The phytoextraction power of Cichorium intybus L. on metal-contaminated soil: Focus on time- and cultivar-depending accumulation and distribution of cadmium, lead and zinc.

This study is focused on the evaluation of the accumulation of Cd, Pb and Zn in five cultivars of Cichorium intybus L. (chicory) which were produced on contaminated agricultural soil. Over a growth period of 211 days, the roots and leaves were collected in four stages and then analyzed by flame atomic absorption spectrometry to measure the concentration and distribution of the target metals in these two chicory organs considering the weather and the nature of the cultivar. For all cultivars, sharp decreases of Pb (from 165 mg kg-1 to 3 mg kg-1), Cd (from 11 mg kg-1 to 5 mg kg-1) and Zn concentrations (from 157 mg kg-1 to 40 mg kg-1) in the roots were highlighted over time. The data collected enabled the calculation of the variation of the bioconcentration factor, the biological absorption coefficient and the translocation factor for Cd, Pb and Zn. These parameters were then correlated with the distribution of the fresh biomass of leaves and roots and several indicators such as chlorophyll content, flavonols, anthocyanin and nitrogen balance index were measured. The study concludes with the discussion on the ability of chicory to clean up contaminated agricultural soil. The current investigation has shown: i) a translocation of Cd (and Zn to a lesser extent) from the roots to the leaves; ii) an increase in the level of anthocyanins with the increase of the metal trace elements concentration in the leaf, while the content of chlorophyll and the nitrogen balance index decrease, which could be linked to the phenomenon of senescence; iii) an ability of the chicory to reduce the bioavailable pool of the three metal trace elements studied, in particular for Cd.

Wheat and ryegrass biomass ashes as effective sorbents for metallic and organic pollutants from contaminated water in lab-engineered cartridge filtration system.

Three plant biomasses (miscanthus, ryegrass and wheat) have been considered for the preparation of five different sorbents evaluated for their potential to sorb cadmium and lead and four emergent organic compounds (diclofenac, sulfamethoxazole, 17α-ethynylestradiol and triclosan) from artificially contaminated water. Lab-created cartridges were filled with each sorbent and all experiments were systematically compared to activated charcoal Norit®. Results from activated charcoal, wheat straw and acidified wheat straw were supported by the Langmuir and Freundlich models. Wheat straw ashes were an excellent metal extractor that exceeded the potential of well-known activated charcoal. Acidified sorbents (wheat and ryegrass) were very effective in eliminating the selected emerging organic contaminants displaying equipotent or superior activity compared to activated charcoal. These results open the way for further in natura studies by proposing new biosource materials as new effective tools in the fight against water pollution.

Star-Shaped Ruthenium Complexes as Prototypes of Molecular Gears.

The design and synthesis of two families of molecular-gear prototypes is reported, with the aim of assembling them into trains of gears on a surface and ultimately achieving controlled intermolecular gearing motion. These piano-stool ruthenium complexes incorporate a hydrotris(indazolyl)borate moiety as tripodal rotation axle and a pentaarylcyclopentadienyl ligand as star-shaped cogwheel, equipped with five teeth ranging from pseudo-1D aryl groups to large planar 2D paddles. A divergent synthetic approach was followed, starting from a pentakis(p-bromophenyl)cyclopentadienyl ruthenium(II) complex as key precursor or from its iodinated counterpart, obtained by copper-catalyzed aromatic Br/I exchange. Subsequent fivefold cross-coupling reactions with various partners allowed high structural diversity to be reached and yielded molecular-gear prototypes with aryl-, carbazole-, BODIPY- and porphyrin-derived teeth of increasing size and length.