scholarly journals Toward a New Way for the Valorization of Miscanthus Biomass Produced on Metal-Contaminated Soils Part 2: Miscanthus-Based Biosourced Catalyst: Design, Preparation, and Catalytic Efficiency in the Synthesis of Moclobemide

2020 ◽  
Vol 13 (1) ◽  
pp. 34
Author(s):  
Théo Guérin ◽  
Alina Ghinet ◽  
Christophe Waterlot
Keyword(s):  
Contaminated Soils ◽  
Lewis Acids ◽  
Catalytic Efficiency ◽  
Catalyst Design ◽  
Synthetic Methods ◽  
Main Ingredient ◽  
Aerial Parts ◽  
Metallic Salts ◽  
Crude Mixture ◽  
Heterogeneous Biocatalyst

The conception of two biosourced catalysts (biocatalysts) using stems of miscanthus from the first part of this study are described herein. The temperature and the process used to extract metals from plant as mixture of Lewis acids were investigated in detail and proved to be essential in the design of the biosourced catalysts and their catalytic efficiency. One part of the crude mixture of Lewis acids extracted from the aerial parts of miscanthus plants was used without further treatment as a homogeneous biocatalyst (M1), and the other part was supported on montmorillonite K10 to provide a heterogeneous biocatalyst (MM1). M1 and MM1 were next tested in the synthesis of moclobemide (main ingredient of a drug used to treat depression) and led to excellent yield. Additional comparative experiments with different commercial metallic salts (NaCl, KCl, CaCl2, MgCl2, CuCl2, ZnCl2, FeCl2, FeCl3, MnCl2, and AlCl3) and their mixtures were carried out and underlined the importance of the multimetallic synergy on catalytic activity. Finally, a comparison of this new synthetic method assisted by the biosourced catalyst with the previously described procedures to access moclobemide was realized by calculating their green chemistry metrics. This study revealed that the use of the biosourced catalyst led to one of the greenest synthetic methods described today to produce moclobemide.

scholarly journals Phytoremediation Potential of Native Herbaceous Plant Species Growing on a Paradigmatic Brownfield Site

2021 ◽  
Vol 232 (7) ◽  
Author(s):  
N. Matanzas ◽  
E. Afif ◽  
T. E. Díaz ◽  
J. R. Gallego
Keyword(s):  
Plant Species ◽  
Contaminated Soils ◽  
Native Species ◽  
Low Cost ◽  
Plantago Lanceolata ◽  
Herbaceous Plant ◽  
Plant Interactions ◽  
Aerial Parts ◽  
Medicago Lupulina ◽  
Icp Ms

AbstractPhytomanagement techniques using native species allow the recovery of contaminated soils at low cost and circumvent the ecological risks associated with the use of non-native species. In this context, a paradigmatic brownfield megasite highly contaminated by As and Pb was sampled in order to analyze soil–plant interactions and identify plant species with phytoremediation potential. A survey was first carried out in a 20-ha area to obtain an inventory of species growing spontaneously throughout the site. We then performed another survey in the most polluted sub-area (1 ha) within the site. Pseudototal concentrations of contaminants in the soil, aerial parts of the plants, and roots were measured by ICP-MS. A detailed habitat classification was done, and a specific index of coverage was applied by means of a 1-year quadrat study in various sampling stations. Results converged in the selection of six herbaceous species (Dysphania botrys, Lotus corniculatus, Lotus hispidus, Plantago lanceolata, Trifolium repens, Medicago lupulina). All of these plants are fast-growing, thereby making them suitable for use in phytostabilization strategies. Furthermore, they are all easy to grow and propagate and are generally self-sustaining. All six plants showed accumulation factors below 1, thus revealing them as pseudomethallophytes and excluders. However, L. hispidus and M. lupulina showed translocation capacity and are considered worthy of further study.

