Rationally Tailoring Pore and Surface Properties of Metal–Organic Frameworks for Boosting Adsorption of Dy³⁺

Abstract

The adsorption and recovery of dysprosium ions (Dy3+) from industrial wastewater are necessary but still challenging. Herein, we constructed a series of defect-containing metal–organic frameworks (MOFs) [UiO-66-(COOH)2] using sodium benzoate (BCNa) as a modulator. Upon the formation of defects, the porosity and surface charge properties of the MOFs were improved, leading to a higher utilization ratio of active groups and higher adsorption capacities for Dy3+. The synthesized UiO-66-(COOH)2-B10 with an optimal addition of BCNa exhibited a superior adsorption capacity of 150.6 mg g–1. Fast adsorption occurred at ∼5 min, and equilibrium was reached at ∼60 min. Higher pH and temperature were found to be beneficial for boosting Dy3+ adsorption, and selective adsorption over other metal ions was achieved in a multicomponent solution. Further, FTIR spectroscopy and XPS investigations indicate that free carboxyl contributes to the capture of Dy3+. Thus, this work provides a promising strategy to enhance the utilization ratio of active groups and further adsorption performance.

Adsorption and photocatalytic desorption toward Cr(vi) over defect-induced hierarchically porous UiO-66-(OH)2: a sustainable approach

“…6 Å), 15 inhibiting the maximum sorption capacity and the diffusion rate of contaminant into the frameworks. Modulating the UiO-66 framework via defect engineering could obtain larger pore sizes and more sorption sites than perfect UiO-66, 16,17 which would overcome these disadvantages to further boost the adsorption performance. For instance, our group firstly utilized seignette salt to coordinate Zr(IV) on the [Zr 6 O 4 (OH) 4 ] cluster of NH 2 -UiO-66 to achieve partial missing of Zr atoms and linkers, leading to both the exposure of rich unsaturated coordination oxygen and the formation of hierarchical pores.…”

Preparation and performance of UiO‐66‐(COOH)2‐based mixed matrix membranes for efficient separation of Sr2+ ions from aqueous solutions

“…For the three initial concentrations, within the first 60 min, the adsorption capacity of Sr 2+ ions increased rapidly with time. This could be attributed to the −COOH groups of UiO‐66‐(COOH) 2 , which provided sufficient active sites for the adsorption of Sr 2+ ions 27 . Then, with the contact time increased to 120 min, the adsorption sites on UiO‐66‐(COOH) 2 were completely occupied, resulting in the adsorption reaching equilibrium.…”

“…Considering that the reaction is carried out in an aqueous solution of metal ions, nanomaterials should be combined with MOFs with water stability. Some water‐stable MOF materials, including UiO‐66, hierarchical UiO‐66 (H‐UiO‐66), MIL‐125 and MIL‐68, can be used to adsorb and remove metal ions from aqueous solution 27 . Due to the water stability of UiO‐66 species, UiO‐66‐(COOH) 2 is suitable as an additive to be added to PES membrane substrate materials.…”

Tuning the Dual Active Sites of Functionalized UiO-66 for Selective Adsorption of Yb(III)

“…The first sharp mass degradations are observed when the temperatures are below about 260 °C for UiO-66-COOH and 160 °C for UiO-66-(COOH) 2 . These degradations can be attributed to the dissociation of coordinated benzoate and dehydroxylation of the Zr 6 O 4 (OH) 4 cluster . The second mass losses in the temperature range of 400–620 °C are mainly ascribed to the collapse of the UiO-66 framework and formation of ZrO 2 , resulting in large mass losses of 47.8 and 54.7%, respectively .…”

“…These degradations can be attributed to the dissociation of coordinated benzoate and dehydroxylation of the Zr 6 O 4 (OH) 4 cluster. 37 The second mass losses in the temperature range of 400−620 °C are mainly ascribed to the collapse of the UiO-66 framework and formation of ZrO 2 , resulting in large mass losses of 47.8 and 54.7%, respectively. 37 In terms of UiO-66-COOH-TETA and UiO-66-(COOH) 2 -ED, their thermal stabilities are obviously improved after the pristine carboxyl-UiO-66s are grafted with TETA or ED, ultimately providing a mass loss of 35.7 and 39.0%, respectively.…”