Preparation of gelatin-carboxymethyl chitosan-ZIF-8 composite aerogel for adsorption of Pb(II)

With the continuous development of the economy, heavy metal pollution has posed serious environmental risks to ecosystems. Consequently, developing efficient and environmentally friendly new adsorption materials for heavy metal has become a current research focus. In this work, a gelatin-carboxymethyl chitosan-ZIF-8 composite aerogel (GCZ-4) with a three-dimensional porous structure was prepared by incorporating ZIF-8 through a simple doping method using gelatin (Gel) and carboxymethyl chitosan (CMCS) as carriers. The morphology and structure of the GCZ-4 were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Furthermore, a series of adsorption experiments were carried out to optimize the various parameters affecting Pb²⁺ adsorption behaviors. The results demonstrate that the composite aerogel exhibits excellent adsorption capacity for Pb²⁺. According to the Langmuir adsorption isothermal model, the maximum theoretical adsorption capacity of the composite aerogel for Pb²⁺ is 367.42 mg·g⁻¹. The whole adsorption process was a spontaneous exothermic process and followed the pseudo-second-order kinetic model, indicating chemisorption behavior. Moreover, even after five cycles of adsorption-desorption tests, the composite aerogel maintains high performance in removing Pb²⁺. Overall, the GCZ-4 composite aerogel is an eco-friendly, cost-efficient, and recyclable adsorbent that effectively removes Pb²⁺ from water.