In Situ-Grown Zeolitic Imidazolate Framework-8@Mg-Fe Layered Double-Hydroxide Heterostructure with Enhanced Adsorption Properties: Insights from Experimental and Computational Investigations.

The removal of organic pollutants, especially dyes, from wastewater remains a critical environmental challenge. Metal-organic frameworks (MOF) and layered double hydroxides (LDH) have individually demonstrated a strong adsorption potential for organic and inorganic contaminants in aqueous media. However, integrating their complementary properties into heterostructures offers a promising route to synthesize efficient adsorbent materials for water/wastewater treatment. In this work, a hierarchical zeolitic imidazolate framework-8@Mg-Fe layered double-hydroxide (ZIF-8@Mg-Fe-LDH) heterostructure was synthesized by in situ growth of ZIF-8 on Mg-Fe LDH, and its structure-activity relationship was investigated for the adsorption of model organic dyes, acid orange 7 (anionic) and rhodamine B (cationic). The ZIF-8@Mg-Fe-LDH heterostructure exhibited both micro- and mesopores, with a specific surface area that is larger than that of the parent LDH. First-principles density functional theory (DFT) calculations, combined with machine-learning interatomic potential (MLIP) studies, provided atomic-level insights into the adsorption mechanism. These findings provide insights into the structure-function relationship between ZIF-8@Mg-Fe LDH and organic pollutants (specifically dyes) and provide a pathway for designing new metal-organic framework@layered double-hydroxide heterostructures for the efficient remediation of aqueous pollutants.