Zeolitic imidazolate framework/graphene oxide hybrid nanosheets functionalized chitosan/poly (2-acrylamido-2-methyl-1-propane sulfonic acid-co-sodium acrylate) for Cu (II) adsorption

The investigation centered on developing a hybrid nanosheets composed of zeolitic imidazolate framework-8 and graphene oxide (ZIF-8/GO), where ZIF-8 crystals were grown on GO layers. These were subsequently functionalized with a composite of chitosan and poly (2-acrylamido-2- methyl-1-propane sulfonic acid-co-sodium acrylate) (CS/P(AMPS-co-NaAA)). The fabricated ZIF-8/GO@CS/P(AMPS-co-NaAA) nanocomposite demonstrated its capability to remove Cu (II) ions from contaminated water. Analytical techniques such as Fourier Transform Infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) were employed to characterize the material. Optimization of the adsorption process was achieved by adjusting critical variables, including the pH of the solution, contact time, the quantity of adsorbent used, and the concentration of the metallic ion initially present. An impressive removal efficiency of 98.1% was recorded. Furthermore, an elevation in temperature appeared to increase the adsorbent’s capacity for capturing copper ions. Moreover, the equilibrium behavior of the adsorption was assessed using several isotherm models—Freundlich, Temkin, Langmuir, and Dubinin-Radushkevich, with the Freundlich isotherm providing the best correlation. Kinetic studies supported the pseudo-second-order kinetic model, and thermodynamic analyses confirmed the spontaneous and endothermic nature of the adsorption. These results underscore the high effectiveness of the synthesized adsorbent in the remediation of Cu (II) from wastewater.