The interactions and adsorption mechanisms of ternary heavy metals on boron nitride

Abstract In this work, the interactions and adsorption mechanisms of Cu2+, Cd2+, and Ni2+ on boron nitride (BN) were tested by the simultaneous removal of metal ions from synthetic wastewater. BN was characterized using XRD, SEM, and FTIR spectroscopy. The adsorption differences between BN and the metal ions were explored through comparative studies in a single and ternary system. In the ternary system, adsorption occurs rapidly in the first 2 min for the metal ions, and the affinity order follows Cu2+>Cd2+>Ni2+. However, adsorption behavior changes due to the interaction between metal ions in the ternary system. Cu2+ showed an antagonistic effect on the adsorption of Cd2+ and Ni2+, while Cd2+ and Ni2+ produced a synergistic effect on Cu2+. In addition, the effect of metal ion concentration on the interaction between ions was studied based on a surface response experiment. An increase in Ni2+ or Cd2+ concentrations plays a synergistic effect on the adsorption of Cu2+, while an antagonistic adsorption for Ni2+ occurred with increasing Cu2+ or Cd2+ concentrations. We also discussed the various adsorption mechanisms as complexation, ion exchange, and electrostatic adsorption based on XPS analysis.