Chitosan and gum arabic nanoparticles for heavy metal adsorption

Chitosan (CT) is a polysaccharide with the ability to adsorb metals on its surface. In this work, CT-based nanoparticles (NPs) are produced by complex formation with gum arabic (GA) to increase their adsorbent potential for removal of heavy metals in aqueous medium. Adsorption efficiency is evaluated as a function of NP composition and polysaccharide concentration. NPs are sized from 250 to 375 nm at a zeta potential up to -25 mV, suggesting stability to adsorb metals. In particular, CTGA56 and CTGA80 NPs adsorbed a substantially higher amount of copper ions than pure CT. Adsorption kinetics studies showed that the reaction process followed a pseudo second-order model and the adsorption isotherm results fit a Langmuir model, highlighting the monolayer adsorption process with prominent adsorption capacity. These findings indicate the adsorbent potential of CTGA NPs and suggest that these particles can be used for removal of metal ions from contaminated water sources.