Carbonaceous sulfur-containing chitosan–Fe(III): A novel adsorbent for efficient removal of copper (II) from water

A novel adsorbent of carbonaceous sulfur-containing chitosan–Fe(III) was developed for copper (II) removal from water. This adsorbent showed an excellent performance in copper removal due to its fast kinetic behavior, high adsorption capacity and relatively good ability to resist acidic conditions. The adsorption of Cu2+ was observed to be fast in the beginning 2.5 min followed by a slower adsorption process, and eventually equilibrium was reached in about 15 min. The Cu2+ adsorption isotherm was well described by Langmuir model. The calculated adsorption capacity of carbonaceous sulfur-containing chitosan–Fe(III) for Cu2+ was up to 413.2 mg/g, which is higher than most (of the) values reported before. The main mechanism of Cu2+ adsorption is chelation with the O as well as small contribution from S atoms in the molecules. During the preparation process of this adsorbent, the majority of the sulfur binds with iron. Both sulfur and Fe contribute to the formation of a stable and regular matrix with macropores, which increase the access to the adsorption sites for Cu2+. Overall, this study indicates that there is potential to use carbonaceous sulfur-containing chitosan–Fe(III) to remove Cu2+ from water in practical applications.