Hierarchical graphite oxide decorated UiO-66 for ultrahigh adsorption of dye with synergistic effect of ultrasonication: Experimental and density functional theory study

Abstract

Indiscriminate disposal of azodyes demands the development of potential strategies for water treatment. Composites with tuned structural and functional properties, synthesized by amalgamation of 2D carbon materials with MOFs, emerges as a new generation adsorbents.Accordingly, our study focused on the synthesis of graphite oxide decorated UiO-66 MOF and its performance evaluation in ultrasonication assisted adsorptive removal of toxic Congo red dye from aqueous solution. The incorporation of GO tunes the microporous MOF to a hierarchical mesoporous/microporous structure. Theoretical analysis using density functional theory (DFT) was performed to predict the adsorption behaviour.The key finding which makes our study outstanding is the ultrahigh adsorption capacity (Qm − 1250 mg/g) of the synthesized composite, which is much higher than pure UiO-66, GO, and other reported adsorbents. The synergistic effect of the increased mesopore volume and availability of functional groups upon GO incorporation in the MOF improves the adsorption capacity. Adsorption occurs due to long-range intermolecular covalent and noncovalent interactions. The superior dye removal efficiency of the synthesized adsorbent along with good regeneration characteristics makes it a promising material for contaminants removal from aqueous solutions.