Thiosemicarbazide-modified/ion-imprinted phenolic resin for selective uptake of cadmium ions

Abstract

Cd(II)-imprinted Cd(II) resin obtained from a thiosemicarbazide derivative of salicylic acid was prepared and evaluated for selective uptake of Cd(II) ions. In the beginning, the thiosemicarbazide derivative of salicylic acid (H2TCS) was developed as a functional ligand that was then coordinated with Cd(II) ions to obtain the Cd-complex [CdTCS(H2O)3]. After the full investigation of the ligand and its complex, they copolymerized with resorcinol in presence of formalin, and the obtained resinous material was eluted with 0.1 M HNO3 solution to extract the polymer incorporated Cd(II) ions and finally produce the Cd(II) ions selective Cd-RTCS sorbent. The maximum cadmium ions capacity by the Cd-RTCS reached 164 ± 1 mg/g, which could be a relatively high and promising value. Also, the adsorption isotherms were interpreted better with the Langmuir model. In addition, the Cd(II) sorption using Cd-RTCS was tested in a competitive medium of Pb(II), Ni(II), Zn(II), and, Cu(II) ions and the results indicated a considerable selectivity toward the Cd(II) ions over the coexisted metals.