Effect of Synergistic Interplay between Surface Charge, Crystalline Defects, and Pore Volume of MIL-100(Fe) on Adsorption of Aqueous Organic Dyes

Abstract

We herein report that the morphology, size, and surface charge status of MIL-100(Fe) micro/nanoparticles can be tailored by adding a coordination modulator (HF or tetramethylammonium hydroxide) to the reaction system. Interestingly, the adsorption capacities of low-crystallinity MIL-100(Fe) and MIL-100(Fe)-TMA toward Congo red (CR) and acid chrome blue K (AC) were found to be significantly larger than that of the high-crystallinity MIL-100(Fe)-HF adsorbent, whereas there was little difference in the adsorption capacities of the three MIL-100(Fe) toward methyl orange (MO) and methylene blue (MB). The adsorption uptake of MIL-100-(Fe)-TMA toward the anionic dyes (CR, AC, and MO) was found to be highest, whereas the adsorption uptake of MIL-100(Fe) toward the cationic dye (MB) was the highest owing to different adsorption mechanisms. This adsorption behavior could be rationalized based on the morphological characteristics and crystal structure defects, zeta potential, and pore volume of MIL-100(Fe) and the adsorption characteristics and molecular structure of the dye. It was revealed that the adsorption performance of MIL-100(Fe) micro/nanoparticles is governed by the synergistic interplay between electrostatic, hydrophobic, and π−π stacking interactions, pore volume, crystal structure defects, and steric hindrance of the adsorbent.

Exploring the Effect of Iron Metal-Organic Framework Particles in Polylactic Acid Membranes for the Azeotropic Separation of Organic/Organic Mixtures by Pervaporation

“…The literature previously documented the possible presence of an amorphous phase for the MIL-100 structures obtained in water without HF [ 31 ]. Such is known as HF, which acts as coordinator modulator [ 49 ] improves the crystallinity of product [ 50 ]. However, due to the toxicity, the replacement of HF in the synthesis is auspicial, although it means to obtain a product with lower crystallinity [ 33 ].…”

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

“…[ 35–37 ] Third, the μ‐OH (Zr‐OH‐Zr) of the SBU may interact with the dyes via H‐bond interaction, and π–π stacking is possible between the benzene rings of the ligand (BTC) and the dyes. [ 20,38,39 ] However, due to similar structural units (π‐conjugated units) and chemical groups (free carboxyl), the interactions above may exist between MOF‐808 and both of FS and RhB. That is, these host–guest interactions may not be the key factor for the separation.…”

“…Metal–organic framework (MOF), assembled by inorganic clusters and organic ligands, attracted large attention in many applications, for example, catalysis, [ 8–10 ] energy engineering, [ 11,12 ] sensing, [ 13 ] and adsorptive separation. [ 14,15 ] In particular, thanks to regular pore structures, large specific surface areas, and tunable adsorption sites, MOFs have been applied in liquid‐phase adsorption and separation for dyes, [ 16–20 ] metal ions, [ 21,22 ] biological molecules, [ 23,24 ] and antibiotics. [ 25,26 ] Up to date, the potential of MOFs for adsorption andseparation of various dyes has been investigated, for example, methylene blue (MB), methyl orange (MO), and Congo red (CR).…”

Influence of carbohydrate polymer shaping on organic dye adsorption by a metal–organic framework in water

“…Generally, hydrogen uoride (HF) is used as a crystallizing agent to obtain highly crystalline MIL. [19][20][21][22] However, from the viewpoint of green chemistry, toxic HF was not used in the preparation of MIL employed in this study. 17 The obtained MIL is stable in water, which was conrmed by the result of colorimetric measurements that show no leakage of iron ions from MIL into water.…”

“…1), 17,18 has been utilized as a potential adsorbent for removing organic and inorganic pollutants in aqueous solution. 12,[19][20][21][22][23] Fe is a very abundant less toxic metal, and 1,3,5-benzenetricarboxylic acid is commercially available and has been used for the synthesis of a variety of MOFs. 17,18,24,25 Moreover, MIL is highly stable in water because it contains a strong Fe 3+ trivalent cation-COO À monoanion coordination bond.…”