Selective synthetic methods using vanadium-mediated redox reactions

2005 ◽  
Vol 77 (9) ◽  
pp. 1539-1557 ◽  
Author(s):  
Toshikazu Hirao
Keyword(s):  
Lewis Acids ◽  
Redox Reactions ◽  
Radical Reaction ◽  
Redox System ◽  
Synthetic Methods ◽  
Pinacol Coupling ◽  
Oxidative Transformations ◽  
Low Valent

Oxovanadium(V) compounds serve as Lewis acids with oxidation capability and induce one-electron oxidative transformations of organosilicons, organotins, organoaluminums, organoborons, organozincs, and/or their ate complexes. Low-valent vanadium-catalyzed stereoselective reductive transformations, including dehalogenation, pinacol coupling, and the related radical reaction, have been developed by constructing a multicomponent redox system in combination with a coreductant and an additive.

scholarly journals Nodulated White Lupin Plants Growing in Contaminated Soils Accumulate Unusually High Mercury Concentrations in Their Nodules, Roots and Especially Cluster Roots

Horticulturae ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 302
Author(s):  
Miguel A. Quiñones ◽  
Susana Fajardo ◽  
Mercedes Fernández-Pascual ◽  
M. Mercedes Lucas ◽  
José J. Pueyo
Keyword(s):  
Contaminated Soils ◽  
Lupinus Albus ◽  
White Lupin ◽  
Cluster Roots ◽  
Cluster Root ◽  
Bioaccumulation Factors ◽  
Aerial Parts ◽  
High Mercury ◽  
Lupinus Albus L ◽  
Hg Accumulation

Two white lupin (Lupinus albus L.) cultivars were tested for their capacity to accumulate mercury when grown in Hg-contaminated soils. Plants inoculated with a Bradyrhizobium canariense Hg-tolerant strain or non-inoculated were grown in two highly Hg-contaminated soils. All plants were nodulated and presented a large number of cluster roots. They accumulated up to 600 μg Hg g−1 DW in nodules, 1400 μg Hg g−1 DW in roots and 2550 μg Hg g−1 DW in cluster roots. Soil, and not cultivar or inoculation, was accountable for statistically significant differences. No Hg translocation to leaves or seeds took place. Inoculated L. albus cv. G1 plants were grown hydroponically under cluster root-promoting conditions in the presence of Hg. They accumulated about 500 μg Hg g−1 DW in nodules and roots and up to 1300 μg Hg g−1 DW in cluster roots. No translocation to the aerial parts occurred. Bioaccumulation factors were also extremely high, especially in soils and particularly in cluster roots. To our knowledge, Hg accumulation in cluster roots has not been reported to date. Our results suggest that inoculated white lupin might represent a powerful phytoremediation tool through rhizosequestration of Hg in contaminated soils. Potential uptake and immobilization mechanisms are discussed.

scholarly journals Molecular Rh(III) and Ir(III) Catalysts Immobilized on Bipyridine-Based Covalent Triazine Frameworks for the Hydrogenation of CO2 to Formate

Catalysts ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 295 ◽  
Author(s):  
Gunniya Gunasekar ◽  
Kwangho Park ◽  
Hyeonseok Jeong ◽  
Kwang-Deog Jung ◽  
Kiyoung Park ◽  
...  
Keyword(s):  
Density Functional ◽  
Three Dimensional ◽  
Catalytic Efficiency ◽  
Density Functional Theory Calculations ◽  
Catalyst Design ◽  
Two Dimensional ◽  
Functional Theory ◽  
Hydrogenation Of Co2 ◽  
Catalytic Reactivity ◽  
Reduced Activity

The catalytic reactivity of molecular Rh(III)/Ir(III) catalysts immobilized on two- and three-dimensional Bipyridine-based Covalent Triazine Frameworks (bpy-CTF) for the hydrogenation of CO2 to formate has been described. The heterogenized Ir complex demonstrated superior catalytic efficiency over its Rh counterpart. The Ir catalyst immobilized on two-dimensional bpy-CTF showed an improved turnover frequency and turnover number compared to its three-dimensional counterpart. The two-dimensional Ir catalyst produced a maximum formate concentration of 1.8 M and maintained its catalytic efficiency over five consecutive runs with an average of 92% in each cycle. The reduced activity after recycling was studied by density functional theory calculations, and a plausible leaching pathway along with a rational catalyst design guidance have been proposed.

