The MOF⁺ Technique: A Significant Synergic Effect Enables High Performance Chromate Removal

Abstract

A significant synergic effect between a metal–organic framework (MOF) and Fe2SO4, the so‐called MOF+ technique, is exploited for the first time to remove toxic chromate from aqueous solutions. The results show that relative to the pristine MOF samples (no detectable chromate removal), the MOF+ method enables super performance, giving a 796 Cr mg g−1 adsorption capacity. The value is almost eight‐fold higher than the best value of established MOF adsorbents, and the highest value of all reported porous adsorbents for such use. The adsorption mechanism, unlike the anion‐exchange process that dominates chromate removal in all other MOF adsorbents, as unveiled by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), is due to the surface formation of Fe0.75Cr0.25(OH)3 nanospheres on the MOF samples.

The MOF+ Technique: A Potential Multifunctional Platform

“…Recently, we found that MOF + technique could be a good alternative to solve this problem (Figure ). Relative to the pristine MOF samples of USTA‐74 that gives no adsorption toward Cr VI , the samples with the presence of FeSO 4 affords ultrahigh Cr VI removal up to 796 Cr mg g −1 .…”

Microbial reduction of metal-organic frameworks enables synergistic chromium removal

“…For example, some metal-organic frameworks have been used for Cr(VI) adsorption, but generally show slow adsorption kinetics and limited capacities 30–32 . A more recent study found that Cr(VI) adsorption to a metal-organic framework could be dramatically improved by adding exogenous Fe(II) 33 . This result implies that, similar to the case with iron oxides, the presence of Fe(II) can enhance reductive adsorption of Cr(VI).…”

A robust Th-azole framework for highly efficient purification of C2H4 from a C2H4/C2H2/C2H6 mixture

“…And partial hydrogenation of acetylene into ethylene over catalyst 10 or solvent extraction of cracked olefins 11 are also involved with the purification of ethylene from acetylene. Adsorptive separation by porous materials is an alternative technology, especially, some metal-organic frameworks (MOFs) [12][13][14][15][16][17][18][19][20][21] with high volume, designable pore characteristics, and countless structural possibilities, can be employed into the gas separation processes, the adsorption selectivity and capacity are higher than the results of conventional adsorbents [22][23][24] such as zeolites and carbon-based, especially the adsorption and separation for C 2 H 6 /C 2 H 4 8,22,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] .…”