Removal of 4-chloro-2-methylphenoxyacetic acid from water by MIL-101(Cr) metal-organic framework: kinetics, isotherms and statistical models

Abstract

Effective removal of 4-chloro-2-methylphenoxyacetic acid (MCPA), an emerging agrochemical contaminant in water with carcinogenic and mutagenic health effects has been reported using hydrothermally synthesized MIL-101(Cr) metal-organic framework (MOF). The properties of the MOF were ascertained using powdered X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and surface area and porosimetry (SAP). The BET surface area and pore volume of the MOF were 1439 m 2 g −1 and 0.77 cm 3 g −1 , respectively. Artificial neural network (ANN) model was significantly employed for the accurate prediction of the experimental adsorption capacity ( q e ) values with minimal error. A rapid removal of the pollutant (99%) was recorded within short time (approx. 25 min), and the reusability of the MOF (20 mg) was achieved up to six cycles with over 90% removal efficiency. The kinetics, isotherm and thermodynamics of the process were described by the pseudo-second-order, Freundlich and endothermic adsorption, respectively. The adsorption process is spontaneous based on the negative Gibbs free energy values. The significant correlation between the experimental findings and simulation results suggests the great potential of MIL-101(Cr) for the remediation of MCPA from water matrices.

Evaluation of Terbutaline Adsorption from Aqueous Medium by Mechanically Generated [Cu (INA)2]-MOF Metal-Organic Framework and its Modified Magnetic Composite ([Cu (INA)2]-MOF@Fe3O4)

“…To guarantee the MOF's efficiency under the equilibrium condition, the adsorption was prolonged till 120 minutes, a very good removal efficiencies of 92 and 99 % were recorded and no any further observable progress were observed after reaching the 40 minutes contact time. This result was consistent with the results of other adsorption investigations [40].…”

“…Due to their versatility, they are of great interest in both scientific and technological fields, such as liquid adsorption [40], catalysis [41], sensing [42], electrochemistry and conversions [43] as well as in biological applications such as the drug deliveries and contrasting agents [44]. A re-evaluation of the literature on the removal of β-agonists in environmental waters indicated that few research were conducted using the newly discovered materials (MOFs).…”

“…About 2 mL aliquot of the sample solution was collected at 10 minutes intervals and using filter 0.45 m nylon syringe membrane The absorbance of terbutaline in the filtrate solution was measured at λmax 283 nm by UV-Vis spectrophotometer (Shimadzu UV-1800) using a quartz cuvette. The impacts of pH were explored by varying the pH of the solution from 3, 5, 7, 9, 11, and 13 with 0.1 NaOH and M HCl before reaching the final volume of 40 ml, whilst the effects of temperature were investigated by varying the temperature from 25,30,35,40,45, and 50 °C. The adsorbent dose was also varied between 1, 2, 3, 4, 5, and 6 mg g -1 .…”

“…The kinetics model tells us how fast a solute move from an aqueous environment to a solid-phase interface at a certain dose of adsorbent, temperature, flow rate, and pH at a specific time rate. Thus, in this study, the data for terbutaline adsorption onto both the [Cu (INA)2]-MOF and [Cu (INA)2]-MOF@Fe3O4 were subjected to three major models, namely, pseudo-first-order, pseudo-second-order, and intra-particle diffusion, represented by equations ( 13), (14), and (15), respectively [40] [60].…”

Advances in Metal-Organic Frameworks MIL-101(Cr)

“…Isiyaka et al [ 121 ] introduced MIL-101(Cr) as an adsorbent for the effective removal of 4-chloro-2-methylphenoxyacetic acid (MCPA) from an aqueous solution. The rapid removal of MCPA by MIL-101(Cr) was recorded within 25 min, and the maximum adsorption capacity of MIL-101(Cr) for MCPA was 233.576 mg g −1 ; the removal rates could be over 90%.…”