Synthesis of Di-amine Functionalized Lignin Derivative and Its Removal Ability for Heavy Metal Ions

Abstract

In this study, di-amine functionalized lignin (DAL) was prepared by a two-step reaction and its adsorption behavior for metal ions (Pb(II), Cu(II) and Cd(II)) was investigated. The chemical structural analysis of DAL by FT-IR, XPS and 1H NMR confirmed that the di-amine groups were successfully introduced into lignin. The prepared DAL exhibited enhanced molecular weight, and thermal stability. For adsorption behavior, DAL has a higher adsorption capacity for cationic heavy metal ions under neutral conditions than acidic conditions. In addition, it was confirmed that adsorption capacity of Pb(II) ions by DAL was better than those of Cu(II) and Cd(II) ions. This is due to an adsorption mechanism in which DAL introduced with a lone pair of N-functional group in lignin is chelated with metal ions, which showed that DAL was a promising adsorbent for wastewater treatment. Therefore, it was suggested that the lignin-based di-amine derivative prepared in this study could provide an opportunity to increase the utility of novel lignin-based biomaterials as a low-cost biosorbent.