Cobalt-benzene-1,4-dicarboxylic acid coordination polymer for efficient removal of anionic and cationic dyes

Dye removal from wastewater is an important research area due to the stability, toxicity, and potential carcinogenic properties of dyes. Herein, cobalt-benzene-1,4-dicarboxylic acid (Co-BDC) coordination polymer was precipitated from DMF solution of cobalt acetate and benzene-1,4-dicarboxylic acid (BDC) at room temperature. EDX, XPS, ICP-OES, and elemental analyses confirmed the composition of the prepared coordination polymer. SEM image showed microparticles with 200–400 nm. Physical adsorption of Congo red (CR) and methyl orange (MO) as anionic and methylene blue (MB) and malachite green (MG) as cationic dyes with Co-BDC was investigated. The experimental data exhibited higher removal efficiency of Co-BDC towards anionic rather than cationic dyes probably due to its stronger π-π stacking and electrostatic interactions. The removal efficiency of Co-BDC towards CR reaches 84% only after 2 minutes. The XRD and FT-IR analyses confirmed the preservation of the Co-BDC structure even after a long time. The removal efficiency of the prepared Co-BDC toward anionic dyes remained unchanged after two cycles and showed minor loss after three and four cycles. Therefore, the strategy of selecting adsorbents based on the structural properties is efficient for designing and preparing high-performance adsorbents.