Selective adsorption and separation of dyes from aqueous solution by a zirconium‐based porous framework material

Abstract

A water‐stable zirconium‐based metal–organic framework, MOF‐808, has been applied in selective adsorption and separation of the dyes (anionic fluorescein sodium [FS] and cationic rhodamine B [RhB]). Single‐component adsorption experiments indicate the superior adsorption of FS with a maximum adsorption capacity of 480.2 mg g−1, almost four times of the capacity for RhB. Further separation study shows that separation of these dyes can be achieved at a wide pH range of 3.5–8.5 and continuous separation is feasible in a simulated chromatographic column. Besides, this material can be well regenerated through acid washing method. Pore sieving effect is considered to be the key factor for the highly efficiency separation, and the host–guest interactions including H‐bond, π–π stacking, and coordination interactions are the main driven forces for the adsorption. Thus, this work demonstrates that MOF‐808 not only is a promising material for efficient separation of FS and RhB but also provides a new perspective for developing adsorbent with the help of distinct pore and chemical properties of MOFs.

Defect-engineered metal–organic frameworks (MOF-808) towards the improved adsorptive removal of organic dyes and chromium (vi) species from water

“…[25][26][27] To the best of our knowledge, although there have been several studies on MOF-808 with deliberated introduced defects, most of them aimed for water adsorption, phosphate sequestration, and catalytic applications, 12,25,[27][28][29][30] while the employment of defective MOF-808 for the removal of contaminants in aqueous solution is still rare in the literature. 31,32 Recently, original MOF-808 turned out to be an effective adsorbent to capture organic dyes and oxometallate compounds, namely sunset yellow, quinoline yellow, and the Cr (VI) anion, with impressive performances as compared to traditional materials, such as activated carbon or mesoporous silica materials. 26 Although this finding provided a comprehensive overview regarding the impact of the MOF-808 morphology, including particle size and crystallinity on its anion trapping ability, the effect of defective sites, which could also serve as effective active centers, was not mentioned.…”

A sulfonate ligand-defected Zr-based metal–organic framework for the enhanced selective removal of anionic dyes

“…12, the adsorption capacity of the recovered MOF-808-S for the tested dyes exhibited minor decreases (0.5–3%) in the second cycle and the activity loss was more significant (5–15%) in the subsequent cycles, which was possibly attributed to the incomplete removal of the dye species from the material and the collapse of the MOF framework. 12,27 The presence of these dye molecules could be detected on the FTIR spectra of the recovered MOF-808-S (Fig. S8†).…”

“…This not only proved the higher adsorption efficiency of MOF-808-S in dye mixtures but also the stronger selectivity towards anionic species, which were in good agreement with some previous literature employing MOF-808 for selective adsorption of dye mixtures. 12,27,32…”

Air-Derived Inhibitor of Nanozymes

“…After exclusion of the possible influence of HCO 3 – on the reaction system pH, we then investigated the possible occupation of HCO 3 – on the Ce 6 clusters in Ce-MOF-808 NPs. Negatively charged dyes have been widely adsorbed by MOFs due to the interaction between functional groups such as the carboxyl groups of dyes and the metal nodes of MOFs. , Fluorescence sodium (FS) is a typical negatively charged dye containing carboxyl groups and phenol groups, which is supposed to be adsorbed on the Ce 6 clusters in Ce-MOF-808 NPs. We speculate that the addition of HCO 3 – could not only inhibit the adsorption of FS but also release the adsorbed FS on Ce 6 clusters (Figure a).…”