Equilibrium and Kinetic study of lead and copper ions adsorption on Chitosan-grafted-poly acrylic acid synthesized by Surface-initiated Atomic Transfer Polymerization

Abstract

In this work, we synthesized chitosan grafted-poly acrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto CS-g-PA surface. Adsorption equilibrium studies indicated pH 4.0 as the best pH for the adsorption process, while the maximum adsorption capacity for Pb2+ ions was 98 mg*g-1 and for Cu2+ was 164 mg*g-1, higher adsorption capacities than chitosan alone (CS), where Pb2+ was only 14.8 mg*g-1and Cu2+ was 140 mg*g-1, respectively. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data. All these results suggest that the new CS-g-PA polymers had potential as adsorbent for hazardous and toxic metal ions produced by different industries.

Chemical Modification of Chitosan for Removal of Pb(II) Ions from Aqueous Solutions

“…The adsorption capacity increased quickly in the first half, and after this time it increased more slowly, achieving the equilibrium at 120 min. The equilibrium is achieved more quickly than in the other reported adsorption processes with lead ions, for example, onto chitosan-grafted-poly acrylic acid (te = 240 min) [33] and, respectively, more than 5 h onto chitosan impregnated granular activated carbon [26]. For example, with the adsorption of lead onto chitosan-grafted-poly acrylic acid, equilibrium was achieved after 4 h, and with lead and chitosan impregnated granular activated carbon, the time was more than 5 h. The linear plots of the kinetic model studied are presented in Figure 10.…”

“…The linearized Langmuir isotherm represented by the Equation ( 5) suggests that the lead adsorption onto modified (ChitPNi) chitosan occurs as a monolayer covering the adsorbent surface [31][32][33].…”

“…If the surface of the adsorbent is heterogeneous, the equilibrium data will present a good fit for the linearized form of the Temkin isotherm model, which is given by Equation (7), suggesting that the heat of adsorption decreases during the adsorption process [31][32][33].…”

“…The modelling of the experimental data according to the linearized form of the Dubinin-Radushkevich (Equation ( 8)) lead to the obtaining of the mean sorption energy E, which is given by Equation ( 9), which indicates whether the type of adsorption process is physical or chemical [31][32][33].…”

“…which is given by Equation ( 9), which indicates whether the type of adsorption process is physical or chemical [31][32][33].…”