Abstract For the first time, pure monoclinic ZrO₂ nanocrystals were successfully synthesized via a simple, one-step, and surfactant-free thermal decomposition method using a single precursor compound. In this synthesis, no chemical additives were used; only the metal–organic precursor was employed. This one-step synthesis is notable for its environmental friendliness, low cost, and scalability. Pure-monoclinic structured ZrO 2 has been synthesized in a one step and for the first time applied as an adsorbent to remove molybdenum ions from 3.0 M HNO 3 solution. The nano-oxide was characterized by XRD, SEM, TEM, FTIR, and TGA/DTA to evaluate its structure, morphology, functional groups, and thermal stability. Synthesized ZrO 2 nanocrystals have a pure-monoclinic phase with an average particle size ranging from 14 to 28 nm. To evaluate its performance in radioactive waste treatment, the sorption capacity of pure monoclinic nano-zirconium oxide (Pm-ZrO₂) was investigated for the removal of Mo(VI) from simulated high-level liquid radioactive waste (3.0 M HNO 3 ). The equilibrium sorption behavior of Mo(VI) on Pm-ZrO₂ was evaluated using Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models, whereas the kinetic analysis was conducted based on pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. Kinetic analysis indicated that the sorption process is best described by the pseudo-second-order model, implying that chemisorption is likely the rate-controlling mechanism. The equilibrium sorption isotherm of Mo(VI) onto Pm-ZrO₂ was best represented by the Langmuir and Dubinin–Radushkevich models, suggesting monolayer adsorption occurring on a uniform surface. The maximum equilibrium sorption capacity was found to be 66.70 mg/g, confirming the promising potential of Pm-ZrO₂ as an efficient adsorbent for Mo(VI) removal from acidic radioactive media. Graphical Abstract
Hamed et al. (Tue,) studied this question.