Equilibrium data of the exchange of Cu²⁺, Cd²⁺ and Zn²⁺ ions for H⁺ on the cationic exchanger Lewatit TP‐207

Abstract

Equilibrium ion exchange isotherms in aqueous medium of H + /Cu 2+ , H + /Zn 2+ and H + /Cd 2+ on a weak acid resin Lewatit TP-207, at different pH values and at 298 K have been determined in order to assess the possibility of using ion exchange to eliminate heavy metal ions from industrial aqueous liquid streams. The experimental equilibrium data have been satisfactorily correlated using a Langmuir-type empirical equation. It was found that the operating resin capacity with respect to each metal ion increased with increase in solution pH, in accordance with a second-degree polynomial equation. Taking into account the variation of operating capacity with pH, each system exhibited a unique separation factor, namely all the experimental points can be described by a unique isotherm in a dimensionless form. Resin Lewatit TP-207 exhibited the following selectivity order: Cu 2+ > Zn 2+ > Cd 2+ at 298 K.

Treatment of aqueous solutions containing nickel using crandallite‐type compounds

“…A Langmuir‐type empirical equation19 was used to fit the experimental equilibrium data and the data were correlated quite well by Eqn (4): …”

Phenol removal from aqueous solution by adsorption and ion exchange mechanisms onto polymeric resins

“…1 shows the equilibrium data fitted to the Langmuir isotherm at different pHs for three resins. The effect of pH on the equilibrium adsorption can be simulated using an empirical model; this approach is an extension of the classical Langmuir isotherm to model adsorption data at different pHs [24,29]. The maximum loading experimental values and pH can be fitted using an empirical equation…”

Evaluation of chelating ion-exchange resins for separating Cr(III) from industrial effluents

“…The main disadvantage of these processes is the production of solid residues (sludges) with toxic compounds, whose final disposal is usually landfilling. Therefore, the use of alternative processes, such as adsorption [1][2][3], ion-exchange [4][5][6][7][8][9][10][11][12][13], membrane [14,15] and biological [16,17] processes is advisable, in order to protect the environment, as well as for recovering at least one valuable metal.…”