Adsorption Properties of UiO-66/Wood Hybrid Adsorbent for Organic Dye Removal

The effective treatment of dye effluent requires efficient, economical, and eco-friendly adsorbents. However, the adsorbents commonly in use are often expensive and pose recycling challenges. Wood, owing to its abundance, low cost, and environmental compatibility, is promising as an adsorbent material. In this study, a UiO-66/wood hybrid adsorbent was synthesized by employing TEMPO oxidation on natural wood as a support after delignification, followed by the in situ generation of UiO-66. Adsorption experiments indicated that the UiO-66/wood hybrid adsorbent displayed a preference for cationic dyes, particularly crystal violet, over anionic dyes. Our study of the adsorption mechanism suggests that selective dye adsorption might result from a combination of electrostatic effects and size matching, a characteristic endowed by UiO-66, as evidenced by our molecular modeling results. Further investigation on account of independent gradient model based on Hirshfeld partition of molecular density (IGMH) method revealed that the main non-covalent interactions between UiO-66 and the dye were van der Waals interaction, π-π stacking, and hydrogen bonding. The adsorption mechanism study provides a theoretical basis for the design and preparation of adsorbent with tailored adsorption properties.