Preparation of carboxymethyl cellulose/graphene oxide/ZIF-8 aerogels for efficient methylene blue adsorption

Despite the promising potential of zeolitic imidazole framework-8 (ZIF-8) for dye adsorption, addressing challenges such as aggregation and recycling difficulties remains essential. Herein,a novel three dimensional (3D) carboxymethyl cellulose (CMC), graphene oxide (GO) and ZIF-8 hybrid aerogel (CGZ-3) was prepared via blending ZIF-8 into the CMC-GO matrix. The structure and composition of CGZ-3 were characterized by SEM, FT-IR, TG and XPS. Adsorption experiments were conducted to optimize various parameters affecting the behavior of methylene blue (MB) adsorption. The composite aerogel exhibited an obvious lamellar network structure, with a surface rich in oxygen-containing functional groups such as -OH and -COOH. CGZ-3 demonstrated a rapid adsorption rate for MB, achieving a removal efficiency of 96% within 15 minutes. The entire adsorption process was spontaneous and endothermic, consistent with the pseudo-first-order kinetic model and Langmuir adsorption isotherm model. The maximum theoretical adsorption capacity was 427.35 mg/g at 298 K. Selective adsorptions tests demonstrated high selectivity of the composite aerogel for MB, and dynamic adsorption further confirmed the exceptional adsorption capacity of CGZ-3. After five cycles of adsorption-desorption, the MB removal rate remained above 95%, with an adsorption capacity exceeding 240 mg/g, highlighting the stability and reusability of CGZ-3. Collectively, the CGZ-3 would be a potential material for the adsorptive removal of MB in practical water treatment.