What question did this study set out to answer?

The aim is to synthesize pure monoclinic zirconium dioxide nanocrystals and evaluate their performance in removing molybdenum ions from acidic solutions.

March 13, 2026Open Access

Thermal Decomposition Route for Synthesis of Pure-Phase Zirconium Dioxide Nanocrystals and their Application in the Sorption of Molybdenum Ions in Nitric Acid Solution

Key Points

The aim is to synthesize pure monoclinic zirconium dioxide nanocrystals and evaluate their performance in removing molybdenum ions from acidic solutions.
Synthesis of ZrO₂ nanocrystals using a thermal decomposition method with a single precursor compound.
Characterization of nanosized ZrO₂ using techniques like XRD, SEM, and TEM.
Testing the sorption capacity for Mo(VI) ions in 3.0 M HNO3 solution using isotherm models.
Kinetic analysis of the sorption process using various models to determine the rate-controlling mechanism.
Pure monoclinic ZrO₂ with an average particle size of 14-28 nm was successfully synthesized.
The maximum sorption capacity for Mo(VI) ions was found to be 66.70 mg/g.
The sorption process is better described by the pseudo-second-order model, indicating chemisorption as the primary mechanism.
The sorption behavior fits the Langmuir and Dubinin–Radushkevich isotherm models, suggesting monolayer adsorption on a uniform surface.

Abstract

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

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