Design and application of zirconium-based coordination polymers for selective capture of copper

Abstract

The heavy metal copper in the wastewater is extremely harmful to human and ecological environment. The new metal coordination polymer (Zr-TPTA) adsorbent is prepared to capture copper ion from aqueous medium. The effects of reaction time, initial concentration of Cu(II) ion, pH value and temperature on adsorption efficiency of Cu(II) ion by Zr-TPTA are studied. The maximum adsorption capacity of Zr-TPTA is 148.32 mg/g at pH 3.0. The thermoisopleth and kinetic data conform to Langmuir and pseudo-second-order models, indicating that the adsorption mode is monolayer chemisorption. The capture of Cu(II) ion on Zr-TPTA surface is a spontaneous exothermic process according to thermodynamic parameter calculation results. The strength of interaction force between adsorbent and Cu(II) ion (15,649 mL/g) shows that the Zr-TPTA adsorbent has selective adsorption for Cu(II) ion. The consecutive adsorption-desorption experiment demonstrates the excellent reusability of Zr-TPTA. The X-ray photoelectron spectroscopy (XPS), zeta potential and density functional theory (DFT) prove that the adsorption mechanism is the complexation reaction of Cu(II) ion with CS and CN groups. This work illustrates the value of self-designed novel metal coordination polymer in adsorbent materials with selective capture of copper ion.