Preparation of Triethylenetetramine-Functionalized Adsorbents for Selective Adsorption of Copper and Zinc Ions

Abstract

Selective adsorption of a target adsorbate is critical in adsorbent performance evaluation, and is of great importance in industrial applications. In this study, the selective adsorption of copper and zinc ions was investigated with the polyamine-functionalized polymeric adsorbents. The adsorbent was prepared by amination of crosslinked poly (glycidyl methacrylate) (PGMA) with triethylenetetramine (TETA). The influencing factors including reaction time and TETA content during adsorbent synthesis were investigated. The prepared adsorbents (P-TETA) was used to study the adsorption selectivity toward copper and zinc ions in single species system (when only one metal ion is present) and binary species system (when both metal ions are present). Both the pH effect and the adsorption isotherm were examined in single and binary species system. It was found that both Cu and Zn ions would be adsorbed onto P-TETA in significant amount in single species system at higher pH values. However, in binary species system with high initial concentrations for both Cu and Zn ions, Cu ions would be selectively adsorbed onto P-TETA, with insignificant amount of Zn ion adsorbed. The higher coordination constant (in Log K form) of Cu-TETA coordination than Zn-TETA coordination was identified as the major mechanism for the selective adsorption of Cu over Zn ions with P-TETA adsorbents.