Sustainable paper-based composite with beta-cyclodextrin and metallic nanoparticles for efficient nitroaromatic...

Organic pollutants such as nitroaromatic compounds (NACs) have extensively contaminated aquatic environments. This research proposes a composite based on paper, beta-cyclodextrin (βCD), and metallic nanoparticles (MNPs) for the effective removal of NACs from water. The synthesis involved a green and sustainable approach, utilising sonication to fabricate paper-AuNPs/βCD, paper-AgNPs/βCD, and paper-CuNPs/βCD (ternary systems). Physicochemical and mechanical characterization confirmed the successful formation of the paper-MNPs/βCD composites. The results demonstrated that the ternary systems exhibited superior adsorption capacity for three NACs: 4-nitrobenzoic acid, 4-nitroaniline, and 4-nitrothiophenol, compared to the individual components. The interaction between NACs and the ternary system was evaluated using kinetic and adsorption isotherm models. The interaction process followed pseudo-second-order kinetics and was best described by the Freundlich isotherm, confirming the adsorption behavior. All paper-MNPs/βCD composites subjected to remediation experiments in wastewater samples achieved up to 90 % removal for NACs after 20 min, demonstrating their high efficiency. Additionally, the recyclability of the ternary systems was evaluated through adsorption/desorption cycles. The NAC removal percentages remained above 50 % over three consecutive reuses. Finally, when tested in real water samples from the Mapocho River, all composites achieved up to 80 % NAC removal within 20 min, demonstrating consistent performance even in complex environmental matrices. These findings highlight the efficiency, reusability, and potential application of paper-MNPs/βCD composites for the removal of NACs from aqueous environments.