High capacity for selective adsorption of anionic pollutants by a silver(I) 3D cationic supramolecular constructed from a flexible dithione ligand

A new cationic 3D-supramolecular coordination polymer namely, {[Ag3(Prbit)2 (CF3SO3)] [PF6]2}n (Ag-SCP) was designed, synthesized, structurally elucidated by X-ray crystallography and converted into the nano-sized particles in order to use it for further applications. In its asymmetric unit, three different AgI centers with three distinguished coordination geometries were detected. The uncoordinated PF6-anions neutralize the positive charge associated with the complex. The structure was extended by the intermolecular hydrogen bonding interactions to form a 3D supramolecular network structure. The ligand has an anti-gauche conformation. The polymer has a substantial potential for adsorption of organic and inorganic pollutants. Furthermore, as a recyclable promising prototype the nano–sized polymer displays a fast, efficient and reversible adsorption of Cr(VI) from the Cr(VI)-containing aqueous solutions. The influence of various factors such as initial concentration of the Cr(VI) ions, weight of the nano-sized Ag-SCP, pH and contact time on the adsorption efficiency of Cr(VI) were examined by the central composite design (CCD) method. Under the optimum conditions and desirable function value of 1.0, the adsorption percentage of Cr(VI) ions was to be 97%. Regression analysis with an R2 value of 0.99 indicates a satisfactory correlation between the obtained and predicted data. By virtue of these benefits, the presented supramolecular exhibits a high capture yield. Additionally, the adsorption of Cr(VI) by the nano Ag– SCP via anion exchange mechanism was dependent on the nature of the cationic network. Furthermore, the adsorbent exhibits a good capacity and selectivity for the adsorption of anionic dyes from the aqueous solutions.