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Mechanism of Phosphate Desorption from Activated Red Mud Particle Adsorbents
Version 1
: Received: 29 January 2024 / Approved: 30 January 2024 / Online: 31 January 2024 (01:56:31 CET)
A peer-reviewed article of this Preprint also exists.
Yang, Z.; Li, L.; Wang, Y. Mechanism of Phosphate Desorption from Activated Red Mud Particle Adsorbents. Molecules 2024, 29, 974. Yang, Z.; Li, L.; Wang, Y. Mechanism of Phosphate Desorption from Activated Red Mud Particle Adsorbents. Molecules 2024, 29, 974.
Abstract
Herein, activated red mud particles are used as an adsorbent for adsorbing phosphorus. Different concentrations of HCl and deionized water are used for desorption tests, and the optimal desorption mechanism is investigated. The Langmuir isothermal model and pseudo-second-order kinetic linear model produce consistent results: the desorption is dominated by the surface desorption of the monomolecular layer, and chemical desorption limits the rate of surface desorption. The desorption thermodynamics indicates that the desorption of phosphorus by the desorbent is spontaneous and high temperature promotes desorption. The particle diffusion model demonstrates that the removal of phosphorus in the form of precipitation from the surface of an activated hematite particle adsorbent occurs primarily via a chemical reaction, and an analysis of the microscopic morphology indicates that the desorption process is primarily accompanied by the dissolution of the metal element Ca, followed by Al and Fe. The desorbent reacts with the active elements in red mud, and the vibration of the [SiO4]2− group calcite or aragonite group of calcium–iron garnet in the functional group disappears. The intensity of the wave peaks of the PO43− groups decreases considerably. Thus, desorption primarily involves the chemical desorption of the monomolecular layer.
Keywords
red mud; granular adsorbent; desorption mechanism; regeneration
Subject
Engineering, Mining and Mineral Processing
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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