Novel anthracene and pyrene containing Cd(II)-based coordination polymers for adsorptive removal of toxic dyes from aqueous medium

Abstract

In the present work, we have synthesized two new one- and two-dimensional Cd(II) coordination polymers (CPs), formulated as [Cd(L1)(Formamide)2]n (1) and [Cd2(L2)2(MeOH)2]n (2), by the solvothermal reactions of Cd(NO3)2·4H2O with the anthracene and pyrene group bearing carboxylic acids 5-{(anthracen-9-ylmethyl)amino}isophthalic acid (H2L1) and 5-{(pyren-1-ylmethyl)amino}isophthalic acid (H2L2), respectively. The newly synthesized CPs were characterized by FT-IR, elemental, thermogravimetry and single-crystal and powder X-ray diffraction analyses. The single-crystal X-ray diffraction analysis demonstrates that CPs 1 and 2 have one-dimensional double chain and two-dimensional structures, respectively. These novel CPs were employed for the adsorptive removal of various toxic cationic and anionic organic dyes in aqueous medium. Both CPs are highly effective for the removal of cationic dyes in comparison to anionic ones. However, the two-dimensional pyrene group containing CP 2 shows a higher efficiency (removal efficiency of 75–97 %) in removing three different 6 × 10−5 M cationic dyes. In addition, the adsorption kinetics and isotherms for both CPs were determined. An insight into the removal of the organic dyes is provided by in silico studies. Moreover, the stability and recyclability of both CPs were tested under adsorption conditions.