Search results for "Metals"
showing 10 items of 2013 documents
NiO@Ni core shell for electrochemical detection of Hg ions
2018
Heavy metals are considered as one of the most dangerous chemicals for human health. Among heavy metals, mercury is one of the most dangerous one: few ppb of Hg can cause serious damages to brain, heart, lungs and kidney. The Environmental Protection Agency setted the maximum concentration of Hg in water as 2 ppb [1] . Nowadays is very important to develop new and novel sensors for heavy metals that could be cheap, easy to use and for in-situ and real-time analysis and in this context electrochemical sensors are perfect candidates [2] . The more powerful electrochemical tequinique is Square Wave Anodic Strippic Voltammetry (SWASV), a two step techinique were the heavy metals are first depos…
Advances in selective conversions by heterogeneous photocatalysis
2010
Selective photocatalytic conversions are offering an alternative green route for replacing environmentally hazardous processes with safe and energy efficient routes. This paper reports the most recent advances in the application of heterogeneous photocatalysis to synthesize valuable compounds by selective oxidation and reduction.
Combining Membrane and Zero Brine Technologies in Waste Acid Treatment for a Circular Economy in the Hot-Dip Galvanizing Industry: A Life Cycle Persp…
2023
AbstractAn innovative approach of combining membrane and zero brine technologies for a joint treatment of industrial liquid waste is investigated regarding its environmental impacts compared to the existing liquid waste treatment. The object of investigation is the generation of waste acid solution by a hot dip galvanizing plant in Sicily, Italy. The waste acid solution contains hydrochloric acid, iron and zinc, which makes it a hazardous waste according to EU classifications. Environmental impacts are studied for two scenarios in the Tecnozinco hot-dip galvanizing plant in Sicily, Italy: (i) the current process of pickling with linear disposal of waste acid and (ii) the pickling combined w…
Diffusion Dialysis for Separation of Hydrochloric Acid, Iron and Zinc Ions from Highly Concentrated Pickling Solutions
2020
Acid recovery from pickling waste solutions is an important step to enhance hot-dip-galvanizing industry process sustainability. Diffusion dialysis (DD) can be used to separate acids and heavy metals (e.g., iron and zinc) from pickling waters, promoting the circular use of such raw materials. In the present study, a laboratory scale unit operating in batch and a continuous large scale unit, both equipped with Fumasep anionic exchange membranes, were tested. Results obtained show that zinc and iron concentration affect the HCl recovery in opposite ways. Iron chlorides enhance acid recovery, while zinc chlorides considerably tend to diffuse through the membrane because of negatively charged c…
The organic carbon derived from sewage sludge as a key parameter determining the fate of trace metals.
2007
8 pages; International audience; In a sandy agricultural soil of south-west of France, continuously cultivated with maize and amended with sewage-sludge over 20 years, the behavior of three trace metals (Cu, Pb, and Zn) was studied during the sludge applications (1974-1993) and after its cessation (1993-1998). Using the delta13C analysis, the dynamics of different sources of organic matter were followed in order to elucidate the influence of the sludge-derived organic matter on the fate of trace metals in the soil and its particle size fractions. This study revealed that sludge-derived organic matter contributed to the formation of macroaggregates through the binding of preexisting microagg…
Sampling procedure in a willow plantation for chemical elements important for biomass combustion quality
2015
Willow (Salix spp.) is expected to contribute significantly to the woody bioenergy system in the future, so more information on how to sample the quality of the willow biomass is needed. The objectives of this study were to investigate the spatial variation of elements within shoots of a willow clone ‘Tordis’, and to reveal the relationship between sampling position, shoot diameters, and distribution of elements. Five Tordis willow shoots were cut into 10–50 cm sections from base to top. The ash content and concentration of twelve elements (Al, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, Si, and Zn) in each section were determined. The results showed large spatial variation in the distribution of mos…
Environmental reconstruction of Trapani saltmarsh (southwestern Sicily) during the last 80 years. An integrated approach by using benthic foraminifer…
2013
Alkoxysilyl substituted oligo(phenylenevinylene)s: chromophores with reactive side chains
2003
The synthesis and properties of highly luminescent oligo(phenylenevinylene)s (OPV) with curable alkoxysilyl groups are described. Two diethoxymethylsilane moieties are connected directly or through flexible spacers to monodisperse alkoxy-substituted OPVs via hydrosilylation of alkinyl and allyloxy groups, Heck reaction with silylstyrene or condensation of aldehydes with aminopropyl silanes. Hydrolysis of the alkoxysilanes yields silanols condensing to curable three-dimensional networks, thus allowing the transformation of small molecules to transparent and fluorescent films with well-defined chromophores.
Alkoxysilylation of π-systems with extended conjugation—reactive chromophores for organic–inorganic hybrid materials
2004
Luminescent stilbenoid chromophores with diethoxysilane end groups are prepared via Heck reactions. Diethoxysilane-substituted styrenes are used as vinylic components, thus allowing the combined connection of the chromophore to the silane moiety with an extension of the π-system. 1,4-Distyrylbenzenes with a terminal bromine are used as coupling partners. The electrical and optical properties the four-ring OPVs are tuned via substitution with donating alkoxy side chains and electron withdrawing cyanide and a naphthyl-1,2,3-oxadiazole moiety. Hydrolysis yields film forming and luminescent cyclosiloxanes.
Tris- and tetrakis-[oligo(phenylenevinylene)]silanes: synthesis and luminescence behaviour
2002
Abstract The connection of three or four monodisperse oligo(phenylenevinylene)s to a central silicon atom is performed via Wittig–Horner reactions. The terminal rings are substituted with alkoxy side chains. Depending on the ratio of the lengths of the rigid conjugated units and the flexible side chains, transparent films can be obtained from several of these trigonal-pyramidal or tetrahedral molecules. An intense fluorescence in the blue-green region is emitted by molecules of either shape. These compounds are interesting as active materials for electro-optical applications due to their intense fluorescence and improved film forming capability.