In Situ Growth of MOF from Wood Aerogel toward Bromide Ion Adsorption in Simulated Saline Water

Utilizing metal-organic framework (MOF) materials for the extraction of bromide ions (Br^-) from aqueous solutions, as an alternative to chlorine gas oxidation technology, holds promising potential for future applications. However, the limitations of powdered MOFs, such as low utilization efficiency, ease of aggregation in water, and challenging recovery processes, have hindered their practical application. Shaping MOF materials into application-oriented forms represents an effective but challenging approach to address these drawbacks. In this work, a novel Ag-UiO-66-(OH)₂@delignified wood cellulose aerogel (CA) adsorbent is synthesized using an oil bath impregnation method, involving the deposition of UiO-66-(OH)₂ nanoparticles onto CA and the uniform dispersion of Ag⁰ nanoparticles across its surface. CA, characterized by the intertwined cellulose nanofiber structure and a highly hydrophilic surface, serves as an ideal substrate for the uniform growth of UiO-66-(OH)₂ nanoparticles, which, in turn, spontaneously reduce Ag⁺ to form distributed Ag⁰ nanoparticles due to the abundant hydroxyl groups provided. Leveraging the well-defined biological structure of CA, which offers excellent mass transfer channels, and the highly dispersed Ag adsorption sites, Ag-UiO-(OH)₂/CA exhibits remarkable adsorption capacity (642 mg/g_Ag) under optimized conditions. Furthermore, an integrated device is constructed by interconnecting Ag-UiO-(OH)₂/CA adsorbents in series, affirming its potential application in the continuous recovery of Br^-. This study not only presents an efficient Ag-UiO-(OH)₂/CA adsorbent for Br^- recovery but also sheds light on the extraction of other valuable elements from various liquid ores.