Cell-wall based aerogels for Ce (III) adsorption from leaching tailings: Properties and mechanistic research

Abstract

Efficient separation of rare earth elements (REEs) from leaching tailings is necessary for environmental protection and full utilization of resources. Cell walls are rich in various active groups that can efficiently adsorb REEs. In this work, a series of composite aerogels based on pectin and cellulose (the key active components in cell walls) were fabricated for effective adsorption of Ce (III) from leaching tailings. Physical and chemical properties of composite aerogels were characterized by Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), contact angle measuring, and a zeta potentiometer. Adsorption capacity was measured under different conditions. Adsorption corresponded to the Langmuir model and the maximum adsorption capacity of Ce (III) was 337.36 mg/g. Kinetic fitting showed that the adsorption process corresponds to the second-order kinetic model. Composite aerogels have excellent regeneration performance. The adsorption process occurred by electrostatic interaction, ion exchange with –COO−, and chelation with C-NH2. Adsorption in a sample of leaching tailings showed that the adsorption efficiency of composite aerogels for Ce (III) and Eu (III) reached 68% and 81%, respectively, demonstrating good practicability.