scholarly journals Toward a New Way for the Valorization of Miscanthus Biomass Produced on Metal-Contaminated Soils Part 1: Mesocosm and Field Experiments

2020 ◽  
Vol 12 (22) ◽  
pp. 9370
Author(s):  
Marie Hechelski ◽  
Brice Louvel ◽  
Pierrick Dufrénoy ◽  
Alina Ghinet ◽  
Christophe Waterlot
Keyword(s):  
Organic Chemistry ◽  
Contaminated Soils ◽  
Lewis Acids ◽  
Toxic Elements ◽  
Field Experiments ◽  
Calcium Phosphates ◽  
Renewable Resource ◽  
Potentially Toxic Elements ◽  
Miscanthus Giganteus ◽  
P Fertilizers

The effects of P-fertilizers (mono- and di-calcium phosphates) on the bioavailability of metals and nutrients in leaves and stems of Miscanthus × giganteus were studied in mesocosm and field experiments in order to propose a new way for the valorization of miscanthus biomass. The concentration of potentially toxic elements was generally higher in stems than in leaves. Although P-fertilizers were added to contaminated soils under sustainable conditions (from 0.022% to 0.026% w/w), the average of leaf and stem biomass generally increased in the presence of P-fertilizers due to the changes in the speciation of phosphorus. Leaves of the investigated miscanthus may be of great interest as a catalyst in organic chemistry, since the Ca concentration was up to 9000 mg kg−1 DW. Stems represent a potential biomass that can be used as renewable resource of Lewis acids, currently used in organic syntheses (the sum of Zn, Cu, Mn, Fe, Mg, Si and Al was near 1000 mg kg−1 DW). The percentage of Cd and Pb in leaves and stems of miscanthus did not significantly change with P-fertilizers. Depending on the mesocosm and field experiments, it ranged from 0.004% to 0.016% and from 0.009% and 0.034% for Cd in leaves and stems, respectively, and from 0.004% to 0.015% and from 0.009% and 0.033% for Pb in leaves and stems, respectively.

scholarly journals Theoretical Study on CO2 Hydrogenation Mediated by Ru-PNP Pincer Complexes: An Implication Towards Rational Catalyst Design

2021 ◽  
Author(s):  
Shahnaz Rohman ◽  
Chayanika Kashyap ◽  
Amlan Kalita ◽  
Sabnam Ullah ◽  
Indrani Baruah ◽  
...  
Keyword(s):  
Density Functional ◽  
Activation Barrier ◽  
Co2 Reduction ◽  
Catalytic Efficiency ◽  
Catalytic Performance ◽  
Catalyst Design ◽  
Pincer Complexes ◽  
Functional Theory ◽  
Strain Model ◽  
Rational Catalyst Design

Catalytic CO2 reduction mediated by Ru-PNP pincer complexes has been studied using density functional theory (DFT). Calculations clearly reveal that modification of the PNP pincer framework by introducing planar conjugation in the backbone improves the catalytic efficiency. Activation strain model reveals that reduction of strain in the transition states with modified PNP framework associated with the insertion of CO2 molecule is responsible for lowering the activation barrier. Calculations also reveal that electron withdrawing substituents at the PNP ligand improves the catalytic performance.

Tuning the Edge-Site Activity of 2H Phase MoSe2 for Hydrogen Evolution Reaction via Sulfur Substitution and Strain Engineering

2020 ◽  
Vol 12 (10) ◽  
pp. 1446-1456
Author(s):  
Ziwei Xu ◽  
Guanghui Zhao ◽  
Mingyuan Wang ◽  
Jingjing Liang ◽  
Shahid Hussain ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Density Functional ◽  
High Efficiency ◽  
Low Cost ◽  
Catalytic Efficiency ◽  
Strain Engineering ◽  
Catalyst Design ◽  
Potential Candidate

