Interest of phosphate amendments on metal-contaminated soils in order to elaborate to produce heterogeneous supported catalysts from plant biomass that can be used in organic synthesis

De nombreux sols contaminés par les éléments métalliques résultent des activités humaines et industrielles. Pour gérer ces sols, la technique du phytomanagement a séduit les scientifiques et les gestionnaires des sites pollués. Tout en utilisant le génie végétal, cette technique permet de produire des biomasses qu’il convient de valoriser. Sur la base de cette approche, le présent travail décrit cette technique en utilisant des biomasses (raygrass et miscanthus) en association à des amendements phospho-calciques. Ces biomasses, décrites comme étant non-hyper-accumulatrices des éléments métalliques, ont été produites sur des terres de jardins et des terres agricoles. Les expérimentations ont été menées en serre, en mésocosme, et in situ, à proximité de l’ancienne fonderie de plomb Metaleurop Nord.L’utilisation raisonnée des composés phospho-calciques n’a pas affecté significativement les caractéristiques physico-chimiques et biologiques des sols. En revanche, il a pu être montré une amélioration de certains paramètres physiologiques des plantes. Par ailleurs, les composés phospho-calciques ont généralement réduit l’extractabilité et la phytodisponibilité de Cd et Pb tout en favorisant la mobilité et le transfert d’éléments d’intérêt vers les parties aériennes des biomasses. Ceci a permis de transformer ces biomasses en écocatalyseurs. Après avoir été caractérisés, ces derniers ont été utilisés en synthèse organique et leur recyclabilité a été montrée. Trois exemples ont été présentés dans le cadre du présent travail. Dans une perspective d’utilisation d’autres biomasses, les concentrations en éléments métalliques dans des plantes rudérales ont été déterminées.Many metal-contaminated soils result from human and industrial activities. To manage these soils, the phytomanagement has attracted scientists and managers of contaminated sites. While using plant engineering, this technique produces biomass that should be valued. Based on this approach, the present work describes this technic by using plant biomass (ryegrass and miscanthus) in combination with phosphocalcic amendments. These biomass, described as non-hyper-accumulators, were produced on garden soils and agricultural soils. The experiments were conducted in greenhouse, mesocosm and in situ near the former Metaleurop Nord smelter. The sustainable use of phosphocalcic compounds did not significantly affect the physicochemical and biological characteristics of soils. In contrast, some physiological parameters of plants were improved. In addition, the phosphocalcic compounds decreased the extractability and phytavailability of Cd and Pb in some cases while promoting the mobility and the transfer of other metallic elements from the soil to the aerial parts of the biomass studied. Metal-enriched biomass were transformed into ecocatalysts. After being characterized, these ecocatalysts were used in organic synthesis and their recyclability was demonstrated. Three examples have been detailed in the current thesis report. In view of using other biomass, metal concentrations in ruderal plants were determined

Benefits of Ryegrass on Multicontaminated Soils Part 1: Effects of Fertilizers on Bioavailability and Accumulation of Metals

ACLEffects of three phosphorus fertilizers on the shoot biomass and on the accumulation of alkali, alkaline earth, and transition metals in the shoots and roots of ryegrass were studied with two contaminated garden soils. Phosphates were added in sustainable quantities in order to reduce the environmental availability of carcinogenic metals (e.g., Cd and Pb) and to enhance the bioavailability of alkali and alkaline earth metals as well as micronutrients needed by plants. Addition of Ca(H2PO4)2 was the most convenient way to (i) limit the concentration of Cd and Pb, (ii) keep constant the transfer of macro- and micronutrient from the soil to the ryegrass shoots, (iii) decrease the availability of metals, and (iv) increase the ratio values between potential Lewis acids and Cd or Pb in order to produce biosourced catalysis. For instance, the real phytoavailability was reduced by 27%–57% and 64.2%–94.8% for Cd and Pb, respectively. Interestingly, the real phytoavailability of Zn was the highest in the least contaminated soils. Even if soils were highly contaminated, no visual toxicity symptoms were recorded in the growing ryegrasses. This indicates that ryegrass is suitable for the revegetation of contaminated gardens. To promote the sustainable ryegrass production on contaminated soils for production of new organic fragrance and drugs in green processes according to REACH (Registration, Evaluation, Authorisation, and Restriction of Chemicals) regulation, two processes should be recommended: assisted phytostabilization of the elements, and then assisted phytoextraction by using chelators. View Full-Tex

