Chitosan Aerogel Composited with Cu-Functionalized UiO-66-NO2 as Recyclable Adsorption of Primary Aromatic Amines in Wastewater

Primary aromatic amines (PAAs), such as 4,4′-methylenedianiline (MDA) and 4-chloroaniline (4-CA), are toxic, carcinogenic, and persistent pollutants widely detected in aquatic environments. To address this issue, UiO-66 was modified through nitro functionalization, copper doping, and defect regulation, and further integrated with chitosan (CS) to construct a composite aerogel (CS@CuUiO-66-NO2) for the removal of MDA and 4-CA from wastewater. The adsorbent demonstrated relatively fast adsorption kinetics (MDA: 6 h; 4-CA: 4 h) and high adsorption capacities (MDA: 643.74 mg·g−1; 4-CA: 491.54 mg·g−1), showing improved performance compared to pristine UiO-66 and many previously reported adsorbents under similar conditions. The enhanced adsorption performance is likely attributed to the synergistic effects of multiple interactions, including hydrogen bonding, π-π interactions, and possible coordination interactions between functional groups of the adsorbent and PAAs. Moreover, the adsorbent maintained good adsorption performance after five adsorption–desorption cycles, with only a slight decrease in efficiency (~8%), and exhibited limited interference from coexisting anions. Overall, this study presents a feasible strategy for designing porous composite adsorbents with favorable reusability for potential applications in aqueous pollutant remediation.