Synthesis of ion-imprinted polymers based on chitosan for high selectivity of La(III), Ce(III) and Sm(III) via solid phase extraction

Abstract

Lanthanide metal ions are extremely important to the development of economy and technology; however they are difficult to separate because of their chemical similarities. Polymers imprinted with ions have become a promising platform to explore possible solutions to this problem in recent years. The purpose of this work is to develop a new specifically designed IIPs material for separating lanthanide ions (La(III), Ce(III), and Sm(III)) based on chitosan (CS) and polyvinylpyrrolidone (PVP). Tartaric acid, 0.25 M, was used to leach the lanthanide template ion from the Ln(III)IP-CS/PVP particles with the capability of selective extraction. As a model, properties of La(III)IP-CS/PVP (both un-leached and leached) were investigated by using FT-IR, XRD, EDX, SEM, TEM, surface area and TG-DTA measurements. A batch-type experiment has been used to investigate the effect on separation of a variety of parameters such as pH of the solution, time of contact, and ion concentration. Various Ln(III)IP-CS/PVP were found to have adsorption capacities of 39.34, 38.24, and 40.51 mg/g for La(III), Ce(III), and Sm(III). In regard to La(III)IP-CS/PVP, adsorption was analyzed using kinetic and isotherm models. In the presence of interfering ions, such as La3+, Ce3+, Sm3+, Nd3+, Dy3+, Ho3+, Er3+, Eu3+, Pr3+, Cs+, Zr4+, Ni2+, Co2+ and Cd2+, the selectivity behavior of La(III), Ce(III) and Sm(III)IP-CS/PVP was investigated. The target lanthanide ion was selected exceptionally well. A study of the regeneration and reusability of the materials found no significant decrease in the adsorption efficiency after five cycles (>80%). For La(III) ions, a breakthrough curve was constructed using La(III)IP-CS/PVP. An evaluation of the applicability of Ln(III)IP-CS/PV for the separation of La(III), Ce(III) and Sm(III) from Abu-Tartur phosphate rock was conducted.