Biomass@MOF nanohybrid materials for competitive drug adsorption: analysis by conventional macroscopic models and statistical physical models

Abstract

This study discloses the design of nanohybrid Biomass@MOF resulting from the functionalization of a hydrochar (HC) through hydrothermal treatment (HT) of corn cob residues and MIL-53(Al). The nanohybrid, composed of 71 wt% Biomass and 29 wt% MOF, demonstrates stability and effectiveness after leaching and stability tests. Physicochemical characterization (SEM, BET, TGA, FTIR, XRD, XRF, and XPS) of the resulting hybrid confirms the development of a new nanostructure formed via in situ growth of MOF crystals by hybridizing reticular oxygen species present on the HC surface. HC@MIL-53(Al) served as an adsorbent for pharmaceutical compounds ketorolac (KTC) and naproxen (NPX) in a two-component and competing system. Under extreme conditions, HC@MIL-53(Al) proves to be a high-performing adsorbent, removing 100% of KTC and NPX in a mixture when their concentration is up to 150 ppm. Conventional isotherm models for bicomponent systems along with physical-statistical microscopic models revealed that the complex structure of the new composite utilizes functional groups of HC (–OH) and MIL-53(Al) (CC) for physisorption of both contaminants, leading to the formation of adsorbate–adsorbate multilayers. These characteristics are further validated by a desorption study, demonstrating the ability of recovered HC@MIL-53(Al) to adsorb both contaminants with approximately 90% of their initial capacity after 5 cycles.