Cadmium‐based metal–organic framework for removal of dye from aqueous solution

Abstract

Metal–organic framework ([Cd2(oba)2(4‐bpdb)2] n·3.5(DMF)) (TMU‐8) was successfully synthesized via mechanosynthesis by using nonlinear dicarboxylate and linear N‐donor. The TMU‐8 exhibited accessible cages and tunnels, specific adsorption making it excellent adsorbent for dye removal. The obtained TMU‐8 exhibited accessible cages and tunnels, specific adsorption making them excellent adsorbent for dye removal. The adsorption isotherms, kinetics, thermodynamics, and spectroscopic analyses of the removal of the reactive black 5 onto TMU‐8 were studied. Several variables affecting the removal of the reactive black 5, such as sample pH, amount of sorbent, contact time, and salt concentration, were investigated and optimized. The thermodynamic parameters and kinetics characteristics were also analyzed. The thermodynamic parameters and kinetics characteristics were analyzed. The experimental isotherms data were fitted into Freundlich, Temkin, and Langmuir isotherm equations, and the results indicated that the Langmuir isotherm described the data appropriable than others for reactive black 5 adsorptions. The qmax (mg g−1) was calculated from the Langmuir as 79.36 mg g−1. The fitness of equilibrium data to kinetic models such as, pseudo‐first‐order and pseudo‐second‐order were studied. The adsorption followed pseudo‐second‐order kinetics. Thermodynamic parameters like the enthalpy, entropy, and Gibbs free energy were determined by the Gibbs free energy function, confirming that the adsorption process was spontaneous, exothermic, and feasible.

Recent Advances in MOF-Based Adsorbents for Dye Removal from the Aquatic Environment

“…Hazrati et al [93] synthesized TMU-8 with the solvothermal method and applied it to remove reactive black 5 (RB5) dye from the aquatic environment. The maximum capacity obtained was 79.36 mg/g for the RB5 adsorption.…”

“…Over time, active sites of adsorbent are occupied by dye molecules and the adsorbent can no longer adsorb more dyes, whereby the adsorption process stops [192,193]. Most MOFs need a very short time to reach the equilibrium point of adsorption [86,89,92,93,95,184]. Fast adsorption may be due to various interactions between MOF and contaminant molecules.…”

Dye contaminated wastewater treatment through metal–organic framework (MOF) based materials

“…161 Safari et al have shown that the adsorption of dye on a MOF in wastewater may be due to p-p stacking between the ligand of the MOF and the arene part of the dye molecule. 161 p-p Stacking is also observed between the aromatic part of imidazole rings in ZIF-8 (MOF) and the arene part of the malachite green, resulting in higher adsorption efficiency of MG with ZIF-8. 111 There are few reports on the hydrogen bonding mechanisms between MOFs and dyes.…”

TMU‐24 (Zn‐based MOF) as an advance and recyclable adsorbent for the efficient removal of eosin B: Characterization, equilibrium, and thermodynamic studies

“…29 MOFs have attractive structural properties such as low framework densities, uniformly structured nanoscale cavities, accessible cages, high surface area, tunnels and modifiable pores, good chemical resistance and specific adsorption affinities make MOFs attractive materials for sorbents of pollutants. 30,31 Up to date, there are large numbers of reported MOFs and some of them have been studied for liquid adsorption. [32][33][34] However, most MOF materials suffer from insufficient aqueous stability, mainly over a broad range of pH values.…”