a simple method has been developed for the preconcentration of copper(ii) based on the adsorption of its modified nano polyacrylonitrile fiber. modified nano polyacrylonitrile fiber (panf) was prepared by adding of acrylic fibers to msethanolamine (mma) with different concentration solutions. the stability of a chemically modified nano polyacrylonitrile fiber especially in concentrated hydrochl...

Optimization of Cd (II), Zn (II) and Cu (II) biosorption from contaminated water were performed as function of parameters (pH, contact time, initial metal ions concentration and yeast dose). The experimental results showed that the highest equilibrium adsorption capacity at the optimum pH were 8.5 for Cd (II) and 6 for Zn (II) and 6 for Cu (II). Optimum pH values were carried out to evaluate ot...

The properties of purified capsular polysaccharide from the cyanobacterium Microcystis flos-aquae C3-40 were examined by capillary viscometry. Capsule suspensions exhibited similar viscosities between pH 6 and 10 but were more viscous at pH <=4 than at pH 6 to 11. At pH 7, a biphasic effect of metal ion concentration on capsule viscosity was observed: (i) capsule viscosity increased with increa...

Optimization of Cd (II), Zn (II) and Cu (II) biosorption from contaminated water were performed as function of parameters (pH, contact time, initial metal ions concentration and yeast dose). The experimental results showed that the highest equilibrium adsorption capacity at the optimum pH were 8.5 for Cd (II) and 6 for Zn (II) and 6 for Cu (II). Optimum pH values were carried out to evaluate ot...

bioremediation of heavy metals remains a major challenge in environmental biotechnology. biosorption is a novel technique for decreasing metal ion content in the waste water. biosorption experiments for cu (ii) were investigated in this study using bacteria isolated from the industrial effluent. the results showed that the dead cells of pseudomonas sp. were an efficient adsorbent of cu (ii). fo...

BACKGROUND Any metal placed in a biological environment undergoes corrosion. Thus, with their large metallic surfaces, TKA implants are particularly prone to corrosion with subsequent release of metal ions into the human body which may cause local and systemic toxic effects and hypersensitivity reactions, and increase cancer risk. To address this problem, a new 7-layer zirconium coating develop...

The influence of the ligand/metal ion concentration ratio on the shape, peak current and peak potential of curves obtained by anodic stripping voltammetry (a.s.v.) at the hanging mercury drop electrode is described, particularly with respect to the use of a.s.v. for speciation of metal ions at very low concentrations as is often found in natural waters. The lead(II)/triethylenetetramine system ...

Evidence for a two-metal ion mechanism for cleavage of the HH16 hammerhead ribozyme is provided by monitoring the rate of cleavage of the RNA substrate as a function of La3+ concentration in the presence of a constant concentration of Mg2+. We show that a bell-shaped curve of cleavage activation is obtained as La3+ is added in micromolar concentrations in the presence of 8 mM Mg2+, with a maxim...

Phosphatidylcholine vesicles harboring the lipophilic metal ion carrier A23187 in the bilayer and encapsulating ethylenediamine tetraacetic acid (EDTA) exhibit broadly varied, pH-dependent affinity for Cu2+, Pb2+, Cd2+, and Ca2+ at micromolar levels. Initial rates of uptake by these metal-sorbing vesicles (MSVs) is strongly dependent on the metal ion affinity of A23187 and the dissociation rate...

There are concerns that tooth bleaching agents may adversely affect dental materials. The aim of this study was to test the hypothesis that increasing concentrations of hydrogen peroxide (HP) are more effective than water at increasing metal ion release from two typical dental casting alloys during bleaching. Discs (n = 28 for each alloy) were prepared by casting and heat treated to simulate a ...