Sorption of Pb(Ⅱ), Cd(Ⅱ) and Zn(Ⅱ) performed with the use of carboxyphenylresorcinarene-impregnated Amberlite XAD-4 resin

摘要

A study on the adsorption characteristics of Pb(Ⅱ), Cd(Ⅱ) and Zn(Ⅱ) cations onto carboxyphenylresorcinarene-impregnated resin in batch and fixed bed column systems has been conducted. Results of the batch and fixed bed column systems confirm that impregnated resin is a good adsorbent for Pb(Ⅱ) and a poor one for Cd(Ⅱ) and Zn(Ⅱ) ions. Solid phase extraction (SPE) of Pb(Ⅱ), Cd(Ⅱ) and Zn(Ⅱ) was conducted in batch system under various pH, interaction times, and metal concentrations. It was found that SPE of Pb(Ⅱ) was optimal at pH 6.5 at contact time of 60 min, and at initial Pb(Ⅱ) concentration equal to 10 mg/L. The extraction capacity for Pb(Ⅱ) in the batch system was 107.6 mg/g, i.e. 99.7%. On the other hand, the SPE of Cd(Ⅱ) and Zn(Ⅱ) under optimal conditions has shown much smaller extraction capacities. Selectivity order of extracted metal ions was Pb(Ⅱ) Cd(Ⅱ), Zn (Ⅱ). The values of correlation coefficients (R~2) indicated that the Langmuir isotherm model well-described the sorption equilibrium. Application of Temkin sorption model to the experimental data revealed that the mechanism of adsorption of metal ions onto resorcina-rene-impregnated resin was physisorption. The column test also confirmed the results of batch tests and showed that the total uptake of Pb(Ⅱ) was 104.4 mg/g. The carboxyphenyl resorcinarene derivative-impregnated resin has been found efficient and easily regenerative and can be used several times.