Synthesis of glutamic acid-based coordination polymer for dye removal from aqueous solution

In this work, a cost-effective and eco-friendly coordination polymer (Zr-CP) was synthesized through the combination of natural amino acids as ligands with Zr 4+ metal cation under aqueous conditions at room temperature and used for the treatment of dyeing wastewater. The results showed that Zr-CP exhibited a high adsorption potential for Congo red (CR) in various simulated dyeing effluents. It possesses a theoretical adsorption capacity for CR up to 381.68 mg/g at room temperature 25 ℃ in pH 7, probably due to the abundance of primary amino functional groups in its chemical structure. The thermodynamic analysis indicates that the use of Zr-CP as an adsorbent in the wastewater purification process endothermic and spontaneous in nature. Among the tested isotherms, the Langmuir model was found to best fit the equilibrium data, with a coefficient R 2 value of 0.98. Besides, the adsorption behavior of this bio-based coordination polymer for Congo red was found to adhere to the pseudo-first-order kinetic equation with higher correlation coefficient R 2 of 0.98. Moreover, Zr-CP showed outstanding cycle performance and sustained a high dye removal efficiency even after five reuses. These results indicate that Zr-CP, a biologically derived coordination polymer, offers the advantages of affordability and efficiency, making it a promising adsorbent for the removal of organic pollutants from printing and dyeing effluents.