Cobalt-based Coordination Polymer (Co-ICP) Microparticles as Preferred Anionic Dye Adsorbent: Synthesis and Dye Adsorption

Development of highly efficient and fast-rate adsorbents has recently attracted intense attention of researchers for wastewater treatment. However, only few investigations have been done on the selective and fast-rate removal of Congo red and methyl orange by coordination polymers. In this work, a new cobalt-based coordination polymer was constructed via simple precipitation method by addition of diethyl ether to the methanolic solution of glutaric acid and cobalt acetate. Two anionic (Congo red and methyl orange) and two cationic (methylene blue and Rhodamine B) dyes were chosen as model targets to examine the adsorption efficiency of the prepared Co-ICP. The experimental data indicated that unlike the cationic dyes, the anionic dyes are excellent targets for adsorption by Co-ICP probably due to stronger electrostatic interactions. Furthermore, it was found that, only after 2 minutes the removal efficiency of Congo red by Co-ICP reaches to 88%. The analytical data confirmed the preservation of the primary structure of the Co-ICP even after 24 h soxhlet washing. The efficiency of obtained Co-ICP for anionic dyes removal partly decreased after four cycles probably due to the occupation of some adsorption sites and reduction of adsorption capacity.