Topic
Cadmium ion binding
About: Cadmium ion binding is a research topic. Over the lifetime, 13 publications have been published within this topic receiving 600 citations.
Papers
1 Aug 1994
TL;DR: Saar and Weber as discussed by the authors proposed an analytical competitive binding equation for heterogeneous surfaces based on a non-ideal local isotherm equation, which includes both lateral interactions and component-specific heterogeneity contributions.
Abstract: Adsorption on heterogeneous surfaces may be influenced not only by the heterogeneity but also by lateral interactions. For multicomponent solutions competition increases the complexity even further. In practice such complex systems frequently occur and to investigate the behavior of these systems it is rather useful to have analytical equations available which can describe the adsorption. Existing analytical mono- and multicomponent binding equations for heterogeneous surfaces are briefly reviewed. These equations are based on a high degree of ideality with respect to both the local isotherm and the affinity distribution for the different components. A new more generally valid analytical competitive binding equation is derived, using a nonideal local isotherm equation. In this local isotherm all component-specific nonideality is incorporated; i.e., it includes both lateral interactions and component-specific heterogeneity contributions. Under these conditions the remaining adsorbate-surface interactions can be characterized by an "intrinsic" affinity distribution that applies for all components. The features of the new equation are discussed and illustrated on the basis of some model calculations. The model is tested in practice using cadmium ion binding to fulvic acid at various pH values (data of Saar and Weber, Can. J. Chem. 57, 1263, 1979). These data cannot be modeled satisfactorily with the classical equation for multicomponent adsorption on heterogeneous surfaces. The newly derived equation gives excellent results.
317 citations
TL;DR: The findings of this study suggest that the sorption of cadmium by dealginate is mainly due to an ion-exchange mechanism, and carboxyl groups are largely responsible for sorption.
Abstract: The ability of dealginated seaweed waste, a waste material derived from the commercial processing of seaweed for alginate production, to remove cadmium from solution was determined. Cadmium sorption was found to be rapid (91% removal within 5 min), achieving a residual concentration of 0.8 mg L-1 after 1-h contact time from an initial solution concentration of 10 mg L-1. The binding of cadmium by dealginate was found to be pH dependent, optimal sorption occurring at around pH 6-8. The mechanism of cadmium ion binding by dealginate was investigated by a number of techniques. Potentiometric titration of the dealginate revealed two distinct pKa values, the first having a value similar to carboxyl groups and the second comparable with that of saturated thiols and amines. Esterification of the dealginate resulted in the subsequent reduction in cadmium sorption (95% to 17%), indicating that carboxyl groups are largely responsible for sorption. Evidence from FT-IR spectra confirmed the presence of carboxyl groups in untreated dealginate, while the number of carboxyl groups was markedly reduced in the esterified sample. Furthermore, the FT-IR spectrum for dealginate was found to be similar to that previously reported for mannuronic acid-rich calcium alginate. Determination of a molar ratio in the displacement of calcium by cadmium on dealginate further supported the presence of an ion-exchange relationship. The ion-exchange constant was calculated to be 0.329 x 10(-6). The speciation of cadmium in solution both before and after sorption was determined by an ion-selective electrode (ISE) technique. The findings of this study suggest that the sorption of cadmium by dealginate is mainly due to an ion-exchange mechanism.
189 citations
TL;DR: Cd2-resistant (CDR) and Zn2+-resistant strains (ZNR) were obtained from subcultivations of Thiobacillus thiooxidans WU-79A and the properties of the proteins were spectrophotometrically similar to those of metallothionein.
24 citations
TL;DR: In this article, a polarographic method of analysis was applied to study cadmium ion binding in carboxymethyl cellulose (CMC) solutions and the results were interpreted according to Oosawa's two phase model of polyelectrolytes.
Abstract: The polarographic method of analysis was applied to study cadmium ion binding in carboxymethyl cellulose (CMC) solutions. Two CMC samples of average degree of substitution 0.80 and 1.14 were selected. The degree of free ions virtually remains constant in wide range of concentrations of CMC solutions and decreases with degree of neutralization. The results are interpreted according to Oosawa's two phase model of polyelectrolytes.
Die Bindung von Cadmiumionen an Carboxymethylcellulose (CMC) wurde polarographisch untersucht. Zwei CMC-Proben mit dem mittleren Substitutionsgrad von 0,80 und 1,14 wurden dazu ausgewahlt. Der Anteil an freien Ionen bleibt uber einen grosen Konzentrationsbereich der CMC-Losungen konstant und steigt mit dem Neutralisationsgrad. Die Ergebnisse werden anhand des Zwei-Phasen-Modells von Oosawa interpretiert.
23 citations
TL;DR: In this article, the use of both slurry and solid-state 113 Cd NMR has been applied to the investigation of the chemical moieties involved in cadmium ion binding to a biosorbent.
9 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2015 | 2 |
| 2014 | 1 |
| 2006 | 1 |
| 2001 | 1 |
| 2000 | 1 |