Dialdehyde Chitosan/Semicarbazide Synthesis for Lanthanum, Cerium, and Neodymium Ions Recovery from Phosphate Leachate

ABSTRACT: Rare earth elements are among the world’s most
crucial strategic minerals. Cell phones, lamp lights, televisions, wind
turbines, and other contemporary electronics rely heavily on rare
earth elements. As a result, this work aimed to prepare eco-friendly
dialdehyde chitosan with semicarbazide (SC/DiACs), a promising
method for recovering lanthanum, cerium, and neodymium from
phosphate leach solution. Different analytical techniques were
utilized to determine the physicochemical properties of SC/DiACs
before and after adsorption. Sorption was conducted at pH 5 for 60
min using 50 mg SC/DiACs and 200 mg/L La, Ce, and Nd ions.
The sorption capacities were 193.52 mg/g for La, 186.77 mg/g for
Ce, and 171.37 mg/g for Nd. The studied ions’ sorption onto the
SC/DiACs sorbent was well-fitted by the pseudo-first-order (PFO) and the isotherm produced by Langmuir. Besides, it was
discovered that the sorption thermodynamic characteristics were both spontaneous and exothermic. La, Ce, and Nd ions were
successfully desorbed from the SC/DiACs by imperiling it to 0.7 M/L HNO3 and 35 min at 25 °C with a 1:40 solid/liquid (S/L)
ratio. Also, the SC/DiACs sorbent was rejuvenated after seven cycles of sorption−desorption. SC/DiACs sorbent was exploited to
recover RE ions from the phosphate leach solution. Ion purity levels of 90.18% were achieved by calcining the precipitate to RE
oxides. Finally, the SC/DiACs sorbent was found to have excellent sorption characteristics for RE ions in their solution, as evaluated
by the REEs recovery behaviors.