Search results for " solution"
showing 10 items of 3084 documents
Cadmium and Zinc Adsorption onto Activated Carbon: Influence of Temperature, pH and Metal/Carbon Ratio
1996
The adsorption characteristics of cadmium and zinc onto a granular activated carbon were studied. Cadmium and zinc removals increased on raising pH and temperature, and decreased on raising the molar metal/carbon ratio. The adsorption processes were modelled using the surface complex formation (SCF) Triple Layer Model (TLM) with an overall bidentate species. A dependence of the SCF constant on pH, the molar metal/carbon ratio and temperature was observed, and a correlation for log K ads was determined. The SCF model successfully predicted cadmium and zinc removals.
Sorption of thallium(I) ions by peat.
2013
The increasing industrial use of thallium has raised the need for removal of this highly toxic element from wastewater. Thallium is more toxic than cadmium, copper, zinc, lead and mercury and as it is easily accumulated in humans, animals and plants, it poses a threat to both the environment and human health. Peat has been used as an effective, relatively cheap and easily available sorbent to treat waters containing heavy metals. In this study, peat was characterized and used as sorbent for the removal of Tl(I) ions from aqueous solution. The effect of initial Tl(I) concentration, pH, contact time, temperature and ionic strength was studied in batch mode. The maximum sorption capacity of pe…
Metal speciation in biological fluids — a review
1996
The literature on the speciation of metal ions in biological fluids is comprehensively reviewed. Critical examination on this subject reveals that major work has been done in blood and urine. Speciation in materials like milk has not yet been widely studied. On the other hand, only few references could be found on sweat, saliva, cell lysate, cerebrospinal, seminal, tear and bronchoalveolar fluids. The topics studied for these fluids were mainly the speciation of arsenic, mercury, aluminium and selenium. Work on the speciation of other elements like zinc, chromium, cadmium, lead, copper, iron etc. have also been carried out in such matrices. The present literature survey includes also a crit…
Molecular Self-Assembly Versus Surface Restructuring During Calcite Dissolution.
2016
Organic additives are known to alter the mineral-water interface in various ways. On the one hand, organic molecules can self assemble into ordered structures wetting the surface. On the other hand, their presence can affect the interfacial morphology, referred to as surface restructuring. Here, we investigate the impact, of a class of calcium-complexing azo dyes on the dissolution of calcite (10.4) using high-resolution atomic force microscopy operated in aqueous solution, with a focus on the two constitutional isomers Eriochrome Black T and Eriochrome Black A. A very pronounced surface restructuring is observed in the presence of the dye solution, irrespective of the specific dye used and…
Three-dimensional hydration layer mapping on the (10.4) surface of calcite using amplitude modulation atomic force microscopy
2014
Calcite, the most stable modification of calcium carbonate, is a major mineral in nature. It is, therefore, highly relevant in a broad range of fields such as biomineralization, sea water desalination and oil production. Knowledge of the surface structure and reactivity of the most stable cleavage plane, calcite (10.4), is pivotal for understanding the role of calcite in these diverse areas. Given the fact that most biological processes and technical applications take place in an aqueous environment, perhaps the most basic - yet decisive - question addresses the interaction of water molecules with the calcite (10.4) surface. In this work, amplitude modulation atomic force microscopy is used…
A new simple approach to evaluate pedogenic clay transformation in a Vertic Calcisol
2006
The aim of this study is to characterize the pedogenic clay minerals by using simple approach: Mixing mineralogical and geochemical findings. The fine clay fractions (< 0.1 μm) of a Vertic Cambisol profile were studied by means of X-ray diffraction (XRD), infrared spectroscopy (FTIR) and cation exchange capacity (CEC). Qualitative and quantitative mineralogical compositions of the clay mixture were determined. Moreover, chemical equilibria and thermodynamic stabilities of minerals (calcite, gypsum, kaolinite, smectites and illites) were studied using results of ionic activities obtained from total concentration of various aqueous species in water extracts from soil-saturated pastes. XRD ana…
Zirconium and hafnium fractionation and distribution of Rare Earth Elements in neutral–alkaline waters: Case study of Lake Van hydrothermal system, T…
2021
International audience; We investigated the distribution of Zr, Hf, and rare earth elements (REE) as the sum of lanthanides plus Y in the hydrothermal system in the Lake Van area of south-eastern Turkey. This system is characterised by water with variable pH in alkaline conditions resulting from hydrothermal CO2 upraise and neoformation of calcite minerals in near equilibrium with the interacting waters. Zr, Hf, and REE determinations were carried out for aqueous phases and suspended solids in lake water and surrounding thermal springs. We found that dissolved Hf is partitioned relative to Zr during calcite formation and that such fractionation is a function of the Ca2+ activity in warm wat…
In-situ suspended aggregate microextraction: A sample preparation approach for the enrichment of organic compounds in aqueous solutions.
2015
Abstract This work presents in-situ suspended aggregate microextraction (iSAME) as a new and expedient sample preparation method. This new concept capitalizes on the general principles of in-situ solvent formation microextraction, in the sense that extraction is carried out in a supramolecular aggregate phase, which is formed in-situ in the sample through one-step process involving ion-association between a cationic surfactant and a benzene sulfonic acid derivative. The suspended aggregate containing the analytes is then collected in the form of a thin-film on the surface of a common filter paper by suction filtration. The entrapped analytes are released by completely dissolving the thin-fi…
Salso-bromo-iodine thermal water: a nonpharmacological alternative treatment for postnasal drip-related cough in children with upper respiratory trac…
2018
Postnasal drip (PND)-related cough is a very common symptom in patients with upper respiratory tract infections (URTis). At present, there is not a standard treatment for postnasal drip and postnasal drip-related cough. The aim of this pilot study was to evaluate the efficacy of a specific salso-bromoiodine thermal water containing hyaluronic acid and grapefruit seed extract (SBI-H-GSE) comparing it with a normal saline solution in children with URTis who refer PND-related symptoms. The study was randomized, single-blind, and controlled. Study group (75 children) was treated with SBI-HGSE and control group (65 children) was treated with a normal saline solution; both compounds were administ…
Desferrioxamine as an appropriate chelator for 90Nb: Comparison of its complexation properties for M-Df-Octreotide (M=Nb, Fe, Ga, Zr)
2014
The niobium-90 radioisotope ((90)Nb) holds considerable promise for use in immuno-PET, due to its decay parameters (t½ = 14.6h, positron yield=53%, Eß(+)(mean) = 0.35 MeV and Eß(+)(max) = 1.5 MeV). In particular, (90)Nb appears well suited to detect in vivo the pharmacokinetics of large targeting vectors (50-150 kDa). In order to be useful for immuno-PET chelators are required to both stabilize the radionuclide in terms of coordination chemistry and to facilitate the covalent attachment to the targeting vector. Different chelators were evaluated for this purpose in terms of radiolabelling efficiency and stability of the radiolabelled Nb(V) complex and in order to determine the most suitable…