Selective Adsorption of Anionic Dyes Using New Three-Dimension Ag(I) Coordination Polymer

Abstract

We are reporting herein a new ligand 2,2,4,4,6,6-hexakis(2-ethyl-1H-imidazol-1-yl)-cyclotriphosphazene (EtIm-Cp) and its Ag(I) coordination polymer (1). EtIm-Cp was characterised by standard spectroscopic techniques, 1H NMR, 31P NMR, and mass spectrometric analysis. The compounds were characterized using single crystal X-ray diffraction. Ligand, EtIm-Cp, in complex 1 form a 3D coordination polymer by joining three Ag(I) ions, resulting in a kappa 3N coordination mode. Topological analysis confirms that complex 1 shows a three-connected unimodal net with the point symbol of {103}. In order to adsorb three cationic and three anionic organic dyes in aqueous environments, coordination polymers were used. Experiments demonstrate that 1 shows no adsorption behavior towards cationic dyes methylene blue (MB) Rhodamine B (RhB), and Astrazon blue (AB) but it does remove the anionic methyl orange (MO), tartrazine (E102), and sunset yellow (SY) from water. Furthermore, complex 1 completely removed selectively anionic dyes from the anionic/cationic dye mixture. Surface charge values obtained from zeta potential measurements confirm that anionic dyes are adsorbed onto the surface of the complex 1. According to PXRD analysis, there was no deterioration in the chemical structure of the compound after adsorption.