Metal ions binding capacities

Tables Metal ion binding capacity of linear PCEAC-Gly, PCEAC-Ala, and PCEAC-Lys [275]...

Copolymerisation of N-vinylpyrrolidone or acrylic acid with other functional monomers such as allylic compounds and vinyl ethers results in the formation of polymers widi excellent solubility properties and metal-ion binding capacities ... 

Studies of metal ion binding [Cu(II), Ni(II), Fe(III), Mn(II), Ag(I), Au(III), Pd(II), Pt(II), Ru(III)] by different OH- and NHj-terminated PAMAM derivatives in aqueous solution show that these metal ions are bound to the branching tertiary amine functions with high capacity, with the observed uptake clearly dependent on the number of generations and on the pH. In the case of amine-terminated derivatives, the metal ions can also bind to these end groups, resulting in a further increase in uptake [8]. 

The effect of pH on heavy metal ion adsorption capacity was studied by previous researchers using the shake flask experiments. Eric and Roux used the shake flask experiment to study the influence of pH on the heavy metal ion binding onto a fimgus-derived bio-sorbent in the year, 1992. Also the evaluation of the effect of the hydrochloric acid concentration on the adsorption of platinum group metal ions onto chemically modified chitosan was done by Inoue et al., using the shake flask experiment [85]. Depending upon the type of P complexation with the surface such as monodentate, bidentate mononuclear, and bidentate binuclear the phosphorus desorption is potentially controlled. These complexes can be either non protonated or protonated depending on the suspension pH [184]. 

About half of the dissolved organic carbon may appear in humic or fulvic acids. These are high-molecular weight organic compounds of a composition which is somewhat uncertain. They contain aromatic hydroxyl and carboxyl groups which have the ability to bind to metal ions. Rivers and estuaries typically contain 10 mg/liter of acid with an exchange capacity of 5-10 mmol/g, mainly due to carboxylic... 

Interactions studies between some divalents metal ions and pectins from citms and sugar-beet revealed that the chemical structure of the latter, namely the presence of acetyl functions, induces differences of binding process whereas the scale of selectivity was not affected. Some further studies could be carried out on the correlation between the binding mode and the degree of acetylation. Lastly, pectins showed a clear scale of selectivity towards heavy metals with high capacities of binding which make them suitable to be used in waste-waters depollution. 

The complexing of chitosan and its basic derivatives with anionic substances is paralleled by compatibility with cationic and nonionic compounds. Similarly, the anionic derivatives of chitosan show complex formation with cationic agents and are compatible with anionic and nonionic compounds. The capability of these chitosan derivatives to complex with certain metal ions, notably those of the transition series, is also important, having possibilities for the removal of metal salts from effluent. The hierarchy in terms of binding capacity is Cr(III) < Cr(II) < Pb(II) < Mn(II) < Cd(II) < Ni(II) < Fe(II) < Co(II). 

It is known that part of this process involves the 80-kDa blood serum protein transferrin that tightly binds and transports two ferric iron ions. Because the iron binding uses only 30% of transferrin s metal binding capacity, it has long been thought to bind and transfer other metal ions (including perhaps chromium) in vivo, although this has not been demonstrated by experiment. 

The capacity of inositol orthoformate derivatives 124 and 125 for binding to alkali metal ions was studied by electrospray ionization mass spectrometry (ESI-MS) gas-phase measurements <2001JOC8629>. The [5.5.5]-iono-phore 125 n = 3) possessed the highest Li /Na selectivity and the best affinity for Li. The results obtained proved to be in agreement with the size-fit concept. Other factors which influence the complexation are the orientation of the oxygen atoms, which are able to bind to metal, the basicity, and the polarizability of the heteroatoms around the perimeter of the binding cavity. 

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