Interfacial mechanisms of 6PPD-quinone adsorption on metal-organic framework functionalized nanocellulose aerogels

Understanding the interfacial adsorption pathways of tire‑derived contaminants on hybrid porous materials is critical for advancing colloid and interface science. Here, we design a hierarchically structured metal-organic framework (MOF)‑functionalized nanocellulose (MOF@NC) aerogel using dicarboxylic cellulose nanocrystal (DCN)‑mediated interfacial bridging, forming a chemically active and spatially interconnected adsorption network. The adsorption of 6PPD‑quinone was evaluated through kinetic, isotherm, and thermodynamic analyses, revealing rapid chemisorption consistent with a pseudo‑second‑order model and monolayer adsorption on energetically uniform sites following the Langmuir model, with a maximum adsorption capacity of 20.0 ± 0.5 mg g⁻¹ . The MOF@NC aerogel retained approximately 87.2 ± 2.4 % of its initial adsorption efficiency after five adsorption‑desorption cycles, demonstrating good interfacial stability and reusability. Spectroscopic analyses (FTIR, XPS, SEM‑EDS) identify multiple interfacial interactions, including amide‑bond formation, Lewis acid-base coordination with MOF Zr-oxo clusters, π–π stacking between aromatic domains, hydrogen bonding, and dispersive interactions. Complementary density functional theory (DFT) and reduced density gradient (RDG) reveal energetically favorable adsorption configurations, and pronounced electronic redistribution at the MOF-nanocellulose heterointerface. By integrating macroscopic adsorption behavior with molecular-level interfacial analysis, this work establishes a mechanism-oriented framework for interpreting adsorption at MOF-biopolymer hybrid interfaces, thereby advancing fundamental understanding of how hybrid colloidal interfaces govern the sequestration of aniline-derived contaminants beyond prior performance-focused studies.