Abstract
The interaction of eosin B dye from aqueous solution with MIL-100(Fe) and functionalized MIL-100(Fe) metal–organic frameworks (MOFs) is reported in this study. MIL-100(Fe) was prepared and functionalized with thioglycolic acid (TH) and ethylenediammine (ED) separately by incorporating the thiol (–SH) and the amine (–NH2) group of the functionalizing agents into the open metal sites of the MIL-100(Fe) to obtain the acidic (TH-MIL-100) and basic (ED-MIL-100) forms of the MOF respectively. Characterization of the MOFs was done by melting point analysis, elemental analysis, spectroscopic techniques, scanning electron microscopy (SEM), and powdered X-ray diffraction (PXRD) analysis. The adsorption experiments were carried out at different conditions such as pH, adsorbent dosage, contact time, temperature, and initial concentration of the dye to estimate the optimum conditions and the maximum adsorption capacities. Adsorption capacities were observed to increase in the order of ED-MIL-100 < MIL-100 < TH-MIL-100, while the TH-MIL-100 was the most effective in the removal process due to acid–base interaction between the acidic thiol group (–SH) and the alkaline medium of eosin B dye solution. The Langmuir Isotherm was seen to fit well to adsorption data obtained for all three adsorbent materials studied, and adsorption processes followed the pseudo-second order kinetics. This study, therefore, indicates the suitability of functionalization of MIL-100(Fe) towards improving its adsorption capacity.
Highlights
Porous coordination polymers (Metal–organic frameworks (MOFs)) have been presented as emerging materials showing high degree of porosity and extensively studied due to unique characteristics which include structural flexibility and rigidity, high degree of pore volume, and their uniquely high specific surface area [1]
The amount of the eosin B dye adsorbed on the adsorbents was observed to increase as the concentration of the dye increased reaching a maximum at 25 mg/L for MIL-100 and thioglycolic acid (TH)-MIL-100, and 20 mg/L for ED-MIL-100
The synthesized metal–organic frameworks (MOFs) were used as adsorbents for the removal of eosin B dye from aqueous solution
Summary
Porous coordination polymers (Metal–organic frameworks (MOFs)) have been presented as emerging materials showing high degree of porosity and extensively studied due to unique characteristics which include structural flexibility and rigidity, high degree of pore volume, and their uniquely high specific surface area [1]. The internal surfaces of MOFs are susceptible to tuning to achieve the desired characteristics enabling their preparation for specific purposes [1, 2]. The large number of available ligands with a variety of functionalities have enabled the achievement of MOFs having a variety of functional groups. Synthesis processes using these ligands alone sometimes do not achieve the desired functionalities or MOF structure in these materials, it becomes imperative in this case to develop alternative routes such as functionalization to achieve desired MOF properties by interacting the functional groups on the ligands with post synthetic functionalizing agents to generate MOFs having the desired characteristics [14, 15]. The two mesoporous cage sets (24 and 29 Å) are reportedly accessible through the microporous windows (ca.8.6 Å and ca.4.7–5.5 Å) of the material [16, 17], and the non-toxic nature of the F e3+ ion which is inexpensive and environmentally friendly gives the MIL-100(Fe) its importance and desirability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
