Insight into the adsorption, antimicrobial, and cytotoxic activities of the green CuO decorated microcrystalline cellulose supported geopolymer nanocomposite for caffeine residuals removal.

A novel bio-composite (CuO-EXGP/MCC) was engineered by integrating microcrystalline cellulose (MCC) with exfoliated geopolymer (EXGP) and functionalizing the structure with environmentally synthesized CuO nanoparticles. This hybrid system exhibited markedly improved adsorption capabilities for eliminating CAF residues from aqueous media. The contribution of green CuO-decorated MCC to the overall performance of the EXGP matrix was evident through the adsorption data. At saturation, CuO-EXGP/MCC demonstrated an impressive adsorption capacity of 138.5 mg/g significantly outperforming EXGP (88.2 mg/g) and unmodified fly as geopolymer (52.1 mg/g). These results highlight the substantial role of the hybridization process in enhancing the surface reactivity and adsorption efficiency of the composite. Thermodynamic evaluation confirmed that the removal of CAF was driven by spontaneous and exothermic physical interactions. Due to its efficient regeneration, non-toxic nature, and reliable performance, CuO-EXGP/MCC emerges as a promising candidate for CAF removal from aqueous solution. Moreover, GP, EXGP, and CuO-EXGP/MCC all exhibited noteworthy antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Aspergillus niger, while no observable toxicity toward Artemia salina.