The 2H phase MoSe2 of high chemical stability and excellent catalytic activity is a promising catalyst for the hydrogen evolution reaction (HER) as a potential candidate, due to its low cost, high efficiency and abundant production. However, the HER catalytic efficiency of MoSe2 largely depends on the activity of reaction sites including the basal plane and the edges, and remains low because only the Mo edge sites are active. Herein, we have calculated the structural stability, catalytic activity, and strain engineering on sulfur substituted MoSe2 catalytic structures (Mo(Se1–xSx)2) by density functional theory. The results demonstrate that most of Mo(Se1–xSx)2 monolayers are thermodynamically stable and the HER activity of the Mo(Se1–xSx)2 monolayers can be effectively tuned by both element substitution and strain engineering with the mechanisms uncovered at the atomic level. This study provides the experiments theoretical references for the novel catalyst design of the hydrogen evolution reaction.

scholarly journals Application of Halogen Bonding to Organocatalysis: A Theoretical Perspective

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1045 ◽  
Author(s):  
Hui Yang ◽  
Ming Wah Wong
Keyword(s):  
Crystal Engineering ◽  
Lewis Acids ◽  
Halogen Bond ◽  
Theoretical Perspective ◽  
Halogen Bonding ◽  
Catalyst Design ◽  
Methodology Development ◽  
Wide Range ◽  
Promising Area ◽  
Organocatalytic Reactions

The strong, specific, and directional halogen bond (XB) is an ideal supramolecular synthon in crystal engineering, as well as rational catalyst and drug design. These attributes attracted strong growing interest in halogen bonding in the past decade and led to a wide range of applications in materials, biological, and catalysis applications. Recently, various research groups exploited the XB mode of activation in designing halogen-based Lewis acids in effecting organic transformation, and there is continual growth in this promising area. In addition to the rapid advancements in methodology development, computational investigations are well suited for mechanistic understanding, rational XB catalyst design, and the study of intermediates that are unstable when observed experimentally. In this review, we highlight recent computational studies of XB organocatalytic reactions, which provide valuable insights into the XB mode of activation, competing reaction pathways, effects of solvent and counterions, and design of novel XB catalysts.

scholarly journals Selenium phytoremediation study of contaminated soils by Vetiveria zizanioides and Medicago sativa

2015 ◽  
Vol 16 (SE) ◽  
pp. 429-434
Author(s):  
Samaneh Rasooli ◽  
Mojtaba Yousefirad ◽  
Lobat Taghavi
Keyword(s):  
Heavy Metals ◽  
Soil Contamination ◽  
Medicago Sativa ◽  
Contaminated Soils ◽  
Environmentally Friendly ◽  
Factorial Experiment ◽  
Vetiveria Zizanioides ◽  
Great Ability ◽  
Aerial Parts ◽  
Environmentally Friendly Method

With the growth of industry and the increasing consumption of chemicals, their entrance into water, soil and air results in the contamination of environment and consequently the danger that humans face, resulting from heavy metals, is felt more than ever before. Phytoremediation is an environmentally friendly method employing plants for removing pollutants from contaminated soils. The present study was carried out under greenhouse conditions using factorial experiment based on the randomized complete blocks design in three replications in order to analyze the phytoremediation ability of Vetiveria zizanioides and Medicago sativa in soils contaminated with selenium. Five-kilogram pots of Vetiveria zizanioides and Medicago sativa with 0, 10 and 20 mg/Kg selenium in the soil were treated. Sixty days after the treatments, the plants were harvested. The results showed that in both Vetiveria zizanioides and Medicago sativa the effect of selenium in all the studied traits was significant (P<0.01). In both plants, with an increase in the amount of selenium in the soil, the dry weights of the organs decreased and the concentration of selenium in different organs increased. At every level of soil contamination the concentration of selenium in the different organs of Vetiver were higher than alfalfa. Since the transfer and absorption factors in the root and aerial parts of Vetiver were greater than that of Medicago, Vetiver has great ability in absorption and transfer of selenium from soil to shoot in comparison with alfalfa and is a more suitable plant for phytoremediation.

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