Defect-Rich Hierarchical Porous UiO-66(Zr) for Tunable Phosphate Removal

Abstract

The introduction of defects into hierarchical porous metal−organic frameworks (HP-MOFs) is of vital significance to boost their adsorption performance. Herein, an advanced template-assisted strategy has been developed to fine-tune the phosphate adsorption performance of HP-MOFs by dictating the type and number of defects in HP-UiO-66(Zr). To achieve this, monocarboxylic acids of varying chain lengths have been employed as template molecules to fabricate an array of defect-rich HP-UiO-66(Zr) derivatives following removal of the template. The asprepared HP-UiO-66(Zr) exhibits a higher sorption capacity and faster sorption rate compared to the pristine UiO-66(Zr). Particularly, the octanoic acid-modulated UiO-66(Zr) exhibits a high adsorption capacity of 186.6 mg P/g and an intraparticle diffusion rate of 6.19 mg/g•min 0.5 , which are 4.8 times and 1.9 times higher than those of pristine UiO-66(Zr), respectively. The results reveal that defect sites play a critical role in boosting the phosphate uptake performance, which is further confirmed by various advanced characterizations. Density functional theory (DFT) calculations reveal the important role of defects in not only providing additional sorption sites but also reducing the sorption energy between HP-UiO-66(Zr) and phosphate. In addition, the hierarchical pores in HP-UiO-66(Zr) can accelerate the phosphate diffusion toward the active sorption sites. This work presents a promising route to tailor the adsorption performance of MOF-based adsorbents via defect engineering.

Highly sensitive colorimetric detection and effective adsorption of phosphate based on MOF-808(Zr/Ce)

“…Many studies show that Zr and Ce have an affinity to phosphate, having efficiency adsorption capacity towards phosphate. 48,49 The characterization results above also suggested that phosphate can be attached to MOF-808(Zr/Ce). Therefore, the adsorption properties of MOF-808(Zr/Ce) for phosphate were also investigated.…”

The Influence of Multisensor Fusion Machine Learning on the Controllable Fabrication of MOF (UIO-66)/ZrAl Ceramic Composite Membranes

“…Different structures of UIO-66 have differ-ent functions. Therefore, controllable preparation of UIO-66 according to its different functions and properties of different spatial structures is a method to utilize UIO-66 complexes [14] effectively. UIO-66 is generally prepared by accurately weighing 0.053 g of ZrCl 4 (0.227 mmol) into 24.9 g of DMF (340 mmol) solvent and sonicated to dissolve completely.…”

Tailoring Defect Density in UiO-66 Frameworks for Enhanced Pb(II) Adsorption

“…A more recent concept, defect engineering, has gained great interest in MOFs to expose active sites hidden in the frameworks and to expand their potential applications. − A heedful removal of part of the linkers or metal nodes, commonly employed in the defect engineering, produces a great diversity in MOF features including larger accessible internal area, enhanced porosity, and increased number of catalytic and adsorption sites, which significantly improve the performances in relevant applications. , For example, defective UiO-66 dramatically increased the catalytic performances by the addition of trifluoroacetic acid, which caused the missing linker defect in the framework . UiO-66 is a prototype MOF in defect engineering and it easily tolerates a great number of defects without loss of the structural framework due to the strong metal-linker coordination and high connectivity of the framework, which makes it fascinating and unique in the MOF family .…”