Thermodynamic Investigation and Study of Kinetics and Mass Transfer Mechanisms of Oily Wastewater Adsorption on UIO-66–MnFe2O4 as a Metal–Organic Framework (MOF)

Abstract

Hitherto, a considerable amount of research has been carried out to investigate the equilibrium condition of adsorption process; nevertheless, there is no comprehensive study to evaluate the surface adsorption properties of MOFs. Therefore, the adsorption mechanism and equilibrium capacity of MOFs have not been fully understood. Furthermore, the mass transfer mechanism is still unknown and so it is not possible to predict the adsorption process using MOFs. In this work, a new metal–organic framework (MOF) named UIO-66–MnFe2O4 was synthesized as an adsorbent for oily wastewater treatment. In this way the effects of temperature, amount of adsorbent, adsorption time, pH, and pollutant initial concentration were studied in the treatment of oily wastewater using the UIO-66-MnFe2O4 MOF through the adsorption process. Furthermore, to examine the process of surface adsorption, different adsorption kinetic models (pseudo-first-order, pseudo-second-order, and Elovich) have been performed for the removal of oily pollutants on MOF adsorbents and the surface adsorption mechanism has been discussed carefully. Moreover, to investigate the mass transfer mechanism of oily pollutants in the surface adsorption process, different mass transfer models (Weber and Morris, liquid film diffusion, and Bangham and Burt) have been investigated on porous adsorbents, and finally the mass transfer mechanism of the adsorption process has been proposed.