Chemical Engineering Research & Design, Vol.111, 127-137, 2016
Adsorptive removal of acetic acid from water with metal-organic frameworks
Six water-tolerable metal-organic frameworks (MIL-101(Cr), MIL-100(Fe), MIL-100(Cr), MIL-53(Cr), MIL-96(Al), and UiO-66) were employed for the adsorptive removal of acetic acid from water. UiO-66 exhibited more potential as an acetic acid adsorbent than other five MOFs. UiO-66 was further investigated in the view of adsorption kinetics, isotherm, thermodynamics, and regeneration of the adsorbent. The analysis of film diffusion and intraparticle diffusion model suggested that larger acetic acid concentrations would cause higher effects of boundary layer, and the adsorption process was multiple steps. The kinetic results show that adsorption of acetic acid on UiO-66 fitted to pseudo-second-order model and was controlled by chemical adsorption. The adsorption isotherm of acetic acid on UiO-66 followed Freundlich isotherm, which indicated the presence of heterogeneous surface on UiO-66. The thermodynamic parameters (Delta G, Delta H and Delta S) were also calculated, confirming that the adsorption of acetic acid on UiO-66 was spontaneously exothermic and decrease of disorder. The regeneration of UiO-66 was also demonstrated by washing with deionized water and ethanol. The adsorption capacity and XRD of UiO-66 did not change significantly even after three cycles. Therefore, UiO-66 can be a promising adsorbent for adsorptive removal of acetic acid from wastewater. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.