Sustainable synthesis of PAR-modified chitosan for selective lead(II) separation from copper(II) in water

Abstract

Elevated concentrations of lead and copper in the natural environment, primarily due to polymetallic ore processing, underscore the urgent need for advanced remediation strategies. The chemical similarity between these metals complicates their selective separation during water treatment. Chitosan-based adsorbents, which are both biodegradable and environmentally benign, offer a promising approach. In this study, a derivative of the 4-(2-pyridylazo)resorcinol (PAR) was synthesised and used in a sustainable mechanochemical process to modify chitosan. The modified material was characterised by 13C NMR and FTIR spectroscopy, and its adsorption properties were evaluated using ICP-AES. The PAR-derivative-modified chitosan exhibited high adsorption efficiency for lead ions (95.4%) and lower efficiency for copper ions (38.3%). These findings indicate that chitosan-based materials can be effective for heavy metal adsorption removal and possess significant potential for the selective separation of Pb(II) from Cu(II).