Preparation of ZIF-67@Agarose Composite for Efficient Removal of Malachite Green From Wastewater

A composite aerogel of zeolitic imidazolate framework-67 (ZIF-67) and agarose (AG), denoted as ZIF-67@AG, was successfully prepared for efficient removal of malachite green (MG). Comprehensive characterization confirmed the successful formation of the composite: X-ray diffraction (XRD) patterns retained the characteristic peaks of ZIF-67, scanning electron microscopy (SEM) revealed uniform dispersion of ZIF-67 within a porous AG network, Fourier transform infrared spectroscopy (FT-IR) confirmed the characteristic functional groups of both components, and x-ray photoelectron spectroscopy (XPS) verified the presence of constituent elements. Batch adsorption experiments were conducted to investigate the effects of contact time, adsorbent dosage, solution pH, coexisting ions, and temperature on MG removal. The adsorption equilibrium data were well fitted by the Langmuir isotherm model, with a calculated maximum adsorption capacity of 1112 mg·g −1 . Kinetic analysis revealed that the pseudo-second-order model provided the best fit, suggesting a chemisorption-dominated process. Thermodynamic studies confirmed that the adsorption was spontaneous and endothermic. Furthermore, the ZIF-67@AG composite showed good reusability, maintaining a removal efficiency above 79% after six adsorption–desorption cycles. These results demonstrate that ZIF-67@AG is a promising adsorbent for the efficient removal of MG from wastewater. Graphical ZIF-67@AG aerogel was fabricated via a physical blending strategy for MG removal. ZIF-67@AG exhibited a maximum adsorption capacity of 1112 mg·g −1 . Moreover, it retained 79.69% removal efficiency after six methanol-regeneration cycles, demonstrating excellent recyclability for sustainable wastewater treatment.