Synergistic effects of graphene oxide loading and particle size in ice- templated carboxymethyl cellulose–based aerogels on dye removal

Sustainable carboxymethyl cellulose/graphene oxide (GO) aerogels were fabricated via epichlorohydrin cross-linking and ice-templating for effective methylene blue (MB) removal from aqueous solutions. The synergistic effects of GO loading (1, 3, and 5 wt%) and particle size (500, 10, and 1 nm) on the structural, mechanical, and adsorption properties of aerogels were systematically explored. The optimal dye adsorption capacity (555.6 mg/g) was obtained at 3 wt% GO loading, owing to enhanced π–π stacking, hydrogen bonding, and electrostatic interactions between GO and MB. Conversely, excessive GO loading caused nanosheet aggregation, decreasing adsorption efficiency. Reducing GO particle size to 1 nm notably improved the compressive strength (546 kPa) of aerogels because of uniform dispersion but deteriorated adsorption performance by disrupting interlayer interactions (π–π stacking). The 10 nm–GO composite achieved the optimal balance, demonstrating high adsorption capacity (416.7 mg/g) and adsorbate affinity ( K _L = 0.387 L/mg). Spectroscopic and morphological analyses confirmed successful cross-linking, improved pore structure, and interfacial compatibility. Adsorption kinetics followed the pseudo-second-order model, whereas the isotherm data fitted well to the Langmuir model, indicating monolayer chemisorption. The aerogel retained >93% of its initial efficiency after five reuse cycles, demonstrating excellent reusability and potential for sustainable dye-laden wastewater treatment.