From the contaminated soils to the ecocatalysts: An original investigation

COMInternational audienceThe number of contaminated sites by metals and metalloids (As, Cd, Cu, Pb and Zn) was around 1 250,000 in Europe in 2016. Most of them are located in France, notably in Northern France where numerous habitants live due to the high past industrial activities (mining, metallurgical, inorganic and organic chemistry). Consequently, environmental and sanitary problems like degradation and perturbation of soil activities (loss of the biodiversity…), non-compliant agricultural commodity, production of contaminated vegetables, lead poisoning and different types of symptoms in relation with metal human exposure were highlighted. This explains why the management of these contaminated soils (agricultural, urban and forest) is a great concern in the Hauts-de-France region and particularly in the contaminated area affected by the dust emission of two former lead and zinc smelters.Physical and chemical techniques (soil removal, soil washing, electrokinetic…) are widely used to remediate contaminated soils. However, most of them are expensive and destructive (fauna and flora are highly impacted and the resulting soils are often non-productive).To avoid the dispersion of contaminated soil particles, to restore contaminated sites and ecosystems and to maintain an economic activity in this area, an environmental friendly management based on the concept of assisted-phytoremediation and assisted-phytoextraction was studied. From this approach, the first interest was to immobilise the carcinogenic metals (Cd, Pb) and the second was to increase non-carcinogenic metal uptake by plants in order to elaborate new heterogeneous catalysts (called ecocatalysts) from the plant biomass. These bio-sourced catalysts were used in organic synthesis to produce pharmaceuticals taking into account the green chemistry concept. It was highlighted that these new catalysts were reusable, increased the reaction yields while minimizing the production of waste

Ecocatalysis for the synthesis of high-added molecules for therapeutic purposes. Innovative techniques for chemistry and processes

INVInternational audienc

An original approach in green chemistry: From assisted-phytoremediation of contaminated soil to upcycling of plant biomass for biosourced catalyst production

ACTIInternational audienceA kitchen garden soil was sampled in a contaminated urban area located in the north of France. Samples were air-dried and crushed to pass through a 10-mm stainless steel sieve. Due to the high heterogeneity of garden soils in the studied area, much attention have been paid on the homogeneity of soil samples. After this step, the mass of sampled soils (48 kg) was divided to obtain four subsamples Each of them was divided in six replicates, unamended or amended using dicalcium phosphate (DCP) or monocalcium phosphate (MCP) or a mixture of these two compounds (MxP=75%DCP+25%MCP) The phosphorous amendments were added into the soil in small quantity (0.02 %) with the aim at reducing the environmental availability of carcinogenic metals and to increase the Zn availability (Figure 1) After the stabilisation period (2 months) in a greenhouse, 1 5 g of ryegrass seeds (Lolium perenne L.) were sown in the 24 containers. Eight weeks after sowing, ryegrass shoots were harvested, oven-dried at 40 °C and calcined at 500 °C in a muffle furnace (Nabertherm P330, Lilienthal, Germany)

Phytomanagement of contaminated soils by potentially toxic metals in urban areas: A new approach combining sustainable amount of phosphates and ryegrass

ACTNInternational audienc

A sustainable approach to manage metal-contaminated soils a preliminary greenhouse study for the possible production of metal-enriched ryegrass biomass for biosourced catalysts

