Adsorption performance of a polysaccharide composite hydrogel based on crosslinked glucan/chitosan for heavy metal ions

Glucan/chitosan (GL/CS) hydrogels as adsorbents for heavy metal ions in wastewater treatment were synthesized by ultrasound-assisted free radical polymerization. The samples were characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). In the study of adsorption process, the effects of temperature, acidity and alkalinity, dosage of adsorbent, adsorption time and concentration of heavy metal ions on adsorption behavior of GL/CS adsorbent in simulated wastewater were discussed. On the basis of the above research, the adsorption thermodynamics, adsorption kinetics and adsorption mechanism were also studied. When the temperature was 20 °C, the pH value was 7.0 and the amount of adsorbent was 0.01 g, the results showed that the adsorption capacities of GL/CS hydrogels for Cu2+, Co2+, Ni2+, Pb2+ and Cd2+ were 342 mg g−1, 232 mg g−1, 184 mg g−1, 395 mg g−1, 269 mg g−1, respectively. The fitting results of the isothermal models, the kinetic models and thermodynamics of the experimental data of the ion adsorption process show that the adsorption of heavy metal ions by GL/CS is a spontaneous process of single-layer chemisorption.