Biosorption of lead(II) ions onto nano-sized chitosan particle blended polyvinyl alcohol (PVA): adsorption isotherms, kinetics and equilibrium studies

Abstract

Lead(II) ion is one of the most toxic heavy metal present in the industrial effluents that pose many health hazards to the living environment. The current investigation aimed at synthesizing nano-sized chitosan particles and then blending them with polyvinyl alcohol (PVA) to produce a stable chitosan/PVA composite membrane. This composite proved to be a promising adsorbent for the removal of lead(II) ions from the aqueous solution. The prepared nanoparticles of chitosan were characterized using Transmission electron microscope analysis. The morphological nature and the attachment of lead ions onto the adsorbent were studied using scanning electron microscope analysis. The adsorption ability of chitosan/PVA blend was optimized by varying physical parameters such as pH, adsorbent dose, adsorbate concentration, contact time, and temperature. The maximum adsorption of 96.1% was regarded for an initial concentration of 10 mg/L, adsorbent dose of 0.6  g/100 mL at 30°C. The adsorption kinetics were studied with pseudo-first order, pseudo-second order, Weber and Morris intraparticle diffusion and Boyd kinetic models and was found that the system better fitted the pseudo-second order kinetic model. The desorption of lead(II) ions was done effectively using HCl solution, thereby proving that chitosan/PVA blend can be regenerated and reused effectively for further process of removal.

Keywords:

• Chitosan
• PVA
• TEM
• SEM
• Lead(II) ions