-to-shell fitting, revealed that Zn is associated with SPM by surface complexation. The XAS results showed that for SPM samples collected in the high flow regime, Zn was mainly bound to clay minerals. In contrast, for the SPM sample collected during the low flow regime, Zn was bound not only to clay minerals but also to iron (hydr)oxide