Removal of heavy metal from wastewater model by using polybenzoxazine-based aerogel as a polymeric ligand exchanger

Abstract

Heavy metals are commonly associated with water pollution; therefore, the removal of heavy metals from wastewater has become a necessity. Polymeric ligand exchangers (PLE) are a class of promising sorbents that absorbs chemicals based on their ligand characteristics rather than ionic charges. In the present study, polybenzoxazine based aerogel is chosen as the polymeric ligand exchanger. Nitrogen donor atoms in polybenzoxazine molecule are used as metal hosting sites. The removal of metal ions is in the following order: Sn²⁺ > Cu²⁺ > Fe²⁺ > Pb²⁺ > Ni²⁺ > Cd²⁺ > Cr²⁺; which is in accordance with the Irving-Williams rule. Additionally, the efficiency of the metal ion removal depends on the amount of absorbents and absorption time while the desorption process is a function of pH, type of solution, and temperature.