International audienceTwo kitchen garden soils (A and B) sampled in contaminated areas were amended using phosphates in sustainable quantities in order to reduce the environmental availability of potentially toxic inorganic elements (PTEs) and to favour the availability of alkali, alkali earth and micronutrients. The environmental availability of PTEs was evaluated using a potential plant for revegetation of contaminated soils (ryegrass) and a mixture of low molecular weight organic acids. Despite the highest contamination level of B, the concentration of metals was highest in the ryegrass shoots grown on A for the two harvests. These results correlated well with those obtained using low molecular weight organic acids for Cd, Zn and Cu, whereas this mixture failed to represent the transfer of nutrients due to the presence of biological and physiological mechanisms. The statistical differences between the biomass of ryegrass obtained at the first and the second harvests were attributed to the decrease of available potassium, implicated in the growth and development of plants. Phosphates increased the ratios Zn/Cd, Zn/Pb and Zn/Cu up to 176 ± 48, 38 ± 6 and 80 ± 12, respectively, and made possible the reduction of the concentration of Cd and Pb in the shoots of ryegrass by 22% and 25%, respectively. The concentration of Zn in the shoots of ryegrass from the first and the second harvests grown on soil A were in the range 1050–2000 mg kg−1, making this plant a potential biomass to (i) produce biosourced catalysts for organic chemistry applications in a circular economy concept and (ii) limit human exposure to commercial Lewis acids. A preliminary application was identified. © 2019, Springer Nature Switzerland AG

Can we rely on the soil seed bank for restoring xeric sandy calcareous grasslands?

ACLIn western Europe, xeric sandy calcareous grasslands have been reduced to a few small and isolated fragments, as a result of sand quarrying and abandonment of agro-pastoral practices leading to tree encroachment. The restoration of dry grasslands usually consists of reopening the land by cutting trees and removing the litter or the topsoil, relying on seed rain and soil seed bank for recolonization. We investigated whether the soil seed bank of degraded sandy grasslands can be a suitable tool in the restoration of typical sandy grassland communities. We examined the soil seed bank and the vegetation composition in a total of 20 plots of extant and recently restored sandy grasslands (Sedo-Cerastion) in southern Belgium. Seed density ranged from 611 to 38,808 seeds/m2. Dry grassland species accounted for 42% of the soil seed bank in extant grasslands but dropped to 17% for restored sites, which were dominated by species from artificial pioneer habitats. Only a small number of the 122 species recorded in the vegetation germinated from the soil seed bank samples. Most of these were common species with large ecological amplitude (e.g., Arenaria serpyllifolia, Poa annua, and Rumex acetosella), already present in the site. The typical sandy grassland specialists (e.g., Cardaminopsis arenosa, Dianthus deltoides, Helichrysum arenarium, and Petrorhagia prolifera) were missing from the seed bank, except when present in the vegetation. Therefore, a successful restoration of degraded sandy grasslands based on local seed banks is unlikely. Additional management actions, such as active seed sowing of target species, may be necessary

Valorization of new eco-catalysts in the synthesis of new antitumor compounds

International audienc

An innovative and efficient method to synthesize meloxicam in one-step procedure with respect to the green chemistry

International audienceAn improved procedure for the synthesis of meloxicam drug (methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazol-2-amine-3-carboxylate 1,1-dioxide) was described in one-step using mainly impregnated montmorillonite K10 (MK10) with ZnCl 2 as a heterogeneous catalyst. This innovative method was compared to the last described procedure employed in the manufacture of this anti-inflammatory drug by means of some metrics used in a first step of the evaluation process of the environmental impact of a chemical transformation. Apart from the yield, which was 90%, atom economy, waste, environmental factor, reaction mass efficiency and stoichiometric factor were calculated as 91.6%, 8.4%, 0, 8.1% and 1%, respectively. Interpretation of these metrics was given and highlighted the fact that the strategy used in the current study may be considered as an environmental-friendly and sustainable method that fits well in the green chemistry concepts. © 2018, Iranian Chemical Society