Removal of Lead(II) ions from aqueous solutions using biocompatible polymeric nano-adsorbents: A comparative study

Low-cost and biocompatible chitin nanofiber and chitosan nanoparticle as natural polymers synthesized successfully by means of a mechanical and a chemical procedure respectively. The surface properties and size of chitin nanofibers (CNFs) and chitosan nanoparticles (CNPs) were characterized using a scanning electron microscope (SEM). CNF and CNP were utilized for separation of lead(II) metal ions from aqueous solution, and the influence of effective factors were investigated. It was found that both adsorbents can adsorb lead ions from the solution effectively, but sorption efficiency for CNP at all the stages was greater than CNF. Furthermore, the results of corresponding equilibrium data with adsorption isotherms revealed that CNF and CNP are more compatible with Freundlich and Langmuir adsorption isotherms respectively. It shows that, for CNF, adsorption process occurs as a heterogeneous and multi-layer process, while for CNP, adsorption process is predicted to befall as a homogenous and single-layer process. At the end kinetics and thermodynamic studies were performed for both Nano-adsorbents.