Equilibrium and Kinetic Study of Lead and Copper Ion Adsorption on Chitosan-Grafted-Polyacrylic Acid Synthesized by Surface Initiated Atomic Transfer Polymerization.

In this work, we synthesized chitosan grafted-polyacrylic acid (CS--PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto the CS--PA surface. Adsorption equilibrium studies indicated that pH 4.0 was the best pH for the adsorption process and the maximum adsorption capacity over CS--PA for Pb ions was 98 mg·g and for Cu it was 164 mg·g, while for chitosan alone (CS), the Pb adsorption capacity was only 14.8 mg·g and for Cu it was 140 mg·g. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data and besides, pseudo-second-order model was suitable to describe kinetic results for the adsorption process, demonstrating a larger kinetic constant of the process was larger for Pb than Cu. Compared to other adsorbents reported, CS--PA had comparable or even superior adsorbent capacity and besides, all these results suggest that the new CS--PA polymers had potential as an adsorbent for hazardous and toxic metal ions produced by different industries.