Tran TN, Do QC, Kim D, Kim J, Kang S. Urchin-like structured magnetic hydroxyapatite for the selective separation of cerium ions from aqueous solutions.
JOURNAL OF HAZARDOUS MATERIALS 2022;
430:128488. [PMID:
35183829 DOI:
10.1016/j.jhazmat.2022.128488]
[Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 01/29/2022] [Accepted: 02/12/2022] [Indexed: 06/14/2023]
Abstract
In this study, bio-inspired urchin-like structured hydroxyapatite (UHdA) and its magnetic composite (UHdA@Fe3O4) were developed for efficient and easy separation of cerium ions (Ce3+) from aquatic waste streams. UHdA and UHdA@Fe3O4 exhibited superior Ce3+ adsorption capacities of 248.39 and 230.01 mg/g-UHdA respectively, compared to a commercial HdA (141.71 mg/g-HdA) due to their hierarchical mesoporous structure and large specific surface area. The adsorption of Ce3+ to UHdA and UHdA@Fe3O4 were heterogeneous, pseudo-second-order-kinetic, and the rate-limiting step was external mass transfer and intra-particle diffusion. Moreover, thermodynamic studies revealed that the adsorption process was spontaneous and endothermic nature. The high selectivity towards Ce3+ in multi-ionic systems is attributed to the strong affinity between strong Lewis acid (Ce3+) and base (PO43- and OH-) interactions. XRD, FTIR, and XPS analysis demonstrated that the adsorption was mainly attributable to the ion exchange of Ce3+ with Ca2+ and to surface complexation. The desorption of Ce3+ was efficiently accomplished using 0.1 M HNO3. The results suggest that UHdA and UHdA@Fe3O4 could be promising choices for the adsorption and recovery of rare earth elements.
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