In situ growth of bimetallic Co/Zn-ZIF within wood scaffold for enhanced adsorption capacity and improved flame retardancy

Metal–organic frameworks (MOFs)/wood are attractive hybrid materials that offer a range of multifunctional properties by integrating MOFs into wood substrates. Although a good foundation has been laid in studies, it is clear that studies are limited to the conjugation of wood with monometallic MOFs. Research on the utility of novel hybrid materials designed incorporating bimetallic MOFs into wood has not yet been encountered. Herein, a novel bimetallic cobalt/zinc-based zeolite imidazolate frameworks (Co/Zn-ZIF)@wood hybrid material was successfully fabricated through in situ growth of Co-ZIF-67 and Zn-ZIF-8 within balsa wood channel arrays. SEM images indicated that Co/Zn-ZIF exhibited smaller particle sizes compared with Co and Zn monometallic MOFs. The resulting composite displays high removal efficiency up to 97.2% for methylene blue and the adsorption capacity can reach 223.6 mg·g −1 at 298 K. Moreover, the incorporation of Co/Zn-ZIF has better effect on thermal stability at the early stage and char layer formatting of wood substrate than monometallic MOFs. Compared with the monometallic MOF additives, the peak of heat release rate of the Co/Zn-ZIF@wood hybrid materials exhibited a drastic decline by 67.5% from 94.5 to 30.7 W·g −1 and the total heat release from 7.7 to 3.5 kJ·g −1 . In addition, the introduction of Co/Zn-ZIF increases the limiting oxygen index (LOI) values of the prepared composites, and the treated wood had a strong self-extinguishing ability, which manifested that Co/Zn-ZIF@wood had excellent flame retardancy. This work offers a new avenue for designing and constructing functionalized MOFs@wood composites that may boost their environmental- and green building-related applications.